JP2019171580A - Ink jet discharge method, method for manufacturing member, and ink jet discharge apparatus - Google Patents

Abstract

To provide an ink jet discharge method capable of preventing occurrence of satellite even if ink having a high viscosity is used, and a method for manufacturing a member including an ink jet coating step.SOLUTION: With an ink jet discharge method for discharging a liquid through a discharge flow path 100, a velocity V of the liquid discharged through the discharge flow path 100 is not less than 6 m/s and a Weber number We is not less than 14 nor more than 120 when a viscosity of the liquid is not less than 80 mPa s nor more than 350 mPa s.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an ink jet type discharge method and a discharge device using an ink jet technique for discharging a liquid to adhere to a target. Moreover, this invention relates also to the manufacturing method of the member provided with the coating film.

Ink jet technology is conventionally used for printing on paper, cloth, substrates, etc., and also for coating cases of electronic devices, and in recent years, its use has been expanded to the painting of automobile bodies and the like.
In the inkjet technology that forms dots (granular pixels) formed by droplets on the target of printing or painting by discharging liquid from the discharge head by a control command based on image data, satellites separated from the main droplets are generated. Affects the quality of printing or painting. The satellite is one or more small droplets that are generated when a portion connected to the rear of the front end portion (main droplet) of the discharged droplet is separated from the main droplet. The satellite is delayed from the main droplet and adheres to a position deviated from the dot formed by the main droplet, which may cause blurring of the pattern boundary, color unevenness, and the like.

  In Patent Document 1, in order to reduce the occurrence of satellites due to ink discharge, in addition to using slit-shaped discharge ports having a predetermined aspect ratio, the width of the slit, the surface tension of the liquid, and the density of the liquid It has been proposed that the number of Webers specified from the liquid discharge speed is 10 or less. This patent document 1 assumes printing of a high-definition photograph etc. by a very small amount of droplets.

Patent No. 4965972

Due to the expansion of the application target of inkjet technology, the use of ink having physical properties that are significantly different from those of inks used in conventional inkjet printing and inkjet coating is being studied.
For example, when performing inkjet coating of objects that are used in harsh environments such as aircraft bodies, ink used for inkjet printing or inkjet vehicle body coating is required because the ink used (paint) requires high weather resistance. The viscosity of the ink is higher than the water-based ink for use.

  When ink having a high viscosity is used as described above, according to the test by the inventors of the present invention, the Weber number of 10 or less as disclosed in Patent Document 1 is not necessarily effective in preventing satellite generation. It turns out that it is not.

  As described above, the present invention has an object to provide an inkjet discharge method, an inkjet discharge apparatus, and a method for manufacturing a member provided with a coating film that can prevent the generation of satellites even when ink having a high viscosity is used. And

  The present invention relates to an inkjet discharge method for discharging a liquid through a discharge channel, and when the viscosity of the liquid is 80 mPa · s or more and 350 mPa · s or less, the velocity of the liquid discharged through the discharge channel is 6 m / s or more, and the Weber number is 14 or more and 120 or less.

In the inkjet discharge method of the present invention, the volume of the liquid discharged through the discharge flow path is preferably 0.5 × 10 ³ pl or more and 20 × 10 ³ pl or less.

  In the inkjet discharge method of the present invention, in a state in which the liquid is pressurized to a predetermined pressure in the liquid chamber in which the liquid is placed, a valve that allows the liquid to pass from the liquid chamber toward the discharge flow path is opened It is preferable to set the valve opening time to be a time corresponding to the volume of the liquid discharged by the discharge flow path.

  In the inkjet discharge method of the present invention, it is preferable that the liquid is received from the liquid chamber containing the liquid and introduced into the discharge flow channel into the introduction flow channel having a larger cross-sectional area than the discharge flow channel.

In the inkjet discharge method of the present invention, the discharge channel has a circular cross section, the number of Webers is ρ as the density of the liquid, D as the diameter of the discharge port for discharging the liquid in the discharge channel, and discharged from the discharge port. It is preferable that (ρDV ² ) / σ be expressed as V where the liquid velocity is V and the surface tension of the liquid is σ.

