JP2015039645A - Maintenance method for liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a maintenance method for a liquid discharge head which prevents occurrence of clogging in a nozzle opening and can maintain good discharge in discharging of functional ink which is reactive with moisture in the atmosphere.SOLUTION: A maintenance method for a liquid discharge head, which coats a substrate with functional ink having reactivity with water by discharging the ink from a discharge port by ink jetting, includes: a capping process of capping a discharge surface with a cap member which forms a sealed space with a discharge surface of the liquid discharge head; a gas purge process of purging an inside of the cap member with atmosphere gas with adjusted humidity; and a discharge process of discharging a part of the functional ink in the discharge port of the liquid discharge head in a capped state. The gas purge process is carried out before the discharge process.

Description

  The present invention relates to a maintenance method for a liquid discharge head used for manufacturing a thin film such as an electromechanical conversion film.

2. Description of the Related Art An ink jet recording apparatus used as an image forming apparatus such as a printer, a facsimile machine, and a copying apparatus includes a liquid ejection head (hereinafter also referred to as “ink jet head”) that ejects liquid droplets (ink droplets) onto an object to be coated.
The liquid ejection head includes a nozzle that ejects ink droplets, a pressure chamber (also referred to as an ink flow path, a pressure liquid chamber, a pressure chamber, a discharge chamber, and a liquid chamber) that communicates with the nozzle, and a pressure chamber. Energy generated by the energy generation means, comprising: an electromechanical conversion element such as a piezoelectric element that pressurizes the ink, or an electrothermal conversion element such as a heater; a diaphragm that forms a wall surface of the ink flow path; and an energy generation means. As a result, an ink droplet is ejected from a nozzle by pressurizing ink in a pressurizing chamber.

  If the droplet discharge head is left in the air during standby of the ink jet recording apparatus or the like, the ink solvent evaporates over time, so that the ink dries and the ink viscosity near the nozzle holes increases and the ink is discharged. It may become difficult to be discharged. A method for preventing the occurrence of such a discharge failure has been proposed (see, for example, Patent Documents 1 to 3).

  Patent Document 1 discloses an ink jet recording apparatus having a capping unit that seals a nozzle surface of an ink jet recording head, receives a negative pressure from a negative pressure generating unit, and sucks and discharges ink from the nozzle. And in patent document 1, in order to prevent the ink containing a water | moisture content from drying, the liquid holding means to hold | maintain the ink sucked and discharged from the nozzle or the ink ejected idle before capping is applied and sealed. It is disclosed that the inside of a space is kept at high humidity with moisture.

  On the other hand, in Patent Document 2, even when the nozzle opening of the droplet discharge head is still sealed by the capping device, clogging of the nozzle opening and the like is enabled by allowing the moisturizing liquid to be supplied into the sealing portion. A processing method for a droplet discharge device that can prevent the above is disclosed.

  Japanese Patent Application Laid-Open No. 2003-259825 discloses a liquid droplet ejection head maintenance method including a capping step in which a cap is brought into contact with a nozzle surface of a liquid ejection head to form a sealed space, and a moisturizing liquid supply step for supplying a moisturizing liquid to the sealed space. Thus, it is disclosed that the functional liquid is prevented from drying. Patent Document 3 discloses that the moisturizing liquid is supplied a plurality of times and the moisturizing liquid accumulated in the sealed space is discharged.

  By the way, in the sol-gel method known as one of methods for producing ceramics or the like, a method of applying a precursor solution by an ink jet method has been proposed. For example, a technique is known in which a functional ink (for example, PZT precursor) is dropped onto a thin electromechanical conversion film constituting an electromechanical conversion element of an inkjet head by an inkjet method to form a predetermined pattern ( For example, see Patent Document 4).

  In Patent Document 4, an electromechanical conversion film is formed on a first electrode formed on a substrate by an ink jet method, and a second electrode is formed on the electromechanical conversion film. A sol-gel method is used in the forming process, and a technique for applying the precursor liquid by inkjet is disclosed.

A functional ink such as a precursor sol-gel ink used in the sol-gel method may react with moisture in the atmosphere to cause a hydrolysis / polycondensation reaction and stick to the nozzle opening.
That is, the precursor liquid filled in the liquid discharge head of the thin film manufacturing apparatus adheres not only to the volatilization of the solvent at the nozzle opening but also to the reaction with water in the atmosphere during the rest or standby of the apparatus, and clogs the nozzle. Therefore, there is a problem that it is difficult to obtain the effect of preventing the occurrence of defective discharge only by preventing drying from the nozzle openings by the methods described in Patent Documents 1 to 3 and the like.

