JP2011161903A - Nozzle plate, nozzle plate manufacturing method, liquid droplet ejecting head, and liquid droplet ejecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle plate, a liquid droplet ejecting head and a liquid droplet ejecting apparatus having improved durability, and capable of performing high-quality printing over a long period of time, and to provide a nozzle plate manufacturing method of easily manufacturing the nozzle plate. <P>SOLUTION: The nozzle plate 11 includes: a substrate 112 in which a plurality of nozzle holes 111 for ejecting liquid droplets are formed; a liquid repelling film 113 disposed on the upper surface of the substrate 112, and composed of a coupling agent; and first and second base films 114 and 115 disposed between the substrate 112 and the liquid repelling film 113, and composed of a plasma polymerization film. The plasma polymerization film includes: an Si-skeleton including siloxane-bond; and a leaving group made of an organic group bonded to the Si-skeleton, and the plasma polymerization film exhibits adhesion when energy is imparted. The substrate 112 and the liquid repelling film 113 firmly adhere to each other with the adhesion of the plasma polymerization film. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a nozzle plate, a method for manufacturing a nozzle plate, a droplet discharge head, and a droplet discharge device.

As a droplet discharge head for discharging droplets, for example, an ink jet recording head provided in an ink jet printer is known.
An ink jet recording head generally has a nozzle plate, and a plurality of fine ink ejection openings for ejecting ink are formed on the nozzle plate at a small interval.

When ink adheres to the surface of the nozzle plate (the surface on the ink ejection side), the ink ejected thereafter is affected by the surface tension and viscosity of the adhered ink, and the ejection trajectory is bent. As a result, there is a problem that ink cannot be applied to a predetermined position. For this reason, it is necessary to perform a liquid repellent treatment for preventing ink from adhering to the surface of the nozzle plate.
As a method for imparting liquid repellency to such a nozzle plate surface, a method of forming a liquid repellent film on the surface has been proposed.

  For example, Patent Document 1 discloses a method of forming a liquid repellent film on the surface of a substrate by reacting a coupling agent. This method is a method of forming a liquid repellent film by forming a base film such as silicon dioxide on the surface of a substrate and then reacting a coupling agent with the surface of the base film. Patent Document 1 also discloses forming a liquid repellent film on the nozzle plate.

By the way, the ink jet printer has a wiping function that rubs the nozzle plate with a rubber or cloth wiper so that the ink discharge port is not clogged due to the adhering of dust such as paper dust generated from the recording paper or ink. It has been.
However, the liquid repellent film described in Patent Document 1 has a problem that the interface between the base material and the base film and the interface between the base film and the liquid repellent film are peeled off. The peeling at each interface is easily amplified by the ingress of ink and repeated wiping, leading to the loss of the liquid repellent film. As a result, there is a problem that the base material is corroded by ink and the printing quality is deteriorated during long-term use.

JP 2005-281729 A

  An object of the present invention is to provide a nozzle plate, a droplet discharge head and a droplet discharge device that are excellent in durability and capable of performing high-quality printing over a long period of time, and a nozzle plate manufacturing method capable of easily manufacturing the nozzle plate. It is to provide.

The above object is achieved by the present invention described below.
The nozzle plate of the present invention is provided on a substrate on which a plurality of nozzle holes for discharging droplets are formed and a surface of the substrate on the side for discharging droplets so as to surround at least the periphery of the nozzle holes, Having a liquid repellent film composed of a coupling agent,
It is provided between the substrate and the liquid repellent film, and has two or more base films made of a plasma polymerized film.
As a result, a nozzle plate having excellent durability and capable of performing high-quality printing over a long period of time can be obtained.

The nozzle plate of the present invention has a first base film and a second base film positioned on the liquid repellent film side as the base film of the two or more layers,
The first base film preferably has an average thickness larger than that of the second base film.
As a result, the first base film is firmly adhered to the substrate, and irregularities on the surface of the substrate are absorbed by the first base film, and the surface of the first base film is a highly smooth surface. It becomes. As a result, the substrate and the first base film, and the first base film and the second base film are firmly adhered to each other, and as a result, the liquid repellent film is reliably prevented from being peeled off. can do.
In the nozzle plate of the present invention, it is preferable that the first base film has a crystallinity higher than that of the second base film.
Thereby, the nozzle plate which can relieve | moderate a residual stress and can prevent peeling of a liquid repellent film reliably is obtained.

In the nozzle plate of the present invention, it is preferable that the plasma polymerized film includes a Si skeleton including a siloxane bond and a leaving group bonded to the Si skeleton and including an organic group.
As a result, the base film becomes a strong film that is difficult to deform due to the influence of the Si skeleton including a siloxane bond and having a random atomic structure. Also, the elimination of the leaving group causes the base film to exhibit adhesiveness, thereby contributing to prevention of peeling of the liquid repellent film.
In the nozzle plate of the present invention, it is preferable that the plasma polymerized film is mainly composed of polyorganosiloxane.
Thereby, a base film excellent in adhesion to the liquid repellent film can be obtained.

In the method of manufacturing a nozzle plate according to the present invention, a substrate on which a plurality of nozzle holes for discharging droplets are formed and a surface of the substrate on the side for discharging droplets surround at least the periphery of the nozzle holes. A method of manufacturing a nozzle plate having a liquid repellent film provided,
A first step of forming a base film of two or more layers by a plasma polymerization method on the surface of the substrate on which the droplets are to be discharged;
A second step of applying energy to the surface of the base film;
A third step of supplying a coupling agent to the surface of the base film to form the liquid repellent film.
Thereby, it is possible to easily manufacture a nozzle plate that has excellent durability and can perform high-quality printing over a long period of time.

In the method for manufacturing a nozzle plate of the present invention, it is preferable that the film formation conditions by the plasma polymerization method are different for each layer when forming the base film of two or more layers in the first step.
Thereby, the crystallinity of each layer of the base film can be made different, and the residual stress relaxation function between the layers of the base film can be further enhanced.
The nozzle plate manufacturing method of the present invention preferably further includes a fourth step of heating the base film and the liquid repellent film.
Thereby, hydrolysis is promoted between the base film and the liquid repellent film, and the liquid repellent film is more firmly fixed.

A droplet discharge head according to the present invention includes the nozzle plate according to the present invention.
As a result, a droplet discharge head that is excellent in durability and can perform high-quality printing over a long period of time can be obtained.
The liquid droplet ejection apparatus of the present invention includes the liquid droplet ejection head of the present invention.
Thereby, it is possible to obtain a droplet discharge device that has excellent durability and can perform high-quality printing over a long period of time.