  Moreover, this invention is a method of manufacturing a member, Comprising: The step which coats a member with the inkjet discharge method mentioned above is characterized by the above-mentioned.

  In the member manufacturing method of the present invention, it is preferable that the member constitutes an aircraft body.

  Furthermore, the present invention is an inkjet discharge apparatus, comprising: a liquid chamber in which a liquid having a viscosity of 80 mPa · s or more and 350 mPa · s or less is placed; and a discharge channel that is connected to the liquid chamber and discharges the liquid. The speed of the liquid discharged through the discharge flow path is 6 m / s or more, and the Weber number is 14 or more and 120 or less.

In the inkjet discharge device of the present invention, the volume of the liquid discharged through the discharge flow path is preferably 0.5 × 10 ³ pl or more and 20 × 10 ³ pl or less.

  In the inkjet discharge apparatus of the present invention, the volume of the discharge flow path is preferably smaller than the volume of the liquid.

The inkjet discharge device of the present invention further includes an introduction channel that receives liquid from the liquid chamber and flows into the discharge channel, the discharge channel has a circular cross section, and the introduction channel has a circular shape. It has a cross-section, has a larger cross-sectional diameter than the discharge flow path, and is arranged coaxially with the discharge flow path. The Weber number is the liquid density ρ, and the diameter of the discharge port that discharges the liquid in the discharge flow path. D is preferably represented by (ρDV ² ) / σ where V is the velocity of the liquid discharged from the discharge port and σ is the surface tension of the liquid.

According to the liquid discharge speed and the number of Webers specified in the present invention, liquid can be discharged through the discharge flow path even when using liquid such as highly viscous ink or paint, thereby preventing the occurrence of satellites. Can do.
According to the present invention, it is possible to overcome the impossibility of discharging when a large volume droplet is discharged using a high-viscosity liquid, so that it is possible to contribute to the practical use of inkjet coating of a large apparatus.

(A) is a figure which shows typically the ink chamber and discharge nozzle with which the header apparatus of the inkjet apparatus which concerns on embodiment of this invention is equipped. The header device is broken along the line Ia-Ia in (b). (B) is a schematic diagram which shows a discharge nozzle (flow path) from the direction shown by the Ib arrow of (a). (A)-(c) is a figure which shows typically an example of the state of the droplet until the ink discharged by the discharge nozzle reaches a target, respectively. Only in the example shown in (a) according to the embodiment, no satellite is generated. In the examples shown in (b) and (c) according to the comparative example, satellites are generated. In each of (a) to (c), the inner side of the rectangular frame corresponds to a plan view showing dots formed by ink droplets as landing targets. FIG. 5 is a graph plotting the speed and Weber number of ejected ink using high-viscosity ink and changing the nozzle diameter for each ink pressure (0.6 MPa / 0.4 MPa).

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
In the present embodiment, an inkjet ejection method and an inkjet ejection apparatus that can be applied when coating (or printing) a large area surface of a large structure such as an aircraft body by an inkjet technique will be described.

For the coating of the aircraft body surface according to the present embodiment, a liquid (ink, paint) having physical properties suitable for weather resistance required for aircraft operation is used. Hereinafter, the liquid used for painting in the present embodiment is referred to as “ink”.
Such inks have a very high viscosity compared to inks typically used for ink jet printing or ink jet painting. The viscosity of a typical ink remains at most about 10 mPa · s, whereas the viscosity of the ink used in this embodiment is 80 to 350 mPa · s. A more preferable viscosity of the ink is 86 to 189 mPa · s.

  In this embodiment, color coating is performed using a plurality of types of inks having different colors. For example, it is possible to realize an arbitrary pattern including a light and shade gradation by a halftone printing method using inks corresponding to each color of cyan, magenta, yellow, and black. Halftone printing reproduces the color tone according to the ratio of the color per unit area of dots formed by a single color ink droplet on the surface of an object. Each of the plurality of colors of ink has a viscosity within the above-described range of viscosity values.