  In a liquid discharge head that discharges a functional ink such as a sol-gel precursor liquid (PZT precursor) by an inkjet method, the occurrence of clogging due to ink sticking at the nozzle opening of the liquid discharge head is prevented, and good discharge is maintained. There is a need for technology that can

  In view of the above problems, the present invention provides a liquid ejection head maintenance method capable of preventing clogging at the nozzle opening and maintaining good ejection in ejecting functional ink that easily reacts with moisture in the atmosphere. The purpose is to provide.

  In order to solve the above-mentioned problems, a maintenance method for a liquid discharge head according to the present invention is a maintenance method for a liquid discharge head in which functional ink having reactivity with water is discharged from a nozzle by an inkjet method and applied onto a substrate. A capping step of capping the ejection surface with a cap member that forms a sealed space with the ejection surface of the liquid ejection head; and a gas purging step for filling the cap member with an atmospheric gas with adjusted humidity. A liquid discharge head that discharges functional ink in the vicinity of the nozzles of the liquid discharge head in a state where the gas purge process is performed before the idle discharge process. is there.

  According to the present invention, it is possible to provide a liquid ejection head maintenance method capable of preventing clogging at a nozzle opening and maintaining good ejection in ejecting functional ink that easily reacts with moisture in the atmosphere. Can do.

It is a schematic diagram which shows an example of the maintenance method of the liquid discharge head of this embodiment. 5 is a flowchart illustrating an example of a maintenance method for a liquid discharge head according to the present embodiment. It is a schematic diagram which shows the other example of the maintenance method of the liquid discharge head of this embodiment. It is a schematic diagram which shows an example of the maintenance means of the liquid discharge head of this embodiment. It is a flowchart which shows an example of the synthesis | combining method of functional ink (precursor liquid). It is explanatory drawing which shows an example of the formation method of an electromechanical conversion element. It is a perspective view which shows an example of a thin film manufacturing apparatus. It is explanatory drawing which shows the other example of the formation method of an electromechanical conversion element.

  A maintenance method for a liquid ejection head according to the present invention is a maintenance method for a liquid ejection head in which a functional ink having reactivity with water is ejected from a nozzle by an inkjet method and applied onto a substrate. A capping step of capping the ejection surface with a cap member that forms a sealed space therebetween, a gas purging step for filling the cap member with an atmospheric gas whose humidity is adjusted, and a nozzle of the liquid ejection head in the capped state An empty discharge step of discharging a nearby functional ink, and the gas purge step is performed before the empty discharge step.

  Hereinafter, a maintenance method for a liquid discharge head according to the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

FIG. 1 is a schematic diagram illustrating an example of a maintenance method for a liquid discharge head.
FIG. 1A schematically shows a capping process. In the capping process, the cap member 60 is pressed against the nozzle surface 208a on which the nozzles (not shown) of the liquid discharge head 208 are formed to form a sealed space. It is formed. A seal member 61 is provided between the cap member 60 and the nozzle surface 208a, and adhesion between the cap member 60 and the nozzle surface 208a is improved.
FIG. 1B schematically shows a gas purge process, in which an atmosphere gas supply means 70 and an atmosphere gas supply pipe 71 are illustrated as purge means. In the gas purge step, the valve 1 (reference numeral 81) is opened, and low-humidity atmospheric gas is supplied from the connected atmospheric gas supply means 70 through the atmospheric gas supply pipe 71 connected to the inside of the cap member 60. At the same time, by opening the valve 2 (reference numeral 82), excess atmospheric gas is discharged through the exhaust pipe 80 so that the inside of the cap member 60 does not become positive pressure. The arrow in FIG. 1 (B) schematically shows the direction in which the low-humidity atmospheric gas travels. Then, after sufficiently replacing with the atmospheric gas, the two valves are closed.
FIG. 1C is a diagram schematically showing the idle ejection process. In the idle ejection process, the liquid inside the liquid ejection head is ejected as droplets 83 toward the cap member 60 (empty ejection), and the nozzle is refreshed. To do. Thereafter, the liquid ejection device enters a standby state schematically represented in FIG.