It is the schematic which shows embodiment of an inkjet printer. It is an exploded perspective view showing an embodiment of an ink jet recording head. It is the sectional view on the AA line of the nozzle plate shown in FIG.

Hereinafter, a nozzle plate, a manufacturing method of a nozzle plate, a droplet discharge head, and a droplet discharge device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings. Hereinafter, an ink jet printer will be described as an example of the droplet discharge device.
(inkjet printer)
FIG. 1 is a schematic diagram illustrating an embodiment of an inkjet printer.
The ink jet printer 9 shown in FIG. 1 includes an apparatus main body 92, a tray 921 for installing the recording paper P in the upper rear, a paper discharge port 922 for discharging the recording paper P in the lower front, and an operation panel on the upper surface. 97.

The operation panel 97 includes, for example, a liquid crystal display, an organic EL display, an LED lamp, and the like, and a display unit (not shown) for displaying an error message and the like, and an operation unit (not shown) configured with various switches and the like. And.
Further, inside the apparatus main body 92, mainly a printing apparatus (printing means) 94 provided with a reciprocating head unit 93 and a paper feeding apparatus (paper feeding means) for feeding recording paper P to the printing apparatus 94 one by one. 95 and a control unit (control means) 96 for controlling the printing device 94 and the paper feeding device 95.

  Under the control of the control unit 96, the paper feeding device 95 intermittently feeds the recording paper P one by one. The recording paper P passes near the lower part of the head unit 93. At this time, the head unit 93 reciprocates in a direction substantially orthogonal to the feeding direction of the recording paper P, and printing on the recording paper P is performed. That is, the reciprocating motion of the head unit 93 and the intermittent feeding of the recording paper P are the main scanning and sub-scanning in printing, and ink jet printing is performed.

The printing apparatus 94 includes a head unit 93, a carriage motor 941 that is a drive source of the head unit 93, and a reciprocating mechanism 942 that reciprocates the head unit 93 in response to the rotation of the carriage motor 941.
The head unit 93 has an ink jet recording head 1 (a liquid droplet ejection head of the present invention) having a large number of nozzle holes 111 at a lower portion thereof, an ink cartridge 931 that supplies ink to the ink jet recording head 1, and an ink jet recording. And a carriage 932 on which the head 1 and the ink cartridge 931 are mounted.

Ink cartridge 931 is filled with four color inks of yellow, cyan, magenta, and black (black), thereby enabling full color printing.
The reciprocating mechanism 942 includes a carriage guide shaft 943 whose both ends are supported by a frame (not shown), and a timing belt 944 extending in parallel with the carriage guide shaft 943.

The carriage 932 is supported by the carriage guide shaft 943 so as to be able to reciprocate and is fixed to a part of the timing belt 944.
When the timing belt 944 travels forward and backward through the pulley by the operation of the carriage motor 941, the head unit 93 reciprocates as guided by the carriage guide shaft 943. During this reciprocation, ink is appropriately ejected from the ink jet recording head 1 and printing on the recording paper P is performed.

The sheet feeding device 95 includes a sheet feeding motor 951 serving as a driving source thereof, and a sheet feeding roller 952 that is rotated by the operation of the sheet feeding motor 951.
The paper feed roller 952 includes a driven roller 952 a and a drive roller 952 b that are opposed to each other with a feeding path (recording paper P) of the recording paper P interposed therebetween. The drive roller 952 b is connected to the paper feed motor 951. As a result, the paper feed roller 952 can feed a large number of recording sheets P set on the tray 921 one by one toward the printing apparatus 94. Instead of the tray 921, a configuration in which a paper feed cassette that stores the recording paper P can be detachably mounted may be employed.

The control unit 96 performs printing by controlling the printing device 94, the paper feeding device 95, and the like based on print data input from a host computer such as a personal computer or a digital camera.
Although not shown, the control unit 96 mainly includes a memory that stores a control program for controlling each unit, a piezoelectric element drive circuit that drives the piezoelectric element (vibration source) 14 and controls the ink ejection timing, A driving circuit for driving the printing device 94 (carriage motor 941), a driving circuit for driving the paper feeding device 95 (paper feeding motor 951), a communication circuit for obtaining print data from the host computer, and these electrically And a CPU that is connected and performs various controls in each unit.
In addition, for example, various sensors that can detect the remaining amount of ink in the ink cartridge 931, the position of the head unit 93, and the like are electrically connected to the CPU.

  The control unit 96 obtains the print data via the communication circuit and stores it in the memory. The CPU processes the print data and outputs a drive signal to each drive circuit based on the process data and input data from various sensors. The piezoelectric element 14, the printing device 94, and the paper feeding device 95 are each activated by this drive signal. As a result, printing is performed on the recording paper P.

(Inkjet recording head)
Next, an embodiment of an ink jet recording head to which the droplet discharge head of the present invention is applied will be described.
FIG. 2 is an exploded perspective view showing an embodiment of an ink jet recording head. Note that FIG. 2 is shown upside down from the state of normal use.

Hereinafter, an ink jet recording head (hereinafter simply referred to as “head”) 1 will be described in detail with reference to FIG.
The head 1 shown in FIG. 2 includes a nozzle plate (nozzle plate of the present invention) 11, an ink chamber substrate 12, a vibration plate 13, and a piezoelectric element (vibration source) 14 joined to the vibration plate 13. . The head 1 constitutes an on-demand type piezo jet head.

<Nozzle plate>
The nozzle plate 11 includes a substrate 112 and a liquid repellent film 113 provided on the surface of the substrate 112 on the ink discharge side.
The nozzle plate 11 is formed with a number of nozzle holes 111 for ejecting ink droplets. The pitch between these nozzle holes 111 is appropriately set according to the printing accuracy.

Furthermore, a communication hole 131 is formed at a predetermined position of the nozzle plate 11 so as to penetrate in the thickness direction of the nozzle plate 11. Ink can be supplied from the ink cartridge 931 to the reservoir chamber 123 through the communication hole 131.
Examples of the material constituting the substrate 112 include silicon-based materials such as Si, SiO ₂ , SiN, and quartz glass, Ti, Co, Au, Al, Fe, Ni, Cr, Cu, Sn, Zn, and the like. , Metal materials such as stainless steel (SUS), Sn—Cu—P alloy (phosphor bronze), Cu—Zn alloy, alumina, iron oxide, tin oxide, indium tin oxide (ITO), antimony oxide (ATO), oxide materials such as indium zinc oxide (IZO), polyethylene terephthalate, polyimide, polystyrene, acrylonitrile butadiene styrene copolymer (ABS resin), polyacetal, polycarbonate, plastic materials such as polysulfone, carbon black Like graphite Motokei material, and the like.