FIG. 1A shows a part of the header device 10 provided in the ink jet apparatus used for the ink jet coating of the present embodiment. The header device 10 corresponds to an arbitrary ink color. The header device 10 is similarly configured for each of a plurality of ink colors.
The header device 10 is driven to a predetermined position by a control command (not shown) provided in the ink jet device according to a control command sent based on the image data, and ejects ink from the ejection nozzle 12. The header device 10 includes a plurality of header devices 10 for each color.

  The inkjet device of the present embodiment drives the header device 10 in a direction orthogonal to the direction of relative displacement between the inkjet device and the object to be coated while being relatively displaced with respect to the member that is the object to be coated, and the desired amount. Ink is ejected from the ejection nozzles 12 of the header device 10. Such an inkjet device includes a header device 10 corresponding to each color, a mechanism that drives the header device 10, a control unit, and a tank (not shown) that stores ink of each color.

With reference to FIGS. 1A and 1B, the configuration of the header device 10 will be briefly described. The header device 10 drives an ink chamber 11 into which ink is put, a discharge nozzle 12 that is connected to the ink chamber 11 and discharges ink, a valve 14 that closes an inlet 121 of the discharge nozzle 12, and the pin 14. The actuator 15 is provided.
Although only one discharge nozzle 12 is shown in FIG. 1A, a plurality of discharge nozzles 12 are actually provided in one header device 10. A plurality of pins 14 are provided as a whole of the header device 10 so as to individually correspond to the discharge nozzles 12.

  The ink chamber 11 is a space formed inside the header device 10. Inside the ink chamber 11, ink is supplied from an ink storage tank (not shown) through a supply channel 11 </ b> A by an ink supply mechanism (not shown). The ink inside the ink chamber 11 is pressurized to a constant pressure by the ink supply mechanism. In the present embodiment, the energy required for ejection is obtained from the ink from the ink chamber 11 through the valve 13 and through the ejection nozzle 12 by the pressure of the ink under pressure.

  The method of obtaining the ejection energy in the ink is not limited to the method of pressurizing the ink chamber 11 and opening and closing the valve 13 as in the present embodiment, but also includes a so-called thermal method in which the ink is heated to generate bubbles. Can take the way.

The discharge nozzle 12 corresponds to a flow path that penetrates a wall provided in the header device 10 or a plate (not shown) provided on the wall.
The outlet 122 of the discharge nozzle 12 is located at the tip of the discharge channel 100. In the present embodiment, the diameter D of the outlet 122 is the same as the cross-sectional diameter of the discharge channel 100.

The ejection nozzle 12 preferably has an introduction channel 101 having a larger cross-sectional area (channel cross-sectional area) than the ejection channel 100 in addition to the ejection channel 100 that ejects ink. The introduction channel 101 receives ink from the ink chamber 11 and introduces it into the ejection channel 100. By supplying ink from the ink chamber 11 to the discharge flow path 100 via the introduction flow path 101, it is possible to suppress ink pressure loss more than when ink is directly supplied from the ink chamber 11 to the discharge flow path 100. it can.
In order to further suppress the pressure loss of the ink, the channel cross-sectional area at the end of the introduction channel 101 is gradually reduced to the channel cross-sectional area of the discharge channel 100.

As shown in FIGS. 1A and 1B, both the introduction flow path 101 and the discharge flow path 100 of the present embodiment are cylindrical spaces having a circular cross section. The diameter of the introduction flow path 101 is larger than the diameter of the discharge flow path 100. The introduction channel 101 and the discharge channel 100 are arranged coaxially.
The peripheral edge portion of the inlet 121 of the discharge nozzle 12 that is the start end of the introduction channel 101 corresponds to a valve seat against which the tip end portion of the pin 14 is abutted. The valve 13 through which ink can pass from the ink chamber 11 to the discharge nozzle 12 includes a peripheral portion of an inlet 121 serving as a valve seat and a pin 14 serving as a valve body.

  The pin 14 is formed in a substantially cylindrical shape having a diameter larger than that of the inlet 121, and is driven along the axial direction by the actuator 15. The actuator 15 is configured to include a piezo element and the like, and drives the pin 14 to advance and retract with respect to the inlet 121 based on a command sent from the control unit.