  FIG. 2A shows a process flow of an example of the maintenance method of the liquid discharge head. FIG. 2A shows an example in which the capping step (S101), the gas purge step (S102), the idle discharge step (S103), and the standby state (S103) are in this order.

  Details of the functional ink will be described later, but the functional ink having reactivity with water reacts with moisture in the atmosphere to cause hydrolysis and polycondensation reaction to gel, and is fixed at the nozzle opening of the liquid discharge head 208. This will cause clogging of the nozzle. Therefore, by adopting the configuration shown in FIGS. 1A and 1B, the humidity of the atmosphere in the sealed space inside the sealed cap member can be reduced, and nozzle clogging can be prevented. it can.

  However, before performing the capping process, the precursor liquid near the nozzle opening has already reacted with moisture in the air, and the hydrolysis / polycondensation reaction has started, so the functional ink has gelled and clogged the nozzle. It becomes a cause. By performing the capping step, the humidity of the atmosphere inside the cap member 60 is lowered, and the reaction between the precursor liquid and new moisture in the air can be suppressed. However, hydrolysis / polycondensation reaction with water already taken into the precursor liquid Can not be stopped.

Therefore, as shown in FIG. 1C, the precursor liquid containing water in the vicinity of the nozzle opening is removed from the nozzle by empty discharge into the sealed space inside the cap member 60 maintained in a low humidity atmosphere. Thus, the effect of preventing nozzle clogging can be enhanced.
In addition, since the sealed space is formed, the droplets adhering to the vicinity of the nozzle opening and the solvent volatilized from the droplets discharged into the cap member 60 by the idle discharge remain in the sealed space and the vapor pressure of the solvent remains. Increased gradually. As a result, drying of the solvent from the nozzle opening is suppressed, and nozzle clogging can be more reliably prevented.
Accordingly, the liquid discharge head can be kept on standby in a state where only the precursor whose reaction with moisture is suppressed remains in the liquid discharge head, and nozzle clogging can be more reliably prevented.

  Note that it is considered that the reaction between the precursor liquid and water can be prevented if the entire coating apparatus is in a low humidity atmosphere. However, it is known that the film quality such as the ferroelectric characteristics of the thin film formed by the applied precursor liquid is greatly influenced by the humidity at the time of application (for example, Non-Patent Document 1: T. Schneller, R. Waser, J. Sol-Gel Sci. Technol., 42, 337 (2007).). For this reason, it is preferable that the humidity of the atmosphere at the time of application and the humidity of the atmosphere inside the cap member 60 can be controlled independently, and the method according to the present invention is effective.

In the present invention, the low-humidity atmospheric gas is not particularly limited, and examples thereof include dry nitrogen. The low humidity atmospheric gas may be any gas that suppresses moisture and can prevent the functional ink from reacting with moisture in the atmosphere to cause hydrolysis and polycondensation reaction.
The humidity of the atmosphere inside the cap member 60 during the rest or standby of the apparatus is preferably 10 g / kg (DA: abbreviation of dry air) or less in terms of absolute humidity, and is 5 g / kg (DA) or less. Is more preferable.
For example, when the precursor liquid described later as functional ink is filled in the liquid discharge head 208 and left in an atmosphere with a humidity of 10 g / kg (DA), the time until nozzle clogging occurs is about 1 minute. . On the other hand, when left in an atmosphere with a humidity of 5 g / kg (DA), the nozzles were not clogged even after 10 minutes.

  In the present invention, the process flow shown in FIG. 2A is an example, and the order of the processes can be changed as necessary. For example, when the low humidity inside the cap member 60 cannot be maintained for a long time due to the airtightness, the gas purge step (S102) may be performed from the standby state (S104) as necessary. Further, in order to prevent clogging of the nozzle due to the influence of the solvent, the idle discharge step (S103) may be performed as necessary from the standby state (S104). The discharge of the precursor liquid from the nozzle in the idle discharge step (S103) is not limited to a specific means, and for example, the inside of the capping member 60 may be sucked and discharged by making a negative pressure.

