JP2011189260A - Droplet discharge apparatus and method for manufacturing droplet discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a droplet discharge apparatus and a method for manufacturing the droplet discharge apparatus having excellent discharge performance of air bubbles. <P>SOLUTION: The droplet discharge apparatus includes: a flow channel for supplying a discharged liquid; a liquid chamber communicating with the flow channel; nozzle holes communicating with the liquid chamber; and a pressurizer for pressurizing the discharge liquid housed in the liquid chamber. At least one type chosen from the group consisting of the flow channel, the liquid chamber and the nozzle holes wherein an arithmetic average roughness Ra of a surface in contact with the discharge liquid is ≥0.3 μm and ≤5 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge device and a method for manufacturing the droplet discharge device.

In recording devices such as consumer printers, film forming devices used in the manufacture of liquid crystal display devices and semiconductor devices, etc., discharge liquids such as ink and film materials are made into droplets and discharged toward the target. There is known a droplet discharge device that performs coloring and film formation.
In the discharge liquid used in the droplet discharge device, there is a dissolved gas in which the surrounding atmosphere is dissolved. Therefore, when the dissolved gas reaches a supersaturated state due to a change in temperature or pressure in the surrounding environment, bubbles are generated in the discharge liquid. In addition, bubbles may be mixed in the discharge liquid when replacing the discharge liquid container (for example, an ink cartridge).

If such bubbles remain in the droplet discharge device, the pressure for discharging the discharge liquid is attenuated by the bubbles, and the discharge characteristics may deteriorate.
Therefore, a technique for removing bubbles in the discharged liquid has been proposed (see, for example, Patent Document 1).
According to the technique disclosed in Patent Document 1, bubbles contained in the discharge liquid can be smoothly removed.
However, the technique disclosed in Patent Document 1 removes bubbles from the inside of the droplet discharge device in the circulating discharge liquid flow, and discharges the bubbles together with the discharge liquid from the discharge port of the buffer tank. .
For this reason, the entire apparatus becomes large and the manufacturing cost increases. It is also necessary to remove bubbles from the discharged discharge liquid.

JP 2008-246843 A

  The present invention provides a droplet discharge device and a method for manufacturing the droplet discharge device that are excellent in bubble discharge performance.

  According to one aspect of the present invention, a pressure is applied to the discharge liquid stored in the liquid chamber, the flow path for supplying the discharge liquid, the liquid chamber communicating with the flow path, the nozzle hole communicating with the liquid chamber, and the liquid chamber. A pressurizing means for applying, and an arithmetic average roughness Ra of a surface in contact with at least one kind of the discharge liquid selected from the group consisting of the flow path, the liquid chamber, and the nozzle hole is 0.3 μm or more, There is provided a droplet discharge device characterized by being 5 μm or less.

  According to another aspect of the present invention, a flow path for supplying a discharge liquid, a liquid chamber communicating with the flow path, a nozzle hole communicating with the liquid chamber, and a discharge accommodated in the liquid chamber A method of manufacturing a droplet discharge device, comprising: a pressurizing unit that applies pressure to the liquid; and at least one type of the discharge liquid selected from the group consisting of the flow path, the liquid chamber, and the nozzle hole; Provided is a method for manufacturing a droplet discharge device, wherein the contact surface has an arithmetic average roughness Ra of 0.3 μm or more and 5 μm or less.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the droplet discharge device excellent in bubble discharge | emission property and a droplet discharge device is provided.

It is a schematic cross section for illustrating the droplet discharge device concerning this embodiment. It is a schematic external view of a droplet discharge device. It is a model perspective view for illustrating a bubble discharge experiment device. It is a schematic diagram for illustrating the procedure of the bubble discharge experiment. It is a schematic process diagram for illustrating a manufacturing method of a droplet discharge device. FIG. 3 is a schematic cross-sectional view for illustrating a “thermal type” droplet discharge device.

Hereinafter, embodiments of the present invention will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
FIG. 1 is a schematic cross-sectional view for illustrating a droplet discharge device according to the present embodiment. 1 is an enlarged view of a cross section in the AA direction of FIG.
FIG. 2 is a schematic external view of the droplet discharge device.
As illustrated in FIG. 2, the droplet discharge device 1 is a so-called multi-nozzle type droplet discharge device including a plurality of nozzle holes 12.
Here, the driving method of the droplet discharge device 1 includes a “thermal type” that generates bubbles by heating and discharges the discharge liquid by utilizing the film boiling phenomenon, and a discharge liquid that uses the bending displacement of the piezoelectric element. There is a “piezoelectric type” to be discharged, but as an example, here, “piezoelectric type” is taken as an example.