As shown by a solid line in FIG. 1, the state in which the pin 14 is retracted with respect to the peripheral portion of the inlet 121 of the discharge nozzle 12 corresponds to a state in which the valve 13 is opened. At this time, the ink in the ink chamber 11 passes between the inner wall of the ink chamber 11 and the tip of the pin 14 and flows into the introduction channel 101 from the inlet 121. The outer peripheral portion on the tip end side of the pin 14 is gradually reduced in diameter toward the inlet 121 side in the axial direction so that a flow path through which ink smoothly flows is formed between the tip portion of the pin 14 and the inner wall of the ink chamber 11. It is formed to do.
As shown by a one-dot chain line in FIG. 1, when the pin 14 is abutted against the peripheral portion of the inlet 121 and the inlet 121 is closed, the valve 13 is closed.

When the pin 14 is retracted from the inlet 121 by the actuator 15, the valve 13 is opened for a predetermined opening time.
While the valve 13 is open, ink flows through the discharge channel 100 and is discharged from the outlet 122. Ink is ejected from the ejection channel 100 once every time the valve 13 is opened.
The opening time of the valve 13 is set to a time corresponding to the volume of ink ejected from the outlet 122 (described later). The opening time of the valve 13 can be set to 100 to 200 μs, for example.

  The volume of the ejection channel 100 is smaller than the volume of ink ejected from the outlet 122. For example, if the volume of the ejection channel 100 is about 100 to 300 pL, the volume of the ejected ink is 500 to 2500 pL, and the volume of the ejection channel 100 is sufficiently smaller than the volume of the ejection ink. Therefore, the entire amount of ink discharged from the outlet 122 and forming the droplet L (FIG. 2A) when the valve 13 is opened flows through the discharge channel 100. The ink flowing through the discharge channel 100 is discharged from the outlet 122 along the axial direction of the discharge channel 100 at a speed corresponding to the cross-sectional area of the discharge channel 100. The speed (ejection speed) of the ink ejected from the outlet 122 can be measured by, for example, image processing using data obtained by imaging a moving ink droplet with a camera. For the actual measurement of the speed of the ejected ink, a moving image shot by a camera capable of handling a high speed can be used.

  The cross-sectional shapes of the discharge channel 100 and the outlet 122 do not necessarily have to be circular, and can be determined to have an appropriate shape such as a rectangular shape.

The volume of ink ejected from the outlet 122 is preferably ^{0.5 × 10 3 pl~20 × 10 3} pl. More preferably ^{1 × 10 3 pl~5 × 10 3} pl.
The volume of the ejected ink is obtained, for example, by calculating the volume from the diameter of the droplet based on image data obtained by photographing the ejected and moving droplet with a camera, assuming that the droplet is a sphere. Can do.
The volume of the ejected ink corresponds to one opening of the valve 13. Due to the ink droplets landed on the surface to be painted, dots having a size corresponding to the volume of the droplets are formed on the surface to be painted. The size of the dot diameter may be uniform or different within the range of the volume of the ejected ink. The thickness of the coating film consisting of a set of dots is, for example, 25 to 75 μm.

  The volume of ink droplets in the present embodiment is remarkably large while the volume of ink droplets in a typical example of ink jet printing is several pl and remains at most about 10 pl. In general, inkjet printing is directed to high-definition print quality from fine dots formed by a very small amount of droplets. On the other hand, when the surface of a large area of a large member is to be painted as in this embodiment, it is also directed to efficiently advance the coating at a realistic work speed as well as the quality of the coating. For this reason, dots having a size corresponding to the volume of the liquid droplets are formed on the surface to be coated with the large volume liquid droplets ejected from the nozzle having a diameter larger than that of the nozzle for inkjet printing. The conventional spray gun coating for large structures such as aircraft can be replaced by the inkjet coating technique according to the present embodiment.