FIG. 3 shows a cross-sectional view of the nozzle plate 11 shown in FIG.
As shown in FIG. 3, the nozzle plate 11 includes the substrate 112 and the liquid repellent film 113 described above, and two layers of base films 114 and 115 provided therebetween. In the following description, the upper side of FIG. 3 is referred to as “upper” and the lower side is referred to as “lower”. In FIG. 2, the two underlying layers 114 and 115 are omitted.
Of the two layers of base films 114 and 115, the base film on the substrate 112 side is the first base film 114, and the base film on the liquid repellent film 113 side is the second base film 115. These base films 114 and 115 are each formed of a plasma polymerization film.

Hereinafter, the first base film 114 will be described. Note that the second base film 115 has the same structure as the first base film 114.
The first base film 114 is composed of a plasma polymerization film. Examples of the plasma polymerized film include a silane plasma polymerized film and an alkyl plasma polymerized film. Here, the silane-based plasma polymerized film will be described, but the following matters are the same for other plasma polymerized films.

  The silane-based plasma polymerized film is formed by a plasma polymerization method using a silane-based material described later as a raw material. The structure includes a Si skeleton including a siloxane bond and having a random atomic structure (amorphous structure), and a leaving group composed of an organic group bonded to the Si skeleton. Such a plasma polymerized film is a strong film that is difficult to be deformed due to the influence of the Si skeleton including a siloxane bond and having a random atomic structure. This is presumably because the crystallinity of the Si skeleton becomes low (becomes amorphous), so that defects such as dislocations and misalignments at the crystal grain boundaries hardly occur. For this reason, the first base film 114 formed of a plasma polymerization film has excellent chemical characteristics such as chemical resistance and weather resistance.

In addition, the plasma polymerized film has a property that, when energy is applied, a leaving group bonded to the Si skeleton is eliminated and an active hand is generated. This active hand expresses adhesiveness to other members. Therefore, the first base film 114 formed of a plasma polymerization film has excellent adhesion to the adjacent substrate 112 and the second base film 115.
The bond energy between the leaving group composed of an organic group and the Si skeleton is smaller than the bond energy of the siloxane bond that forms the Si skeleton. For this reason, the plasma polymerized film can selectively break the bond between the leaving group and the Si skeleton by the application of energy without breaking the Si skeleton, thereby detaching the leaving group.

  In the silane-based plasma polymerized film, it is preferable that the total of the Si atom content and the O atom content is about 10 atom% or more and 90 atom% or less among atoms excluding H atoms from all atoms. More preferably, it is about 20 atom% or more and 80 atom% or less. If Si atoms and O atoms are contained in the above-mentioned range, the plasma polymerized film forms a strong network of Si atoms and O atoms, and has better chemical properties.

The abundance ratio of Si atoms to O atoms in the plasma polymerized film is preferably about 3: 7 to 7: 3, more preferably about 4: 6 to 6: 4. By setting the abundance ratio of Si atoms and O atoms to be within the above range, the stability of the plasma polymerized film becomes higher.
Here, the degree of crystallinity of the plasma polymerized film is preferably 45% or less, and more preferably 40% or less. As a result, the plasma polymerized film exhibits more amorphous characteristics.

The crystallinity of the plasma polymerized film can be measured by a general crystallinity measurement method. Specifically, the measurement is based on the intensity of scattered X-rays in the crystal portion (X-ray method). , The method of obtaining from the intensity of the crystallization band of infrared absorption (infrared method), the method of obtaining based on the area under the differential curve of nuclear magnetic resonance absorption (nuclear magnetic resonance absorption method), It can be measured by a chemical method utilizing the difficulty.
Among these, the X-ray method is preferably used from the viewpoint of convenience and the like.

  The plasma polymerized film preferably contains Si—H bonds in its structure. This Si-H bond is generated in the polymer when the silane undergoes a polymerization reaction by the plasma polymerization method. At this time, if the Si-H bond inhibits the regular formation of the siloxane bond, Conceivable. For this reason, the siloxane bond is formed so as to avoid the Si—H bond, and the regularity of the Si skeleton is lowered. Thus, according to the plasma polymerization method, a film with low crystallinity can be obtained.

  On the other hand, the higher the Si-H bond content, the lower the crystallinity, and in the infrared absorption spectrum of the plasma polymerized film, when the intensity of the peak attributed to the siloxane bond is 1, Si The intensity of the peak attributable to the —H bond is preferably about 0.001 or more and 0.2 or less, more preferably about 0.002 or more and 0.05 or less, and 0.005 or more and 0.02 or less. More preferably, it is about. When the ratio of Si—H bonds to siloxane bonds is within the above range, the plasma polymerized film is relatively most random. For this reason, when the peak intensity of the Si—H bond is within the above range with respect to the peak intensity of the siloxane bond, the plasma polymerized film is particularly excellent in chemical characteristics.

As described above, the leaving group behaves so as to generate an active hand by leaving from the Si skeleton. Therefore, the leaving group is relatively easily and uniformly desorbed by being given energy, but is securely bonded to the Si skeleton so as not to be desorbed when no energy is given. There is a need.
In the film formation by the plasma polymerization method, the component of the source gas is polymerized to generate a Si skeleton containing a siloxane bond and a residue bonded thereto. For example, this residue becomes a leaving group. obtain.

Examples of the atomic group (group) that can be a leaving group include alkyl groups such as methyl and ethyl groups, alkenyl groups such as vinyl and allyl groups, aldehyde groups, ketone groups, carboxyl groups, amino groups, and amides. Group, nitro group, halogenated alkyl group, mercapto group, sulfonic acid group, cyano group, isocyanate group and the like.
Among these groups, the leaving group is particularly preferably an organic group, and more preferably an alkyl group. Since the organic group and the alkyl group have high chemical stability, the plasma polymerized film containing the organic group and the alkyl group is excellent in chemical resistance and durability.
Here, if the leaving group is especially a methyl group (-CH _3), the preferred content is defined as follows from the peak intensity in the infrared light absorption spectrum.