However, the gas purge process (S102) needs to be performed at least once before the idle discharge process (S103). As described above, by reducing the humidity inside the cap member 60 and performing the empty ejection step (S103), the vapor pressure of the solvent is increased by the solvent volatilized from the ejected droplets, and the nozzle is more clogged. This is because it can be surely prevented.
On the other hand, when the idle discharge step (S103) is performed before the gas purge step (S102), the precursor liquid reacts with moisture in the atmosphere by the subsequent capping step (S101) and the gas purge step (S102). However, since the precursor in the vicinity of the nozzle opening that has already reacted with moisture remains in the liquid discharge head, clogging of the nozzle cannot be prevented more reliably.

  FIG. 3 is a schematic diagram illustrating another example of a maintenance method for the liquid discharge head. FIG. 3 shows an example in which a gas purge process is performed prior to the capping process. The process flow corresponding to FIG. 3 is shown in FIG.

  FIG. 3A shows a schematic diagram when the gas purge step (S201) is performed prior to the capping step, and is close to the extent that the cap member 60 does not contact the nozzle surface 208a of the liquid discharge head in advance. It has been. Then, the valve 1 (reference numeral 81) is opened, and low-humidity atmospheric gas is supplied from the connected atmospheric gas supply means 70 via the atmospheric gas supply pipe 71 connected to the inside of the cap member 60. At this time, the atmosphere inside the cap member 60 is pushed out by the supplied low-humidity atmospheric gas and discharged through the gap between the cap member 60 and the nozzle surface 208a. The arrows in FIG. 3A schematically show the direction in which the low-humidity atmospheric gas travels. Note that when supplying low-humidity atmospheric gas, it is necessary to suppress the supply of low-humidity atmospheric gas to such an extent that the nozzle is not affected.

  FIG. 3B is a diagram schematically showing the capping step (S202). After the inside of the cap member 60 is replaced with a sufficiently low atmospheric gas, the valve 1 (reference numeral 81) is closed and immediately thereafter. The nozzle surface 208 a of the liquid discharge head is pressed against the cap member 60.

FIG. 3C is a diagram schematically showing the idle ejection step (S203), which is the same as the idle ejection step (S103). FIG. 3D schematically shows the standby state (S204), which is the same as the standby state (S104).
As shown in FIG. 3, unlike the case of FIG. 1, in this embodiment, it is not necessary to prepare the valve 2 and the exhaust pipe, so that the configuration becomes easy.

Next, another aspect of the maintenance method of the liquid discharge head is shown in FIG.
FIG. 4 shows a configuration including a liquid holding unit 62 that can hold a liquid inside the cap member 60 and a liquid level sensor 63.
The liquid held in the liquid holding unit 62 is a liquid composed of at least one component constituting the solvent of the functional ink. Although the solvent of the functional ink will be described later, in this embodiment, for example, 2-methoxyethanol which is a component constituting the solvent in the PZT precursor liquid can be selected.

  In the embodiment shown in FIG. 4, the atmosphere gas / liquid supply pipe 65 and the atmosphere gas / liquid supply means 64 are connected to the inside of the cap member 60, and means for supplying low-humidity atmosphere gas and means for supplying liquid Can switch the supply of the atmospheric gas and the liquid by switching a switching valve (not shown).

  In the present embodiment, first, the liquid level sensor 63 detects the liquid level of the liquid holding unit 62 before capping, and when the liquid level is low, the liquid is supplied from the atmospheric gas / liquid supply means 64 to the liquid holding unit 62. . Next, low-humidity atmospheric gas is supplied from the atmospheric gas / liquid supply means 64, and the atmosphere inside the cap member 60 is replaced with low-humidity atmospheric gas. Thereafter, the cap member 60 is pressed against the nozzle surface 208a of the liquid discharge head 208 to perform capping.

  According to the configuration of FIG. 4, since the solvent is volatilized not only from the precursor liquid at the nozzle opening but also from the liquid in the liquid holding unit 62, the vapor pressure of the solvent quickly increases, as shown in FIGS. 1 and 3. Drying of the solvent is suppressed rather than the configuration, and clogging of the nozzle can be prevented.

  In the present embodiment, by further discharging (empty discharge) the ink in the liquid discharge head, the precursor liquid in the vicinity of the nozzle opening that has already reacted with moisture is discharged, and nozzle clogging can be more reliably prevented. it can.