The ink ejected from the outlet 122 toward the front in the direction along the ejection flow path 100 passes through the state of a liquid column extending from the ink located at the outlet 122 as shown in (1) of FIG. As shown in (2), a droplet L is formed away from the outlet 122, and adheres (lands) on the surface to be coated, for example, several mm forward from the outlet 122.
The inner side of the rectangular frame line in FIG. 2A shows one dot 2 formed in a substantially circular shape on the surface to be painted due to the landing of the droplet L.
As shown in (1) and (2) of FIG. 2A, the shape of the front end portion of the ink ejected from the outlet 122 is spherical for stability in the external space of the ejection nozzle 12. The spherical front end part separates from the rear part and converges into one droplet L.

FIGS. 2B and 2C according to the comparative example show an example in which one or more satellites (small droplets) are separated from the droplet L (main droplet) and land after the droplet L has landed. ing. 2B and 2C, satellites (not shown) are located at positions shifted from the dots 2 formed by the main droplets in the moving direction of the header device 10 relative to the surface to be coated (the direction of the arrows). This shows an example in which small dots 2 ′ are formed by landing. The dot 2 ′ deviated from the dot 2 formed at a predetermined position on the surface to be coated reduces the coating quality.
In addition, although not shown in the drawing, a mist-like satellite composed of minute ink droplets is generated and floats, so that the header device 10 and the like may be soiled.

  When satellites are generated, for example, even if the ink ejected from the outlet 122 passes through the liquid column state shown in (1) of FIG. 2B and is separated from the outlet 122 as shown in (2), it is spherical. The tail T connected to the rear from the front end portion of the head remains long. In the example shown in FIG. 2C, the ejected ink does not leave the outlet 122, or it is slow to leave.

As an index representing various shapes and behaviors of the droplet L as shown in FIGS. 2A to 2C, the Weber number is generally used.
However, when an ink having a high viscosity as in the present embodiment is used, if an appropriate inertial force that does not generate satellites is applied to the ink, the ink cannot always be defined by the number of Webers.
In the present embodiment, the speed of the ink that flows through the discharge flow path 100 and is discharged from the outlet 122 is set to 6 m / s or more, and the Weber number is set to 14 to 120.
The ink ejection speed and the Weber number described above are suitable when using an ink having a viscosity of 80 to 350 mPa · s as described above.

The Weber number We is a dimensionless amount corresponding to the ratio between the inertial force and the surface tension of the liquid, and can be defined by the following equation.
We = (ρDV ² ) / σ
(Ρ: density of liquid, D: representative length of discharge port, V: representative speed of discharged liquid, σ: surface tension of liquid)
The density ρ and the surface tension σ are determined by the physical properties of the ink used.
In the present embodiment, D is the diameter of the outlet 122. Hereinafter, it is referred to as a nozzle diameter D. In addition, V is the speed of the ink that moves in the straight direction from the outlet 122 along the discharge flow path 100.
In addition, when the exit 122 is rectangular, D shall be the length of the short side of the exit 122.

  The Weber number (for example, 10 or less), which is said to be effective for reducing satellites with respect to ink for ink-jet printing on paper or the like, is determined according to a large droplet volume using high-viscosity ink as in this embodiment. When applied to ink jet coating in which the nozzle diameter is set, the energy required for ejection may be insufficient due to the viscous resistance of the ink, and the ink may remain at the outlet 122. In that case, although the diameter of the outlet 122, the pressure of the ink in the ink chamber 11, the opening time of the valve 13 and the like are determined so as to realize the Weber number which is said to be effective, the valve 13 is opened and the discharge channel 100 is opened. Even if the ink flows, the ink only swells outward from the outlet 122 or no behavior is observed in the ink near the outlet 122. That is, ink cannot be ejected.

The inventor of the present invention conducted a test to actually measure the speed (discharge speed) of the ink discharged from the outlet 122 using the prototype and model of the ink and the header device 10 of the present embodiment. In order for the ink to separate from the outlet 122 and move as the droplet L (FIG. 2A), that is, to be able to eject the ink, in terms of the ejection speed, 6 m / s or more is required.
In the above-described test, the presence or absence of satellites accompanying ink ejection was examined by observing the painted surface. As a result, if the Weber number We is 120 or less, no satellite is generated. Note that the presence or absence of satellites may be checked based on image processing based on data obtained by imaging the ejected droplets L with a camera.