That is, in the infrared absorption spectrum of the plasma polymerized film, when the intensity of the peak attributed to the siloxane bond is 1, the intensity of the peak attributed to the methyl group is about 0.05 to 0.45. Preferably, it is about 0.1 or more and 0.4 or less, more preferably about 0.2 or more and 0.3 or less. When the ratio of the peak intensity of the methyl group to the peak intensity of the siloxane bond is within the above range, it is necessary and sufficient in the plasma polymerization film while preventing the methyl group from unnecessarily inhibiting the formation of the siloxane bond. Since a number of active hands are generated, sufficient adhesion occurs in the plasma polymerized film. In addition, the plasma polymerized film exhibits sufficient chemical resistance and durability due to the methyl group.
The silane-based plasma polymerized film is composed of, for example, a silane-based polymer such as polyorganosiloxane.

Further, among the polyorganosiloxanes, a plasma polymerized film mainly composed of a polymer of octamethyltrisiloxane is preferably used for the first base film 114. A plasma polymerized film mainly composed of a polymer of octamethyltrisiloxane is particularly excellent in adhesiveness. Moreover, since the raw material which has octamethyltrisiloxane as a main component is liquid at normal temperature and has an appropriate viscosity, there is also an advantage that it is easy to handle.
The first base film 114 and the second base film 115 as described above enhance the adhesion between the substrate 112 and the liquid repellent film 113.

However, in the conventional nozzle plate, peeling between the substrate and the liquid repellent film has been a problem. Even in the conventional nozzle plate, a base film is interposed in order to improve the adhesion between the substrate and the liquid repellent film, but at the interface between the substrate and the base film and the interface between the base film and the liquid repellent film. In some cases, peeling occurred and the liquid repellent film was lost.
In view of such problems, the present inventors have found the cause of peeling of the liquid-repellent film and have made extensive studies on the structure of the nozzle plate that suppresses peeling. The inventors have found that the above-mentioned problems can be solved by providing a base film of two or more layers and forming the base film from a plasma polymerized film, thereby completing the present invention.

  That is, it is considered that the peeling of the liquid repellent film is caused by a residual stress generated between the substrate and the liquid repellent film. This residual stress is associated with the difference in thermal expansion of the substrate, the base film, and the liquid repellent film, and is considered to increase according to the operation of the ink jet printer. As a result, interfacial peeling occurs with an increase in residual stress. Further, it is considered that the ink penetrates into the peeled portion, the peeled portion is amplified by repeated wiping, and the liquid repellent film is lost.

  On the other hand, in this embodiment, this residual stress can be relieved by interposing two layers of base films 114 and 115. The detailed mechanism is unknown, but each of the two layers of the underlying films 114 and 115 is composed of a plasma polymerized film having a relatively low Young's modulus, and at the interface between the two layers of the underlying films 114 and 115, It is thought that this is because a minute misalignment of the atomic arrangement that does not break occurs, and the residual stress is absorbed thereby. Thereby, even if an inkjet printer is used over a long period of time, an increase in residual stress is prevented, and the occurrence of interface peeling can be prevented. As a result, it is possible to improve the chemical resistance and durability of the nozzle plate 11 over a long period of time.

  Moreover, even if a hole such as a pinhole is generated in one layer by forming the base film into two or more layers, the defect of the base film can be surely eliminated by closing the hole with another layer. . In other words, since the base film is formed of a plasma polymerized film, it is inevitable that pores in the micrometer unit are formed although the film is formed relatively uniformly. In particular, the lower the thickness of the underlying film, the higher the probability of generating holes.

  However, the positions of the holes generated in the plasma polymerized film are not constant and are not considered to be regular. Therefore, by forming two or more base films, the holes generated in one layer can be reliably covered with other layers. For the reasons described above, according to the present invention, it is possible to reliably prevent the generation of holes that completely penetrate the two layers of the base films 114 and 115. As a result, it is possible to reliably prevent corrosion of the substrate 112 and peeling of the liquid repellent film 113 due to ink.

In addition, since the two layers of the underlying films 114 and 115 in the present invention are each composed of a plasma polymerized film that exhibits adhesiveness, the interface between them is firmly adhered. Therefore, even if a hole is generated in one layer of the base film, there is no possibility that ink or the like enters the interface around the hole, and as a result, peeling of the liquid repellent film 113 is reliably prevented.
The liquid repellent film 113 is formed by coupling a coupling agent to the upper surface of the second base film 115. This coupling agent will be described in detail later.
The average thickness of the liquid repellent film 113 is preferably about 1 μm to 1000 μm, and more preferably about 5 μm to 500 μm.

<Ink chamber substrate>
An ink chamber substrate 12 is joined below the nozzle plate 11.
The ink chamber substrate 12 is temporarily supplied with a plurality of ink chambers (cavities, pressure chambers) 121 and ink supplied from the ink cartridge 931 by the nozzle plate 11, the side wall (partition wall) 122, and the diaphragm 13 described later. A reservoir chamber 123 for storage and a supply port 124 for supplying ink from the reservoir chamber 123 to each ink chamber 121 are partitioned.

Each ink chamber 121 is formed in a strip shape (cuboid shape), and is disposed corresponding to each nozzle hole 111. Each ink chamber 121 is variable in volume by vibration of a diaphragm 13 described later, and the head 1 is configured to eject ink by this volume change.
As a base material for obtaining the ink chamber substrate 12, for example, a silicon single crystal substrate, various glass substrates, various plastic substrates and the like can be used. Since these substrates are general-purpose substrates, the manufacturing cost of the head 1 can be reduced by using these substrates.
The average thickness of the ink chamber substrate 12 is not particularly limited, but is preferably about 10 μm to 1000 μm, and more preferably about 100 μm to 500 μm.
Also, the volume of the ink chamber 121 is not particularly limited, but is preferably about 0.1 nL to 100 nL, and more preferably about 0.1 nL to 10 nL.

<Vibration plate>
On the other hand, a vibration plate 13 is bonded to the opposite side of the ink chamber substrate 12 from the nozzle plate 11.
Examples of the material constituting the diaphragm 13 include various metal materials, various resin materials, various glass materials, various ceramic materials, silicon materials, and the like, and a composite material combining one or more of these materials. Is also used.
Further, stainless steel is particularly preferable as the metal material, and polyphenylene sulfide (PPS) and aramid resin are particularly preferable as the resin material, and a laminate of these is more preferably used.