As shown in FIG. 1, the droplet discharge device 1 includes a flexible film 3 provided on one end face of a nozzle body 11 and a piezoelectric element 4 provided on the surface of the flexible film 3. Yes. In the case of the “piezoelectric type”, the flexible film 3 and the piezoelectric element 4 serve as a pressurizing unit that applies pressure to the discharge liquid stored in the liquid chamber 9. In this case, the piezoelectric element 4 is piezoelectric in the axial direction of the liquid chamber 9 (the one illustrated in FIG. 1 is just above the liquid chamber 9) so that the pressure wave due to the bending displacement of the piezoelectric element 4 is easily transmitted to the discharge liquid in the liquid chamber 9. It is preferable to provide the element 4.
The piezoelectric element 4 is obtained by stacking the lower member 6, the drive electrode 7, the upper member 5, and the drive electrode 8 in this order and then firing them integrally. The piezoelectric element 4 thus integrally fired has high strength and is easy to handle.

The nozzle body 11 is provided with a flow path 10 that opens to one end face, and the flexible film 3 is provided so as to cover the opening of the flow path 10.
One end of a plurality of liquid chambers 9 communicates with the side of the flow path 10 facing the opening. A flat portion 9a is provided at the other end of the liquid chamber 9 (the end on the side where the nozzle hole 12 is provided). The flat portion 9 a is provided so as to be substantially parallel to the other end face of the nozzle body 11. A tapered portion 12a provided at one end of the nozzle hole 12 is opened in the flat portion 9a, and the liquid chamber 9 and the nozzle hole 12 communicate with each other through the tapered portion 12a. The other end of the nozzle hole 12 opens to the end surface of the nozzle body 11. Here, since the volume of the taper portion 12a is small, it can be regarded as a part of the nozzle hole 12. Therefore, the dimension from the flat portion 9a (the end surface of the liquid chamber 9) to the end surface of the nozzle body 11 can be the nozzle length L.
That is, the nozzle body 11 is provided with a flow path 10 for supplying a discharge liquid, a liquid chamber 9 that communicates with the flow path 10, and a nozzle hole 12 that communicates with the liquid chamber 9.

  The material of the nozzle body 11 can be stainless steel or nickel alloy, and the material of the flexible film 3 can be polyethylene terephthalate. The material of the lower member 6 and the upper member 5 of the piezoelectric element 4 can be piezoelectric ceramics (for example, lead zirconate titanate), and the drive electrodes 7 and 8 can be copper alloys. . However, these materials are not limited to those illustrated, and various modifications are possible. For example, the material of the nozzle body 11 can be appropriately selected from a resin, a metal, a semiconductor material, and the like that have corrosion resistance to the discharged liquid to be discharged.

  As an example of the dimensions of the main part of the droplet discharge device 1, the thickness of the nozzle body 11 is about 1 mm to several mm, and the cross-sectional shape of the flow path 10 is about several mm in height (thinner than the height of the liquid chamber 9). The width of the nozzle hole 12 which is about several 100 μm wide, the cylindrical opening is about 20 μm to 50 μm, the diameter of the liquid chamber 9 is about 250 μm to 600 μm, the thickness of the flexible film 3 is about 10 μm, and the piezoelectric element 4 Can be about 30 μm thick.

  The nozzle length L is preferably 50 μm or more and 150 μm or less. This is because if the thickness is less than 50 μm, the strength in the vicinity of the opening portion of the nozzle hole is lowered, and there is a possibility that deformation in the vicinity of the opening portion may occur due to an increase in the internal pressure during droplet discharge. Further, if it exceeds 150 μm, it is not preferable from the viewpoints of nozzle hole processability and increase in discharge resistance.