[Functional ink]
A functional ink that is used in a liquid discharge head that is an object of the maintenance method of the liquid discharge head of the present invention and has reactivity with water will be described. The functional ink ejected from the nozzle of the liquid ejection head and applied onto the substrate can be appropriately selected according to the type of thin film to be produced. For example, the metal in the case of producing an electromechanical conversion film Examples include functional inks containing alkoxide, and examples of the metal alkoxide include those containing at least one of Pb, Zr and Ti.

Hereinafter, an example using a precursor liquid used when forming a film of PZT (lead zirconate titanate) as a functional ink by a sol-gel method will be described. The synthesis of the precursor liquid is performed according to a method described in literature (for example, Non-Patent Document 2: T. Iijima, et al., Int. J. Appl. Ceram. Technol., 3, 442 (2006)). Can be performed.
An example of the flow of a method for synthesizing functional ink is shown in FIG.

As starting materials for the PZT precursor liquid, lead acetate trihydrate Pb (CH ₃ COO) ₂ .3H ₂ O, zirconium tetranormal propoxide Zr (OCH ₂ CH ₂ CH ₃ ) ₄ , titanium tetraisopropoxide Ti [ OCH (CH ₃ ) ₂ ] ₄ can be used.
These starting materials are composed of Pb (Zr _0.53 , Ti _0.47 ) O ₃ , generally lead zirconate titanate, generally indicated as PZT (53/47), with a lead content of 20 mol. It is weighed so that the composition becomes% excess, that is, Pb _1.20 (Zr _0.53 , Ti _0.47 ) O ₃ . This is to prevent the deterioration of crystallinity caused by so-called “lead loss” that occurs during the heat treatment of the applied sol-gel liquid film.

After weighing, first, lead acetate trihydrate is dissolved in ₂ -methoxyethanol CH ₃ OCH ₂ CH ₂ OH as a main solvent (S301). Next, heating and refluxing are performed at the boiling point of the solvent (S302), and hydrate dehydration and alcohol exchange treatment of lead acetate are performed (S303).

  Subsequently, zirconium tetranormal propoxide and titanium tetraisopropoxide are added to the 2-methoxyethanol solution of lead acetate subjected to dehydration and alcohol exchange treatment (S304), heated and refluxed (S305), and alcohol exchange is performed. The reaction and polycondensation reaction are allowed to proceed (S306).

An alkoxide compound is dissolved in a 2-methoxyethanol solution, a small amount of acetic acid CH ₃ COOH is added as a stabilizer to prevent hydrolysis of the metal alkoxide (S307), the solid content concentration is adjusted (S308), and the PZT precursor A body sol-gel solution is obtained (S309). In step S308, the solid content concentration can be, for example, 0.5 mol / L, but is not limited thereto.

Next, an ink forming step for applying the obtained precursor sol-gel solution as a functional ink by a thin film manufacturing apparatus by an inkjet method is performed (S310).
In the preparation of the functional ink in the ink forming process in step S310, in order to adjust the drying speed of the ink, the solvent component (main solvent) that is compatible with the prepared precursor liquid and is used in the precursor liquid before preparation is used. The solvent having a boiling point higher than that of the above (hereinafter referred to as “sub-solvent”) is added and stirred. Any one or more of alcohols, glycols, and ethers can be used as a subsolvent. By adding such a subsolvent, it can be stably applied by an ink jet method. An inking precursor liquid is obtained.

In the present embodiment, 2-methoxyethanol is used as the main solvent, and 1-nonanol (CH ₃ (CH ₂ ) ₈ OH) having a higher boiling point than the main solvent and good compatibility with the sol-gel solution is used as the auxiliary solvent. Can do. A functional ink is obtained by setting the volume ratio of the main solvent and the sub-solvent to 1: 1 and diluting the solid content concentration of the precursor liquid. As solid content concentration, although it can be set as 0.3 mol / L, for example, it is not limited to this.

[Electromechanical conversion film, electromechanical conversion element]
The liquid discharge head targeted by the maintenance method of the liquid discharge head in the present embodiment applies functional ink on a substrate to manufacture an electromechanical conversion film, an electromechanical conversion element, and the like. The electromechanical conversion film and the electromechanical conversion element to be manufactured are not particularly limited. For example, the first electrode which is a substrate, the second electrode facing the first electrode, and the first electrode And an electromechanical conversion element including an electromechanical conversion film sandwiched between the second electrode and the second electrode. An example will be described below.