<Piezoelectric element>
A plurality of piezoelectric elements 14 are provided on the side of the vibration plate 13 opposite to the ink chamber substrate 12.
Each piezoelectric element 14 has a piezoelectric layer interposed between a pair of electrodes, and is disposed corresponding to the substantially central portion of each ink chamber 121. Each piezoelectric element 14 is electrically connected to a piezoelectric element drive circuit and is configured to operate (vibrate, deform) based on a signal from the piezoelectric element drive circuit.
Each piezoelectric element 14 functions as a vibration source, and the diaphragm 13 vibrates due to vibration of the piezoelectric element 14 and functions to instantaneously increase the internal pressure of the ink chamber 121.

(Operation of inkjet recording head)
The head 1 is not deformed in the piezoelectric layer when a predetermined ejection signal is not input via the piezoelectric element drive circuit, that is, when no voltage is applied between the pair of electrodes of the piezoelectric element 14. . For this reason, the vibration plate 13 is not deformed, and the volume of the ink chamber 121 is not changed. Therefore, no ink droplet is ejected from the nozzle hole 111.

On the other hand, in a state where a predetermined ejection signal is input via the piezoelectric element driving circuit, that is, in a state where a constant voltage is applied between the pair of electrodes of the piezoelectric element 14, the piezoelectric layer is deformed. As a result, the diaphragm 13 is greatly deflected, and the volume of the ink chamber 121 is changed. At this time, the pressure in the ink chamber 121 increases instantaneously, and ink droplets are ejected from the nozzle holes 111.
When the ejection of one ink is completed, the piezoelectric element driving circuit stops applying the voltage between the pair of electrodes. As a result, the piezoelectric element 14 returns almost to its original shape, and the volume of the ink chamber 121 increases. At this time, the pressure from the ink cartridge 931 to the nozzle hole 111 (pressure in the positive direction) acts on the ink. Therefore, air is prevented from entering the ink chamber 121 from the nozzle hole 111, and an amount of ink corresponding to the amount of ink discharged is supplied from the ink cartridge 931 (reservoir chamber 123) to the ink chamber 121.

In this way, by sequentially inputting the ejection signal to the piezoelectric element 14 at the position to be printed in the head 1 via the piezoelectric element driving circuit, it is possible to print a desired character or figure.
In the present embodiment, the liquid repellent film 113 is shown as being formed on the entire surface of the substrate 112 on the ink droplet ejection side. However, the present invention is not limited to this, and the liquid repellent film 113 is formed on the substrate. It suffices to form at least a region surrounding the periphery of the nozzle hole 111 on the surface of the ink droplet discharge side 112. Even in such a configuration, the above-described effects are preferably exhibited.

(Nozzle plate manufacturing method)
Next, a manufacturing method of the nozzle plate 11 (a manufacturing method of the nozzle plate of the present invention) will be described.
The manufacturing method of the nozzle plate 11 includes a first step of forming two layers of base films 114 and 115 on the upper surface of the substrate 112 (surface on which ink droplets are ejected) by plasma polymerization, and a second base film A second step of applying energy to the upper surface of 115, a third step of forming the liquid-repellent film 113 on the upper surface of the second base film 115, and a second step of heating the second base film 115 and the liquid-repellent film 113. 4 steps. Hereinafter, each step will be described.

[1] First, prior to the formation of the two layers of base films 114 and 115, base processing is performed on the upper surface of the substrate 112.
Examples of the base treatment include physical surface treatment such as sputtering treatment and blast treatment, plasma treatment using oxygen plasma, nitrogen plasma, etc., corona discharge treatment, etching treatment, electron beam irradiation treatment, ultraviolet irradiation treatment, ozone Examples include chemical surface treatment such as exposure treatment, or a combination of these.

Next, a first base film 114 and a second base film 115 are formed in this order on the upper surface of the substrate 112 (first step).
The first base film 114 and the second base film 115 are formed by a plasma polymerization method.
The plasma polymerization method is a method in which a mixed gas of a source gas and a carrier gas is supplied in a strong electric field to polymerize molecules in the source gas and deposit a polymer on the upper surface of the substrate 112 to form a film. is there. According to this method, a very dense base film can be formed, so that moisture or the like can be prevented from penetrating the base film, for example.
Examples of the source gas include organosiloxanes such as methylsiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, decamethylcyclopentasiloxane, octamethylcyclotetrasiloxane, and methylphenylsiloxane.

On the other hand, for example, helium gas, argon gas, nitrogen gas or the like is used as the carrier gas.
The strong electric field is formed by applying a high frequency voltage to the electrode, and the output density of the high frequency voltage is preferably about 0.01 W / cm ² or more and 100 W / cm ² or less.

Further, the deposition is carried out under reduced pressure, the pressure is preferably about 133.3 × ¹⁰ -5 Pa or more 1333Pa less (1 × ¹⁰ -5 Torr or 10Torr or less), 133.3 × 10 ^- More preferably, it is about ⁴ Pa or more and 133.3 Pa or less (1 × 10 ⁻⁴ Torr or more and 1 Torr or less).
Here, the first base film 114 and the second base film 115 may be formed of plasma polymerization films having the same composition and structure, but may be different.

For example, the average thickness of the first base film 114 is preferably thicker than the average thickness of the second base film 115. Thereby, the stress relaxation function of the two layers of the underlying films 114 and 115 can be further enhanced.
Specifically, by increasing the thickness of the first base film 114, the first base film 114 is firmly adhered to the substrate 112, and the first base film 114 is used to The unevenness is absorbed, and the upper surface of the first base film 114 is a highly smooth surface. As a result, the substrate 112 and the first base film 114 and the first base film 114 and the second base film 115 are in close contact with each other. Peeling can be reliably prevented.

The average thickness of the first base film 114 is not particularly limited, but is preferably 1 nm to 1000 nm, and more preferably 2 nm to 800 nm.
Although the difference between the average thickness of the first base film 114 and the average thickness of the second base film 115 is not particularly limited, the average thickness of the first base film 114 is A, and the second base film When the average thickness of 115 is B, B is preferably 0.1 A or more and 0.8 A or less, and more preferably 0.2 A or more and 0.6 A or less.

On the other hand, the crystallinity of the first base film 114 is preferably higher than the crystallinity of the second base film 115. As a result, the first base film 114 has a relatively high rigidity, and can be firmly adhered to the substrate 112. Further, the second base film 115 has a relatively low rigidity, and the rigidity is close to that of the liquid repellent film 113 made of the coupling agent.
That is, if the degree of crystallinity of each film is as described above, the rigidity of each part of the substrate 112, the first base film 114, the second base film 115, and the liquid repellent film 113 is reduced from the substrate 112 side to the liquid repellent film. It becomes the structure which changes continuously so that it may fall gradually to 113 side. This is because the rigidity of the substrate 112 is generally high and the rigidity of the liquid repellent film 113 is generally low. Such a structure in which the rigidity gradually changes is suitable for the relaxation of the residual stress, and can prevent the peeling of the liquid repellent film 113 with certainty.