  When the diameter of the nozzle hole 12 is 1, the diameter of the liquid chamber 9 is preferably 5 or more and 30 or less. Moreover, it is more preferable to set it as 8 or more and 20 or less. If it exceeds 30, the pressure receiving area becomes too large, and a large force acts in the vicinity of the opening due to an increase in the internal pressure when the droplet is ejected. If it is less than 5, it becomes difficult to increase the processing accuracy in the depth direction of the liquid chamber 9 (positional accuracy of the flat portion 9a), and further, the concentricity of the liquid chamber 9 and the nozzle hole 12 can be secured. This is because it is not easy, and problems arise in operation characteristics such as landing characteristics and flight characteristics.

  In the present embodiment, the arithmetic average roughness Ra of the surface in contact with the discharge liquid of the element provided in the droplet discharge device 1 is 0.3 μm or more and 5 μm or less. For example, the arithmetic average roughness Ra of the surface in contact with at least one type of discharge liquid selected from the group consisting of the flow path 10, the liquid chamber 9, and the nozzle hole 12 is 0.3 μm or more and 5 μm or less. When the flow path 10 includes a restrictor plate (not shown) having a restrictor, the arithmetic average roughness Ra of the surface of the restrictor plate that contacts the discharge liquid is 0.3 μm or more and 5 μm or less. Details of the arithmetic average roughness Ra of the surface in contact with the discharge liquid will be described later.

The arrangement and shape of each element provided in the droplet discharge device 1 are not limited to those illustrated in FIG. 1, and various changes can be made.
For example, each liquid chamber 9 may be in communication with a dedicated channel. Further, in terms of the structure of the piezoelectric element 4, the lower member 6 is a diaphragm, and the upper member 5 is a piezoelectric body, but is not limited thereto. Also, various driving methods that cause displacement can be employed. Moreover, although the cross-sectional shape of the flow path 10 is rectangular in FIG. 1, it is not limited to this, and may have rounded corners.

Here, bubbles generated in the discharge liquid due to temperature change or pressure change in the surrounding environment or mixed in the discharge liquid when replacing a discharge liquid container (not shown) stay in the droplet discharge device 1. Then, since the pressure for discharging the discharge liquid is attenuated by the bubbles, the discharge characteristics may be deteriorated.
As a result of the study, the present inventor, when the surface roughness of the surface in contact with the discharge liquid of the element provided in the droplet discharge device is within a predetermined range, discharge of bubbles staying in the droplet discharge device is prevented. I got the knowledge that it can be encouraged.
Next, the knowledge obtained by the present inventor regarding the relationship between the surface roughness of the surface in contact with the discharged liquid and the bubble dischargeability will be described.
FIG. 3 is a schematic perspective view for illustrating a bubble discharge experiment apparatus.
FIG. 4 is a schematic diagram for illustrating the procedure of the bubble discharge experiment.

As shown in FIG. 3, the discharge experiment apparatus 100 is provided with a base 101 and a lid 102.
The base portion 101 has a plate shape and is provided with a groove portion 101a extending in the longitudinal direction. The length of the groove 101a in the longitudinal direction is about 5 cm, and the depth is about 1 mm. A hole 101b is provided in the vicinity of one end in the longitudinal direction of the groove 101a. The hole portion 101 b passes through the thickness direction of the base portion 101 and opens at the end surface of the base portion 101. The base 101 is made of stainless steel.

  And what changed arithmetic average roughness Ra of the surface of the groove part 101a was created, and the relationship between surface roughness and bubble discharge | emission property was verified. In this case, an arithmetic average roughness Ra of 0.1 μm, 0.3 μm, 0.5 μm, 1 μm, 5 μm, 7 μm, and 10 μm was prepared.

The lid portion 102 has a plate shape and is provided with a hole portion 102a communicating with the vicinity of the end of the groove portion 101a on the side opposite to the side where the hole portion 101b is provided. The hole 102 a passes through the thickness direction of the lid 102 and opens at the end surface of the lid 102. The lid 102 is made of transparent glass so that the movement of the bubbles 103 can be observed.
The hole 101b and the hole 102a serve as inlets when water and bubbles 103 are put into the groove 101a, and also serve as so-called air vent holes.
The base 101 and the lid 102 are joined so as to be liquid-tight. For example, the base 101 and the lid 102 can be joined with an adhesive so as to be liquid-tight. Further, before the base portion 101 and the lid portion 102 are joined, the organic matter or the like is decomposed and removed by performing ultraviolet cleaning of the groove portion 101a.