6 and 8 are cross-sectional views showing the manufacturing process of the electromechanical conversion film and the electromechanical conversion element.
The manufacturing process of the present embodiment shown in FIGS. 6 and 8 relates to a method of directly patterning by applying the functional ink to a desired region on the substrate by an inkjet method using the thin film manufacturing apparatus. .

In the step shown in FIG. 6A, a TiO ₂ film having a thickness of 50 nm is formed on the upper surface of the substrate 51 as an underlayer 52, and platinum (Pt) and strontium ruthenium oxide (SRO) are formed as first electrodes 53 and 54. Are sequentially stacked. In the present embodiment, the Pt film thickness of the first electrode 53 is 250 mm and the SRO film thickness of the first electrode 54 is 60 nm, but the film thickness is not limited to this.

  In the step shown in FIG. 6B, the photoresist 55 is patterned by photolithography so that the first electrode 54 matches the pattern formed as an electromechanical conversion film by an inkjet method, and electromechanical conversion is performed by dry etching. The SRO layer existing on the surface outside the element pattern region is etched. Subsequently, in the step shown in FIG. 6C, the photoresist 55 remaining on the electromechanical conversion element pattern is peeled off.

The electromechanical conversion film pattern of the present embodiment is a long pattern having a width of 45 μm and a length of 1000 μm, and is arranged at a 1: 1 pitch (pattern width = space width = 45 μm) in the width direction. it can.
The surface outside the electromechanical conversion element pattern region after the patterning step in FIG. 6B is in a state where Pt under the first electrode 53 exists.

In the step shown in FIG. 6D, a surface treatment is performed on the entire surface of the substrate 51 to form a SAM film (Self Assembled Mono-Layer) 56 outside the electromechanical conversion element pattern region. The SAM film 56 is obtained by immersing the substrate in an alkanethiol dilution and allowing the thiol groups to self-align. Here, as the alkanethiol, dodecanethiol CH ₃ (CH ₂ ) ₁₁ —SH is used, and an ethanol dilution solution having a molar concentration of 0.1 mmol / L is used. The immersion time of the substrate 51 in the alkanethiol solution is 10 seconds, and after the immersion, ultrasonic cleaning is performed in an ethanol bath for 5 minutes.

  As a result, the contact angle with respect to pure water inside / outside the electromechanical conversion element pattern area of the substrate is 100 degrees or more outside the pattern area, and sufficient hydrophobicity is obtained, and it becomes 40 degrees or less within the pattern area and becomes hydrophilic. . A large contact angle contrast inside / outside the pattern area can be secured by the above-described steps.

Subsequently, in the step shown in FIG. 6E, the functional region (precursor liquid) 207 is formed into a hydrophilic region 59 on the substrate, that is, a desired electromechanical conversion film pattern by a thin film manufacturing apparatus equipped with a liquid discharge head 208. Apply to area.
In addition, the thin film manufacturing apparatus used for coating includes a maintenance unit 209 as shown in FIG. 7, and the maintenance unit 209 can carry out each process shown in FIG. 1 and FIG.
Since the functional ink (precursor liquid) 207 has a contact angle contrast inside / outside the electromechanical conversion film pattern forming region as described above, the sol-gel liquid 57a spreads only to the hydrophilic portion, as shown in FIG. Thus, a pattern is formed.

  In the first heating step, that is, the step of drying the solvent, the substrate bottom surface is heated by a hot plate, and the temperature is raised from room temperature to 120 ° C. at a rate of temperature rise of 30 ° C./min. Heat treatment is performed until 57a is dried.

  After the sol film is dried in this step, the second heating step, that is, the thermal decomposition treatment of the organic substance is performed at a temperature of 500 ° C., and the PZT film 57b having the electromechanical conversion film pattern as shown in FIG. Form. The film thickness of the formed electromechanical conversion film is 80 nm at the center of the pattern.

Subsequently, in the step shown in FIG. 8 (H), after performing isopropyl alcohol cleaning as a repetitive treatment, surface treatment of the substrate is performed by dipping in a thiol diluent as in the step of FIG. 6 (D). 56 is formed.
Since the SAM film 56 is not formed on the oxide film, that is, the PZT film 57b after the second time, the pattern of the SAM film 56 as shown in FIG.
The contact angle with respect to pure water at this time is 100 degrees or more outside the electromechanical conversion film pattern region (on the SAM film 56) and 25 degrees or less on the PZT film 57b.