Note that the difference between the crystallinity of the first base film 114 and the crystallinity of the second base film 115 is preferably 5% or more and 50% or less, and is preferably 10% or more and 40% or less. Is more preferable. Thereby, the effect mentioned above becomes more remarkable.
Further, in order to make the crystallinity of the first base film 114 and the second base film 115 different, the formation conditions for forming the plasma polymerization film may be made different.

Examples of the formation conditions include a high-frequency power density during plasma polymerization, a distance between a pair of electrodes to which a high-frequency voltage is applied, and the like.
Of these, the crystallinity of the plasma polymerized film can be increased by increasing the power density, and the crystallinity of the plasma polymerized film can be decreased by decreasing the power density.
Further, the crystallinity of the plasma polymerized film can be increased by decreasing the distance between the electrodes, and the crystallinity of the plasma polymerized film can be decreased by increasing the distance between the electrodes.

Note that when the second base film 115 is formed after the first base film 114 is formed, it is preferable to temporarily stop the film formation so as to leave a certain time. As a result, the generated plasma is reset once. Therefore, even if a pinhole is generated in the first base film 114, the probability of being covered by the second base film 115 is increased.
In addition, after the formation of the first base film 114, energy may be applied to the upper surface of the first base film 114 as in [2] below. As a result, the adhesion between the first base film 114 and the second base film 115 is further improved.

  In this case, after the first base film 114 is formed and before the second base film 115 is formed, the source gas is not supplied, but only the carrier gas is supplied to generate plasma. Energy can be applied to the upper surface of one base film 114. According to this method, energy can be applied using a plasma polymerization apparatus without providing a separate energy applying means, so that the adhesion between the underlying films 114 and 115 can be easily increased.

In addition, since the plasma polymerization method is usually performed in a vacuum chamber, according to the above method, there is no possibility that the upper surface of the first base film 114 is exposed to the outside air. Therefore, the upper surface of the first base film 114 can be protected from contamination, moisture adhesion, and the like, and the adhesion between the first base film 114 and the second base film 115 can be improved.
Furthermore, when forming at least one of the first base film 114 and the second base film 115, the plasma polymerization conditions may be changed over time during the film formation. As a result, the characteristics of the plasma polymerization film are continuously changed.

For example, if the high frequency output density is reduced with time from the start of film formation, the rigidity of the plasma polymerized film will gradually decrease, and the adhesion to the substrate and the relaxation of the residual stress will be highly enhanced. A compatible undercoat film can be obtained.
Similarly, if the inter-electrode distance of the high-frequency voltage is increased with time from the start of film formation, the rigidity of the plasma polymerized film gradually decreases.

[2] Next, energy is applied to the upper surface of the second base film 115 (second step). When energy is applied, adhesiveness is developed on the upper surface of the second base film 115 and adhesion with the liquid repellent film 113 is improved.
Examples of a method for applying energy to the second base film 115 include a method of irradiating energy rays, a method of heating, a method of applying compressive force (physical energy), and exposure to plasma (applying plasma energy). And a method of exposing to ozone gas (applying chemical energy).

Examples of energy rays include electromagnetic waves such as ultraviolet rays and X-rays, particle beams such as electron beams and ion beams, and the like.
Among these, it is preferable to irradiate ultraviolet rays having a wavelength of 126 nm to 300 nm. According to such ultraviolet rays, adhesiveness can be expressed in a shorter time while preventing a significant deterioration in the characteristics of the second base film 115.

The time for irradiation with ultraviolet rays is not particularly limited, but is preferably 0.5 minutes or more and 30 minutes or less, and more preferably 1 minute or more and 10 minutes or less.
A hydroxyl group (OH group) is introduced into the upper surface of the second base film 115 to which energy is applied and activated in this manner. Note that the above-mentioned “activate” means a state in which a hydroxyl group is bonded to the upper surface of the second base film 115 as described above.

[3] Next, a coupling agent is supplied to the upper surface of the second base film 115. Thereby, a liquid repellent film is formed (third step).
The coupling agent may be supplied by any method, but a method of bringing a treatment solution containing the coupling agent into contact with the upper surface of the second base film 115 is preferably used. This contact is performed by a method of applying a treatment solution on the upper surface of the second base film 115, a method of immersing the substrate 112 on which the second base film 115 is formed in the treatment solution, or a treatment on the upper surface of the second base film 115. This can be done by spraying the solution.

  As the coupling agent, for example, various metal alkoxides having Ti, Li, Si, Na, K, Mg, Ca, St, Ba, Al, In, Ge, Bi, Fe, Cu, Y, Zr, Ta, etc. Of these, metal alkoxides having Si, Ti, Al, Zr and the like are generally used, and silane coupling agents (metal alkoxides) having Si are particularly preferably used. Silane coupling agents are inexpensive and easily available.

Here, the silane coupling agent has a general formula Rf _n SiX _(4-n) (where X is a hydrolyzable group that generates a silanol group by hydrolysis, and Rf is a functional group having various characteristics. N is an integer of 1 or more and 3 or less.
The weight average molecular weight of the functional group of the first coupling agent is preferably about 200 or more and 4000 or less, and more preferably about 1000 or more and 2000 or less.

Various solvents are used as the solvent for dissolving the first coupling agent, and for example, aromatic hydrocarbon solvents such as toluene, xylene, trimethylbenzene, tetramethylbenzene, and cyclohexylbenzene can be used. .
The concentration of the coupling agent in this treatment solution is preferably about 0.01% by weight to 0.5% by weight, more preferably about 0.1% by weight to 0.3% by weight.

When the coupling agent is supplied in this manner, the hydrolyzing group of the coupling agent is hydrolyzed to generate a silal group. The silal group and the hydroxyl group exposed on the upper surface of the second base film 115 are bonded by hydrogen bonding, and a coupling agent is introduced into the upper surface. As a result, a liquid repellent film 113 made of a coupling agent is formed.
According to such a method, since the coupling agents spontaneously align to form a film, a very dense liquid repellent film 113 can be obtained. The dense liquid repellent film 113 naturally has high liquid repellency and contributes to the improvement of the performance of the ink jet recording head 1.