The above items are arranged as specific examples in FIG. 3, and the Weber number We, the discharge speed V, and the nozzle diameter D will be described from the viewpoints of preventing the occurrence of satellites and whether ink can be discharged.
The vertical axis of the graph of FIG. 3 is the Weber number We, and the horizontal axis is the velocity V of the ink ejected from the outlet 122.

FIG. 3 plots the result of simulation and calculation when using an ink having a viscosity of 92 mPa · s, while changing the nozzle diameter D and plotting the lowest speed V at which ink can be ejected based on the test described above. The ejection enable / disable speed line L1 corresponding to 6 m / s, the satellite upper / lower limit line L2 corresponding to 120 which is the upper limit number of webers where no satellite is generated, and the lower limit weber capable of ejecting ink from the simulation or calculation result A dischargeable lower limit line L3 corresponding to the number 14 is shown.
The velocity V (less than 6 m / s) in the region on the left side of the ejection enable / disable velocity line L1 is a simulation or calculation value, and ink cannot be ejected from the outlet 122.

A plot corresponding to an ink pressure of 0.6 MPa in the ink chamber 11 is shown by a circle. In these plots, as shown in FIG. 3, the nozzle diameter D varies from 40 μm to 150 μm, changing by 5 μm between 40 and 60 μm and by 10 μm between 60 and 150 μm. Both the circular plot and the diamond plot draw a bowed curve.
A plot corresponding to an ink pressure of 0.4 MPa in the ink chamber 11 is indicated by diamonds (♦). In these plots, the nozzle diameter D varies from 50 μm to 150 μm, changing by 5 μm between 50 and 60 μm and changing by 10 μm between 60 and 150 μm.
In addition, the nozzle diameter in the case of general inkjet printing is about 10-30 micrometers, and is small compared with the nozzle diameter D of the plot shown in FIG.
From the circular plot and the rhombus plot, the ink velocity V changes when the pressure that applies the ejection energy to the ink changes, and the Weber number We for the velocity V also changes. However, even if the pressure or the speed V changes, the minimum dischargeable speed (6 m / s) indicated by the line L1, the upper limit (120) of the Weber number We that does not generate satellite, indicated by the line L2, and the line L3 The requirements for the lower limit (14) of the number of Webers that can eject ink are applied.
The plot data shown in FIG. 3 corresponds to a dischargeable velocity V in the range of 6 to 8.3 m / s.

This embodiment is based on the speed V and the Weber number We in the region R1 on the right side of the discharge possible / impossible speed line L1 and the hatched area R1 from the discharge possible lower limit line L3 to the satellite presence / absence upper limit line L2 in FIG. The main feature is that ink is ejected through the ejection channel 100.
Specifically, in terms of a circular plot, there are four plots having a nozzle diameter D of 100 μm, 55 μm, 50 μm, and 45 μm in the region R1. In the example shown in FIG. 3, a plot with a nozzle diameter D of 100 μm is located on the line L1 and on the line L2. This plot agrees with the actually measured minimum discharge speed (6 m / s). When the nozzle diameter D is reduced from the plot of the nozzle diameter D of 100 μm, even if discharge is possible, the region R2 returns to the region R1 again through the satellite-generated region R2 (55 μm, 50 μm, and 45 μm). ). However, when the nozzle diameter D is further reduced, the speed V is lower than the line L1, and the discharge is impossible in the region R3 (40 μm).
The rhombus plot shows the same tendency as above. In the rhombus plot, plots with the nozzle diameter D of 55 μm, 60 μm, 70 μm, and 100 μm exist in the region R1.
The plot data shown in FIG. 3 is a straight line L4 in the region R1, that is, the Weber number We is 14 to 120, the discharge speed V is 6 m / s or more, and We = 34.6V-180. It corresponds to the region that is on the upper side.

In the region R1, even when high viscosity ink is used, the ink can be discharged through the discharge flow path 100, and the generation of satellites can be prevented and the coating quality can be ensured.
The region R1 corresponds to the range of the volume of ink droplets described above ^{(0.5 × 10 3 pl~20 × 10} 3 pl).
In consideration of the change in the physical properties of the ink over time from the start of painting, it is preferable that the discharge speed V and the Weber number We at the start of painting are large in the appropriate region R1. The response to the change in physical properties includes, for example, a process of increasing the ink pressure in the ink chamber 11 in consideration of a decrease in the ejection speed accompanying an increase in ink viscosity.