Next, as shown in FIG. 8 (I), FIG. 8 (J), and FIG. 8 (K), alignment is performed on the electromechanical conversion film pattern formed for the first time, and the liquid ejection head is used again using the thin film manufacturing apparatus. The functional ink 207 is applied by 208.
After the coating, as in the first coating, after a drying step by a temperature increase from room temperature to 120 ° C. at a temperature rising rate of 30 ° C./min, an organic matter thermal decomposition treatment step at a temperature of 500 ° C., and then a crystallization treatment (Temperature 750 ° C.) is performed by RTA (rapid heat treatment), and the overcoated PZT film 57b is obtained. According to such a process, defects such as cracks do not occur in the film.

  Subsequently, a series of steps from formation of the SAM film 56 by surface treatment, application of the functional ink 207, drying, thermal decomposition, formation of the SAM film 56, application of the functional ink 207, drying, thermal decomposition, and crystallization treatment. Can be produced by performing 3 to 30 cycles under the same conditions as described above. As the number of cycles, for example, 21 cycles can be used.

An upper electrode (platinum) was formed on the electromechanical conversion pattern film obtained by the above method, and the electrical characteristics and electromechanical conversion ability (piezoelectric constant) were evaluated.
As a result, the relative permittivity of the electromechanical conversion film was 1400, the dielectric loss was 0.05, and the withstand voltage was 50 V, indicating that it has excellent electrical characteristics.
Further, the remanent polarization was 12.2 μC / cm ² , the coercive electric field was 28.1 kV / cm, and the characteristics were equivalent to those of a normal ceramic sintered body.
Furthermore, the electromechanical conversion capacity was calculated by measuring the amount of deformation by applying an electric field with a laser Doppler vibrometer and fitting it by simulation. As a result, the piezoelectric constant d31 was 142 pm / V, which was the same value as the ceramic sintered body. From the above results, the electromechanical conversion film of this embodiment has characteristics that can be sufficiently designed as an electromechanical conversion element constituting the liquid ejection head.

[Thin film manufacturing equipment]
Next, an example of a thin film manufacturing apparatus provided with maintenance means capable of performing the maintenance method of the liquid discharge head according to the present embodiment will be described.
The thin film manufacturing apparatus according to this embodiment is, for example, a stage that holds a substrate and a functional ink that is disposed opposite to the stage and has reactivity with water is ejected from a nozzle by an inkjet method onto the substrate. The liquid discharge head etc. which apply | coat and the thing provided with the maintenance means are mentioned.

The stage and / or the liquid discharge head is relatively moved to discharge the functional ink onto the substrate and apply in an arbitrary pattern, and the functional ink on the substrate is heated and crystallized. And a heating mechanism unit that is a functional thin film.
In addition, as a means for heating the functional ink in the heating mechanism section, a heating means such as a hot plate, an oven, a halogen lamp, a xenon lamp, an infrared lamp, or a laser irradiation means such as a YAG laser, a CO ₂ laser, an Ar laser, etc. Is used.

Hereinafter, the liquid discharge application mechanism unit of the thin film manufacturing apparatus will be described.
FIG. 7 is a perspective view showing a configuration example of a liquid discharge coating mechanism used in the thin film manufacturing apparatus.
As shown in FIG. 7, the liquid discharge application mechanism is a so-called inkjet coating apparatus, which is a base 200 serving as a base of the apparatus, and a Y-axis drive that is installed on the base 200 and moves the stage 203 in the Y-axis direction. Means 201, a stage 203 which is installed on the Y-axis driving means 201 and holds the substrate 202 thereon, and is disposed opposite to the stage 203 and ejects functional ink (inkjet head). ) 208, a Z-axis drive unit 211 that supports the liquid discharge head 208 via the head base 206 and moves it in the Z-axis direction, and supports the liquid discharge head 208, the head base 206, and the Z-axis drive unit 211 to support X. An X-axis drive unit 205 that moves in the axial direction, an X-axis support member 204 that supports the X-axis drive unit 205, and head maintenance And a Nsu means 209.

  Here, the liquid discharge head 208 is not particularly limited, but for example, a diaphragm, an electromechanical conversion element that is a piezoelectric element provided on the diaphragm, and a pressure chamber filled with functional ink. (Also referred to as an individual liquid chamber) and a nozzle plate in which nozzles, which are droplet ejection holes for ejecting functional ink, are provided corresponding to the pressure chambers.