Next, the procedure of the bubble discharge experiment is illustrated.
First, as shown in FIG. 4A, the groove portion 101a was filled with water, and one bubble 103 having a diameter of about 1 mm was put therein.
Next, as shown in FIG. 4B, the discharge experiment apparatus 100 was tilted 45 °, and the movement of the bubbles 103 was observed through the lid portion 102 to evaluate the discharge properties of the bubbles 103.

As a result of the experiment using the discharge experiment apparatus 100 as described above, the bubble 103 remained stationary when the arithmetic average roughness Ra was 0.1 μm. Then, it was found that when the arithmetic average roughness Ra is 0.3 μm, the bubbles 103 start moving, and the moving speed increases as the arithmetic average roughness Ra increases.
That is, it has been found that if the arithmetic average roughness Ra of the surface in contact with the discharge liquid is set to 0.3 μm or more, the bubble discharge performance can be improved.

In addition, the present inventor conducted a discharge experiment using the droplet discharge device 1 based on this result.
That is, an element having an arithmetic average roughness Ra of 0.1 μm, 0.3 μm, 0.5 μm, 1 μm, 5 μm, 7 μm, and 10 μm is prepared on the surface of the droplet discharge device 1 that comes into contact with the discharged liquid. A discharge liquid discharge experiment was conducted. In this case, the discharge liquid was ink used in an inkjet printer or the like.

  As a result of the experiment using the droplet discharge device 1 as described above, it was confirmed that ink was discharged from all the nozzle holes 12 when the arithmetic average roughness Ra was 0.3 μm or more and 5 μm or less. On the other hand, when the arithmetic average roughness Ra was 0.1 μm, 7 μm, and 10 μm, it was confirmed that ink was not ejected from the nozzle holes 12 of about 3% to 6%.

  For this reason, in consideration of bubble discharge properties and discharge liquid discharge properties, the arithmetic average roughness Ra of the surface in contact with the discharge liquid of the elements provided in the droplet discharge device is 0.3 μm or more and 5 μm or less. It turned out to be preferable.

Next, the operation of the droplet discharge device 1 according to the present embodiment will be illustrated.
When a voltage is applied to the drive electrode 7 or the drive electrode 8, the upper member 5 undergoes a downward convex bending displacement, and accordingly, the laminated piezoelectric element 4 undergoes a downward convex bending displacement. This bending displacement presses the flexible film 3 downward and pressurizes the discharge liquid in the liquid chamber 9 toward the nozzle hole 12 as indicated by the wavy line in FIG. Therefore, the discharge liquid is discharged from the nozzle hole 12 according to the bending displacement.

  The discharge liquid reduced by discharge is replenished from a discharge liquid container (not shown) through the flow path 10. Since the bending displacement of the piezoelectric element 4 can be controlled by controlling the applied voltage, the discharge amount and the discharge timing can be controlled by controlling the applied voltage by a control device (not shown). In addition, the bending displacement of the piezoelectric element 4 is absorbed by the flexible film 3, and mutual interference between adjacent piezoelectric elements and pressure chambers is suppressed.

In the present embodiment, the element provided in the droplet discharge device 1 has an arithmetic average roughness Ra of 0.3 μm or more and 5 μm or less of the surface in contact with the discharge liquid.
For this reason, even if bubbles are generated in the discharge liquid due to temperature change or pressure change in the surrounding environment, or bubbles are mixed in the discharge liquid when replacing a discharge liquid container (not shown), It can promote discharge. Moreover, the discharge property of the discharge liquid can be improved together with the discharge property of the bubbles.
Further, it is not necessary to provide a device for circulating the discharge liquid in order to discharge the bubbles. Therefore, the entire apparatus does not become large and the manufacturing cost of the apparatus does not increase.
Further, since a special treatment such as a hydrophilic treatment is not required to improve the bubble discharge property, the bubble discharge property does not change due to changes over time, processing unevenness, and the like. In addition, since a special processing step such as a hydrophilic treatment is not required, the manufacturing process can be simplified and the manufacturing cost can be reduced.

Next, a method for manufacturing the droplet discharge device 1 according to the present embodiment will be illustrated.
FIG. 5 is a schematic process diagram for illustrating a method for manufacturing the droplet discharge device 1.
First, as shown in FIG. 5A, the outer periphery of the plate material is processed to create a so-called blank nozzle body 11.
Next, as shown in FIG. 5B, the flow path 10 is processed in the blank nozzle body 11. As the tool 19a used at this time, a tool suitable for cutting a groove can be used.