Further, since the plasma polymerized film is a dense film as described above, hydroxyl groups that can be bonded to silar groups are exposed at high density on the surface. Even in this respect, the liquid repellent film 113 can be said to be a very dense film.
Note that the time for which the treatment solution is in contact with the upper surface of the second base film 115 is preferably about 0.1 second to 180 seconds, and more preferably about 10 seconds to 60 seconds.

Moreover, it is preferable that the temperature of a process solution is about 10 to 200 degreeC, and it is more preferable that it is about 20 to 100 degreeC.
In the step, the first base film 114 and the second base film 115 formed by the plasma polymerization method are formed not only on the upper surface of the substrate 112 but also on the inner surface of the nozzle hole 111. . As a result, the first base film 114, the second base film 115, and the liquid repellent film 113 are also formed on the inner surface of the nozzle hole 111.

Such a nozzle plate 11 enables ink droplets to be ejected to a normal position in order to improve the fluidity of ink in the nozzle hole 111. As a result, the print quality can be further improved.
It should be noted that the portion where the inner surface of the nozzle hole 111 and the upper surface of the substrate 112 intersect is a portion where the liquid repellent film 113 needs to be formed at the corner and is easily peeled in shape. By interposing 115, the adhesion of the liquid repellent film 113 at the corners can also be enhanced.

[4] Next, the second base film 115 and the liquid repellent film 113 are heated as necessary (fourth step). Thereby, hydrolysis is promoted between the second base film 115 and the liquid repellent film 113, and the liquid repellent film 113 is more firmly fixed.
The heating condition is preferably about 50 ° C. or higher and 450 ° C. or lower × 10 seconds or longer and 150 seconds or shorter, more preferably about 100 ° C. or higher and 250 ° C. or lower × 50 seconds or longer and about 100 seconds or shorter.

In addition, this heating is preferably performed in a humidified atmosphere. Thereby, further promotion of hydrolysis is achieved.
Furthermore, heat treatment (baking) at a temperature higher or longer than the above heating conditions is performed as necessary. As a result, the silal group and the hydroxyl group undergo dehydration condensation, and an extremely strong bond by a covalent bond is realized.
In this case, the heating atmosphere is a relatively dry inert gas atmosphere such as a nitrogen atmosphere.
The nozzle plate 11 is manufactured as described above.

Since the nozzle plate 11 manufactured in this manner effectively absorbs residual stress at the interface between the two layers of the base films 114 and 115 as described above, the substrate 112 and the two layers of the base films 114 and 115 are used. Further, it is possible to reliably prevent peeling at the interface between the respective portions of the liquid repellent film 113.
In particular, since each of the base films 114 and 115 is composed of a dense plasma polymerized film, moisture can be reliably prevented from entering, and the dense liquid repellent film 113 can be formed through the hydroxyl groups exposed at high density. Enable. Moreover, since the plasma polymerized film expresses adhesiveness by applying energy, it can more reliably prevent peeling at each interface.

In addition, by providing the two layers of the base films 114 and 115, it is possible to prevent the generation of holes penetrating them and reliably prevent the substrate 112 from being corroded by the ink and the liquid repellent film 113 from being peeled off.
The nozzle plate 11 exhibiting the effects as described above is improved in chemical resistance and durability over a long period of time, and can eject ink droplets normally.

Further, the ink jet recording head 1 and the ink jet printer 9 having such a nozzle plate 11 can perform high-quality printing over a long period of time.
Although the nozzle plate, the nozzle plate manufacturing method, the droplet discharge head, and the droplet discharge device of the present invention have been described based on the illustrated embodiments, the present invention is not limited to these.

For example, in the manufacturing method of the nozzle plate of this invention, it is not limited to the structure of the said embodiment, The process for arbitrary objectives may be added 1 or 2 or more.
In the above-described embodiment, the piezoelectric ink jet recording head has been described as an example. However, the droplet discharge head is not limited to such a configuration, and may be a head of a thermal method, an electrostatic actuator method, or the like.

Next, specific examples of the present invention will be described.
1. Production of inkjet recording head (Example 1)
<1> First, a silicon substrate serving as a base material for the nozzle plate was prepared, and surface treatment with oxygen plasma was performed on the surface thereof.
Next, the substrate was placed in a vacuum chamber of a plasma polymerization apparatus, and a plasma polymerization film having an average thickness of 150 nm was formed. The film forming conditions are as shown below.

<Film formation conditions>
-Source gas composition: Octamethyltrisiloxane-Source gas flow rate: 50 sccm
Carrier gas composition: Argon Carrier gas flow rate: 100 sccm
・ High frequency power output: 100W
・ High frequency output density: 25 W / cm ²
-Chamber pressure: 1 Pa (low vacuum)
・ Processing time: 15 minutes ・ Substrate temperature: 20 ° C.
As a result, a first base film was formed.

<2> Next, after the generation of plasma was stopped for about 1 minute, a plasma polymerization film having an average thickness of 150 μm was formed on the first base film under the same film formation conditions as above except for the processing time. . As a result, a second base film was formed.
<3> Next, the upper surface of the obtained second base film was irradiated with ultraviolet rays under the following conditions.
<Ultraviolet irradiation conditions>
-Atmospheric gas composition: Air (air)
・ Atmospheric gas temperature: 20 ℃
・ Atmospheric gas pressure: Atmospheric pressure (100 kPa)
UV wavelength: 172 nm
・ UV irradiation time: 5 minutes

<4> On the other hand, a glass substrate was attached to the lower surface of the substrate.
Then, a silane coupling agent having liquid repellency (“KY-130” manufactured by Shin-Etsu Silicone Co., Ltd.) is dissolved in FR thinner (manufactured by Shin-Etsu Silicone Co., Ltd.) so as to be 0.1% by weight. Prepared.
Next, a silicon substrate with a glass substrate attached was immersed in the treatment solution, and then pulled up at a constant speed. Thereby, the silane coupling agent was introduced into the upper surface of the second underlayer. The conditions of the treatment solution are as shown below.

<Processing solution conditions>
-Temperature of treatment solution: 25 ° C
・ Immersion time: 60 seconds ・ Pulling speed: 60 mm / second Thereby, a liquid repellent film was formed.