  As in the embodiment described above, based on the speed V and the Weber number We defined in the region R1, the header device 10 discharges ink droplets having a large volume suitable for a large area toward the surface of the machine body. According to the repeated coating step, it is possible to ensure the coating quality while efficiently coating the surface of the airframe. By passing through this painting step, a member constituting the aircraft body can be manufactured.

In addition to the above, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.
According to the present invention, in particular, it can contribute to the practical application of inkjet coating of large-sized devices using large-viscosity droplets using high-viscosity ink, such as aircraft and other devices used outdoors. .

2 dots 10 header device 11 ink chamber (liquid chamber)
11A Supply flow path 12 Discharge nozzle 13 Valve 14 Pin 15 Actuator 100 Discharge flow path 101 Introduction flow path 121 Inlet 122 Exit D Nozzle diameter L Droplet L1 Discharge availability speed line L2 Satellite presence / absence upper limit line L3 Dischargeable lower limit lines R1 to R3 Region T tail

Claims (11)

An inkjet discharge method for discharging a liquid through a discharge channel,
When the viscosity of the liquid is 80 mPa · s or more and 350 mPa · s or less,
The speed of the liquid discharged through the discharge flow path is 6 m / s or more, and
Weber number is 14 or more and 120 or less,
An ink jet discharge method. The volume of the liquid discharged by the discharge flow path is
0.5 × 10 ³ pl or more and 20 × 10 ³ pl or less,
The inkjet discharge method according to claim 1. In a state where the liquid is pressurized to a predetermined pressure in the liquid chamber in which the liquid is placed, a valve that opens a valve through which the liquid can pass from the liquid chamber toward the discharge flow path Setting the opening time to a time corresponding to the volume of the liquid discharged by the discharge flow path;
The inkjet discharge method according to claim 1 or 2. Receiving the liquid from the liquid chamber in which the liquid is placed into the introduction flow path having a larger cross-sectional area than the discharge flow path and flowing into the discharge flow path;
The inkjet discharge method as described in any one of Claim 1 to 3. The discharge flow path has a circular cross section,
The Weber number is
When the density of the liquid is ρ, the diameter of the discharge port for discharging the liquid in the discharge flow path is D, the velocity of the liquid discharged from the discharge port is V, and the surface tension of the liquid is σ,
Represented by (ρDV ² ) / σ,
The inkjet discharge method as described in any one of Claim 1 to 4. A method for manufacturing a member, comprising:
Including the step of coating the member by the inkjet discharge method according to claim 1,
A member manufacturing method characterized by the above. The member constitutes an aircraft body,
The manufacturing method of the member of Claim 6. A liquid chamber in which a liquid having a viscosity of 80 mPa · s or more and 350 mPa · s or less is placed;
A discharge passage communicating with the liquid chamber and discharging the liquid;
The velocity of the liquid discharged through the discharge flow path is 6 m / s or more;
Weber number is 14 or more and 120 or less,
An inkjet apparatus characterized by that. The volume of the liquid discharged by the discharge flow path is
0.5 × 10 ³ pl or more and 20 × 10 ³ pl or less,
The inkjet discharge apparatus according to claim 8. The volume of the discharge channel is smaller than the volume of the liquid,
The inkjet discharge apparatus according to claim 9. An introduction flow path for receiving the liquid from the liquid chamber and flowing into the discharge flow path;
The discharge flow path has a circular cross section,
The introduction flow path has a circular cross section, the diameter of the cross section is larger than the discharge flow path, and is arranged coaxially with the discharge flow path,
The Weber number is
If the density of the liquid is ρ, the diameter of the discharge port that discharges the liquid in the discharge flow path is D, the velocity of the liquid discharged from the discharge port is V, and the surface tension of the liquid is σ ( represented by ρDV ² ) / σ,
The inkjet discharge apparatus as described in any one of Claims 8 to 10.

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