Next, as shown in FIG. 5C, the liquid chamber 9 is processed.
Although the tool 19b illustrated in FIG.5 (c) is a drill, it is not necessarily limited to this, The thing suitable for making a hole can be selected suitably. At this processing stage, a conical recess remains on the bottom side of the liquid chamber 9.
FIG. 5D shows a case where an end mill is used as the tool 19c for processing the liquid chamber 9. In this case, a conical convex portion remains on the bottom surface side of the liquid chamber 9.

  Next, as shown in FIG. 5E, the conical recesses and protrusions remaining on the bottom surface side of the liquid chamber 9 are removed to form a flat portion 9a. The tool 19d illustrated in FIG. 5 (e) has a flat tip and a cutting edge at the tip, but is not limited thereto, and the bottom of the liquid chamber 9 is flattened. Any material that can be processed may be used. Moreover, the processing method can also be selected as appropriate, and for example, it can be a die-cut electric discharge machining using a shaped electrode or a fine-hole pipe electric discharge machining.

Next, as shown in FIG. 5 (f), the nozzle hole 12 is drilled (center hole machining). This pilot hole machining (center hole machining) is performed to increase the machining accuracy of the nozzle holes 12. For example, the substantially V-shaped recess 29 can be processed using a tool 19e having a blade shape that is slightly larger in diameter than the nozzle hole 12 and protrudes in a substantially V-shape. Further, the recess 29 can be formed by plastic working so that the tool 19e is impacted without being rotated.
Next, as shown in FIG. 5G, the nozzle hole 12 is processed. At this time, since the tool 19f is guided by the centering action of the substantially V-shaped recess 29, the deflection of the tool 19f is suppressed. Moreover, since the so-called biting is improved, the machinability at the beginning of processing is also improved.
Next, finishing is performed as necessary so that the surface roughness of the surface in contact with the discharge liquid is within a predetermined range (arithmetic mean roughness Ra of 0.3 μm or more and 5 μm or less). For example, at least one selected from the group consisting of the flow path 10, the liquid chamber 9, and the nozzle hole 12 has an arithmetic average roughness Ra of a surface in contact with the discharge liquid of 0.3 μm or more and 5 μm or less.

  Next, as shown in FIG. 5 (h), the flexible film 3 is bonded so as to be liquid-tight so as to cover the flow path 10 of the nozzle body 11. Adhesion can be performed with, for example, an epoxy-based adhesive. Then, the piezoelectric element 4 is installed on the surface of the bonded flexible film 3. At this time, the piezoelectric element 4 is installed in the axial direction of the liquid chamber 9 (directly above in the case illustrated in FIG. 5H). The piezoelectric element 4 is manufactured in advance by laminating the lower member 6, the drive electrode 7, the upper member 5, and the drive electrode 8 in this order and then firing them integrally.

  In addition, the processing method shown in FIG. 5 is an illustration to the last, and is not necessarily limited to these. For example, in addition to the cutting process described above, various physical and chemical removal methods such as dry etching process, wet etching process, electric discharge process, laser process, and plastic process can be employed. Further, such processing methods can be appropriately combined as necessary.

Next, a droplet discharge apparatus according to another embodiment is illustrated.
FIG. 6 is a schematic cross-sectional view for illustrating a so-called “thermal type” droplet discharge device that discharges the discharge liquid by heating.
The droplet discharge device 32 includes a protective film 34 provided on one end face of the nozzle body 11 and a heating element 33 provided on the surface of the protective film 34. In the case of the “thermal type” droplet discharge device 32, the protective film 34 and the heating element 33 serve as a pressurizing unit that applies pressure to the discharge liquid stored in the liquid chamber 9. The heating element 33 is formed of a resistive thin film made of an electrical resistance material, and generates Joule heat when a voltage is applied from a voltage applying means (not shown). The protective film 34 is made of an inorganic material such as silicon oxide or silicon nitride. The protective film 34 can be about 2 μm thick, and the heating element 33 can be about 3 μm thick. However, these arrangements, shapes, dimensions, and materials are not limited to those illustrated in FIG. 6, and various changes can be made.