In the liquid discharge head 208 configured as described above, an upper portion corresponding to a nozzle to be discharged by the oscillation circuit based on predetermined pattern data from the control unit in a state where the functional ink is filled in each pressure chamber. A pulse voltage is applied to the electrode. By applying this voltage pulse, the electromechanical conversion film is flexed so that the diaphragm becomes convex toward the pressure chamber 21 side by contracting in parallel with the diaphragm due to the piezoelectric effect. become. As a result, the pressure in the pressure chamber rises rapidly, and the functional ink is ejected from the nozzle communicating with the pressure chamber. At this time, several tens to several hundreds of droplets are continuously discharged from the nozzle. Next, after applying the pulse voltage, the contracted electromechanical conversion film returns to its original position, so that the deflected diaphragm returns to its original position, and functional ink is supplied from a common liquid chamber (not shown) to the pressure chamber. .
By repeating the above-described operation control, the liquid ejection head 208 can continuously eject functional ink droplets. It should be noted that functional ink is supplied from an ink tank (not shown) to the liquid discharge head 208 via the ink supply pipe 210.

  The stage 203 has an adsorbing unit that adsorbs and holds the substrate 202 on the main surface of the stage 203 using vacuum, static electricity, or the like.

The head maintenance unit 209 includes a capping unit for capping the ejection surface of the liquid ejection head 208, a purge unit for filling the cap member with a low humidity atmosphere gas, and an empty ejection unit for idly ejecting the liquid of the liquid ejection head.
The liquid discharge head 208 is moved to the head maintenance means 209 side during the rest or standby of the apparatus and is capped by the capping means to protect the discharge surface from drying and reaction with moisture in the air.

51 Substrate 52 Underlayer (TiO ₂ )
53 First electrode (Pt)
54 First electrode (SRO)
55 Photoresist 56 SAM film 57a Sol film 57b PZT film 58 Hydrophobic part 59 Hydrophilic part (SRO)
60 Cap member 61 Inside cap member 62 Liquid holding portion 63 Liquid level sensor 64 Atmospheric gas / liquid supply means 65 Atmospheric gas / liquid supply pipe 70 Atmospheric gas supply means 71 Atmospheric gas supply pipe 80 Exhaust pipe 81 Valve 1
82 Valve 2
83 Droplet 200 Base 201 Y-axis driving means 202 Substrate 203 Stage 204 X-axis indicating member 205 X-axis driving means 206 Head base 207 Functional ink 208 Liquid discharge head 208a Nozzle surface 209 Head maintenance means 210 Ink supply pipe 211 Z-axis Driving means

JP 2001-71514 A Japanese Patent No. 4352915 JP 2010-194514 A JP 2011-9726 A

T. Schneller, R. Waser, J. Sol-Gel Sci. Technol., 42, 337 (2007). T. Iijima, et al., Int. J. Appl. Ceram. Technol., 3, 442 (2006).

Claims (5)

In a maintenance method of a liquid discharge head in which functional ink having reactivity with water is discharged from a nozzle by an inkjet method and applied onto a substrate,
A capping step of capping the ejection surface with a cap member that forms a sealed space with the ejection surface of the liquid ejection head;
A gas purging step for filling the cap member with an atmospheric gas whose humidity is adjusted;
An empty discharge step of discharging functional ink in the vicinity of the nozzle of the liquid discharge head in the capped state,
A maintenance method for a liquid discharge head, wherein the gas purge step is performed before the idle discharge step.   The maintenance method for a liquid discharge head according to claim 1, wherein the functional ink contains a metal alkoxide.   The method for maintaining a liquid discharge head according to claim 2, wherein the metal alkoxide contains at least one selected from Pb, Zr, and Ti.   The method for maintaining a liquid discharge head according to any one of claims 1 to 3, wherein the humidity of the atmosphere inside the cap member is 10 g / kg (DA) or less when the apparatus is at rest or on standby. A liquid holding part capable of holding a liquid inside the cap member;
5. The maintenance of the liquid discharge head according to claim 1, wherein the liquid held in the liquid holding part is a liquid composed of at least one component constituting a solvent of the functional ink. Method.