<5> Next, the silicon substrate on which the liquid repellent film was formed was subjected to heat treatment under the following conditions.
<Conditions for heat treatment>
-Heating atmosphere: humidified air-Heating temperature: 100 ° C
・ Heating time: 60 seconds

<6> Subsequently, baking treatment was performed at a higher temperature than the heat treatment of <5>.
<Conditions for baking treatment>
-Heating atmosphere: Nitrogen gas-Heating temperature: 200 ° C
-Heating time: 90 seconds As described above, a two-layer base film and a liquid repellent film were formed on the surface of a silicon substrate to obtain a nozzle plate.

(Example 2)
A nozzle plate was obtained in the same manner as in Example 1 except that the average thickness of the second base film was changed to 50 μm.
(Example 3)
A nozzle plate was obtained in the same manner as in Example 1 except that the conditions for forming the second base film were changed as follows.
・ High frequency output density: 15 W / cm ²
The crystallinity of the obtained second base film was approximately 10% lower than the crystallinity of the first base film.

Example 4
A nozzle plate was obtained in the same manner as in Example 1 except that the conditions for forming the second base film were changed as follows.
・ High frequency output density: 15 W / cm ²
・ Processing time: 10 minutes ・ Average thickness: 50 nm
The crystallinity of the obtained second base film was approximately 10% lower than the crystallinity of the first base film.

(Example 5)
In step <2>, a nozzle plate was obtained in the same manner as in Example 1 except that the raw material gas was not supplied but only the carrier gas was supplied to generate plasma and plasma treatment was performed for 1 minute.
(Comparative Example 1)
A nozzle plate was obtained in the same manner as in Example 1 except that instead of the two-layer base film, a single-layer base film formed by the following method was used.
A SiO ₂ film was formed on the top surface of a silicon substrate using a CVD apparatus under the following conditions.

-Source gas: dichlorosilane + oxygen-Substrate heating temperature: 650 ° C
・ Substrate heating time: 40 minutes ・ Average thickness: 200 μm
As a result, a base film of SiO ₂ film was obtained on the substrate.
(Comparative Example 2)
A nozzle plate was obtained in the same manner as in Example 1 except that the formation of the second base film was omitted.

2. 2. Evaluation of Nozzle Plate 2.1 Alkaline Immersion Test The following immersion test was performed on the nozzle plates obtained in the examples and comparative examples.
In the immersion test, after the nozzle plate is immersed in an alkaline solution, the substrate is taken out from the alkaline solution. At this time, the alkaline solution adhering to the film is repelled to form droplets having a contact angle of 90 ° or more. The time to be measured was measured.
In addition, each condition at the time of immersing a board | substrate in an alkaline solution is as showing below.

Alkaline solution: 0.01N NaOH aqueous solution (pH: 12)
-Temperature of alkaline solution: 80 ° C
-Immersion time: 1 second, 20 minutes, 3 hours And the time measured as described above was evaluated according to the following four criteria for each immersion time.
A: A droplet was formed within 20 seconds.
A: A droplet was formed in 21 to 60 seconds.
Δ: A droplet was formed in 61 to 180 seconds.
X: A droplet having a contact angle of 90 ° or more is not formed.

2.2 Wiping Test Next, the following wiping tests were performed on the nozzle plates obtained in the respective Examples and Comparative Examples.
First, a wiping operation (friction operation) with a cloth wiper was repeatedly performed on the liquid repellent film forming surface of the nozzle plate. Each time the wiping operation was performed 20000 times, 40000 times, and 60000 times, each was immersed in the above-described alkaline solution for 1 second, and then the droplet formation time was measured and evaluated according to the above-described criteria.
The evaluation results of 2.1 and 2.2 are shown in Table 1 below.

  As is clear from Table 1, the nozzle plate obtained in each example maintained excellent liquid repellency even when immersed in an alkaline solution for a long time in an alkaline immersion test. In addition, the liquid repellency was maintained even after a long wiping operation.

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording head 11 ... Nozzle plate 111 ... Nozzle hole 112 ... Substrate 113 ... Liquid-repellent film 114 ... First undercoat film 115 ... Second undercoat film 12 ... Ink chamber substrate 121 ... Ink chamber 122 ... Side wall 123 ... Reservoir chamber 124 ... Supply port 13 ... Vibration plate 131 ... Communication hole 14 ... Piezoelectric element 21 ... Plate 9 ... Inkjet printer 92 ... Main body 921 ... Tray 922 …… Discharge port 93 …… Head unit 931 …… Ink cartridge 932 …… Carriage 94 …… Printing device 941 …… Carriage motor 942 …… Reciprocating mechanism 943 …… Carriage guide shaft 944 …… Timing belt 95… ... Feeding device 951 ... Feeding motor 952 ... Feeding roller 52a ...... driven roller 952b ...... drive roller 96 ...... controller 97 ...... operation panel P ...... recording paper

Claims (10)

A substrate formed with a plurality of nozzle holes for discharging droplets and a surface of the substrate on the side for discharging droplets are provided so as to surround at least the periphery of the nozzle holes, and are composed of a coupling agent. A liquid repellent film,
A nozzle plate comprising a base film of two or more layers provided between the substrate and the liquid repellent film and formed of a plasma polymerization film. As the base film of the two or more layers, it has a first base film and a second base film located on the liquid repellent film side from this,
2. The nozzle plate according to claim 1, wherein the first base film has an average thickness larger than that of the second base film.   The nozzle plate according to claim 2, wherein the first base film has a crystallinity higher than that of the second base film.   The nozzle plate according to any one of claims 1 to 3, wherein the plasma polymerized film includes a Si skeleton including a siloxane bond and a leaving group bonded to the Si skeleton and including an organic group.   The nozzle plate according to claim 4, wherein the plasma polymerized film is mainly composed of polyorganosiloxane. A nozzle having a substrate on which a plurality of nozzle holes for discharging droplets are formed, and a liquid repellent film provided on the surface of the substrate on the side for discharging droplets so as to surround at least the periphery of the nozzle holes A method of manufacturing a plate,
A first step of forming a base film of two or more layers by a plasma polymerization method on the surface of the substrate on which the droplets are to be discharged;
A second step of applying energy to the surface of the base film;
And a third step of forming a liquid repellent film by supplying a coupling agent to the surface of the base film.   The method for manufacturing a nozzle plate according to claim 6, wherein when forming the base film of two or more layers in the first step, the film forming conditions by the plasma polymerization method are different for each layer.   Furthermore, the manufacturing method of the nozzle plate of Claim 6 or 7 which has a 4th process of heating the said base film and the said liquid-repellent film.   A droplet discharge head comprising the nozzle plate according to claim 1.   A droplet discharge apparatus comprising the droplet discharge head according to claim 9.

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