Next, the operation of the droplet discharge device 32 will be illustrated.
When a voltage is applied to the heating element 33 from a voltage applying means (not shown), the heating element 33 generates heat. Bubbles 35 are generated in the discharged liquid by the heat generated by the heating element 33. The discharged liquid in the liquid chamber 9 is pressurized toward the nozzle hole 12 by the pressure of the generated bubbles 35. Therefore, the discharge liquid is discharged from the nozzle hole 12 according to this pressure. The discharge liquid reduced by discharge is replenished from a discharge liquid container (not shown) through the flow path 10. The generated bubbles 35 disappear so as to contract because the surrounding discharge liquid loses heat. If the applied voltage is controlled in this series of processes, the size of the bubbles 35 and the timing of their generation can be controlled. Therefore, the applied voltage can be controlled by a control device (not shown) to control the discharge amount and the discharge timing. it can.
The manufacturing method of the droplet discharge device 32 is the same as that described above except that the flexible film 3 is replaced by the protective film 34 and the piezoelectric element 4 is replaced by the heat generating element 33, and therefore the description thereof is omitted.

  Note that the droplet discharge device 1 and the droplet discharge device 32 exemplified above are integrally provided with the liquid chamber 9, the flow path 10, the nozzle hole 12, and the like in the nozzle body 11, but are not limited thereto. is not. For example, the nozzle body 11 can be formed by joining a nozzle plate provided with the nozzle holes 12 and a member provided with the liquid chamber 9 and the flow path 10.

Moreover, the nozzle plate provided with the nozzle hole 12, the intermediate plate provided with the liquid chamber 9, and the housing provided with the flow path 10 can be joined.
Further, the present invention is not limited to the illustrated elements, and other elements may be provided. For example, a restrictor plate having a restrictor can be provided in the flow path 10.
When various elements are provided in the droplet discharge device, the arithmetic average roughness Ra of the surface in contact with the discharge liquid of each element can be set to 0.3 μm or more and 5 μm or less.

Heretofore, the present embodiment has been illustrated. However, the present invention is not limited to these descriptions.
As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention.
For example, the shape, size, material, arrangement, and the like of each element included in the droplet discharge device 1, the droplet discharge device 32, and the like are not limited to those illustrated, and can be changed as appropriate.
Moreover, each element with which each embodiment mentioned above is combined can be combined as much as possible, and what combined these is also included in the scope of the present invention as long as the characteristics of the present invention are included.

  DESCRIPTION OF SYMBOLS 1 Droplet discharge device, 3 Flexible film | membrane, 4 Piezoelectric element, 9 Liquid chamber, 10 Flow path, 11 Nozzle body, 12 Nozzle hole, 32 Droplet discharge device, 33 Heat generating element, 34 Protective film, 35 Bubble, 100 Ejection experiment device, 101 base, 102 lid

Claims (5)

A flow path for supplying a discharge liquid;
A liquid chamber that communicates with the flow path and stores the discharged liquid;
A nozzle hole that communicates with the liquid chamber and discharges the discharge liquid to the object;
Pressurizing means for applying pressure to the discharged liquid stored in the liquid chamber;
With
At least one selected from the group consisting of the flow path, the liquid chamber, and the nozzle hole has an arithmetic average roughness Ra of a surface in contact with the discharge liquid of 0.3 μm or more and 5 μm or less. Droplet discharge device. Further comprising a restrictor plate having a restrictor,
2. The droplet discharge device according to claim 1, wherein the restrictor plate has an arithmetic average roughness Ra of a surface in contact with the discharge liquid of 0.3 μm or more and 5 μm or less.   The droplet discharge device according to claim 1, wherein the pressurizing unit includes a piezoelectric element or a heating element.   The droplet discharge device according to claim 1, wherein the piezoelectric element or the heating element is provided in an axial direction of the liquid chamber. A flow path for supplying a discharge liquid;
A liquid chamber that communicates with the flow path and stores the discharged liquid;
A nozzle hole that communicates with the liquid chamber and discharges the discharge liquid to the object;
Pressurizing means for applying pressure to the discharged liquid stored in the liquid chamber;
A method for manufacturing a droplet discharge device comprising:
At least one selected from the group consisting of the flow path, the liquid chamber, and the nozzle hole has a step of setting an arithmetic average roughness Ra of a surface in contact with the discharge liquid to be 0.3 μm or more and 5 μm or less. A method for manufacturing a droplet discharge device.

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