KR101103722B1 - Apparatus for jetting droplet - Google Patents

Abstract

The present invention relates to a droplet ejection apparatus for applying the electric field (electrostatic field) to the oil surface of the fluid injected through the nozzle to eject the fluid finely and efficiently in the form of droplets.

In the droplet ejection apparatus of the present invention, a droplet ejection apparatus for injecting droplets onto one surface of a printed matter, a chamber for receiving a certain amount of a fluid including liquid and particles supplied from the outside, and in communication with the chamber At least one nozzle for injecting droplets of fluid contained in the chamber onto one surface of the printed matter, and a first process provided by a patterning process for electrical contact with the fluid on an inner surface of at least one of the chamber and the nozzle A body portion provided with an electrode portion; A second electrode part disposed between the nozzle and the printed material, the second electrode part having a through hole through which droplets sprayed on one surface of the printed material through the nozzle are provided; A power supply unit applying a voltage between the first electrode unit and the second electrode unit; And a control unit controlling the power supply unit.

Droplets, sprays, electrodes, prints, nozzles, chambers

Description

Droplet Injector {APPARATUS FOR JETTING DROPLET}

The present invention relates to a droplet ejection apparatus, and more particularly, to apply the electric field (electrostatic field) to the oil surface of the fluid injected through the nozzle to eject the fluid finely and efficiently in the form of droplets (Droplet). A droplet ejection apparatus.

In general, a droplet ejection apparatus that ejects (discharges) a fluid in the form of droplets using an electrostatic field has been mainly applied to inkjet printers. Recently, display processing apparatuses, printed circuit board processing apparatuses, and DNA chip manufacturing processes Applications are being developed for applications in the same high-end, high value-added fields.

In the above ink jet printer, the ink ejection value for ejecting ink in the form of droplets is largely divided into a thermal drive method and an electrostatic force method.

First, as shown in FIGS. 1 and 2, the ink ejection device of the thermal drive method is formed by the manifold 22 provided in the substrate 10 and the partition wall 14 formed on the substrate 10. An ink channel 24 and an ink chamber 26 which are constrained constrained, a heater 12 provided in the ink chamber 26, and a nozzle provided in the nozzle plate 18 to eject ink droplets 29 ′. (16), the ink ejection device of the thermal drive method is to eject the droplet 29 'through the following operation.

When a voltage is supplied to the heater 12, heat is generated, and the ink 29 filled in the ink chamber 26 is heated by this heat to generate bubbles 28.

Next, the generated bubble 28 continues to expand, so that pressure is applied to the ink 29 filled in the ink chamber 26, and the ink droplet 29 ′ is discharged through the nozzle 16. 16) It is sprayed to the outside.

Thereafter, the ink chamber 26 is refilled with the ink 29 while the ink 29 is sucked into the ink chamber 26 through the ink channel 24 from the manifold 22.

However, the above-described conventional thermally driven ink jetting device may cause a chemical change of the ink 29 due to the heat of the heater 12 for forming a bubble, so that the quality of the ink 29 There is a disadvantage that problems such as degradation can occur.

In addition, the droplet 29 'of the ink ejected through the nozzle 16 may cause a rapid volume change due to the heat of the heater 12 while moving toward an object such as paper. There is also a problem that the print quality is degraded.

In addition, there is a problem in that the thermal injection type ink jetting device has a limitation in fine control of the droplet 29 'injected through the nozzle 16, for example, the size and shape of the droplet.

In addition, due to the above problems, there is also a problem that it is difficult to implement a high-density droplet ejection apparatus.

3 and 4 illustrate another method of the droplet ejection apparatus, that is, an electrostatic force droplet ejection apparatus using an electric field.

In more detail, the electrostatic force type droplet ejection apparatus, as shown in FIGS. 3 and 4, is provided with an opposing electrode 33 positioned to face the base electrode 32. Ink 31 is injected between the two electrodes 32 and 33, and a DC power supply 34 is connected to the two electrodes 32 and 33.

When a voltage is applied to the electrodes 32 and 33 by the DC power supply 34, an electrostatic field is formed between the two electrodes 32 and 33.

Accordingly, Coulomb's Force acting in the direction of the counter electrode 33 acts on the ink 31.

On the other hand, since the repulsive force with respect to the coulomb force also acts on the ink 31 due to its inherent surface tension and viscosity, the ink 31 is not easily ejected toward the counter electrode 33.

Therefore, in order to separate the droplet from the surface of the ink 31 and to eject it, a high voltage of 1 kV or more must be applied between the electrodes 32 and 33.

However, when a high voltage is applied between the electrodes 32 and 33, the ejection of the droplets occurs very irregularly, thereby locally heating a predetermined portion of the ink 31.

That is, the temperature T1 of the ink 31 'positioned in the region of S1 rises higher than the temperature T0 of the ink 31 positioned in the other region, so that the ink 31' of the region S1 is As it expands, the electrostatic field is concentrated in this region, which attracts a large number of charges.

Accordingly, the repulsive force acting between the charges and the coulomb force due to the electrostatic field act on the ink 31 'of the S1 region, and as shown in FIG. 4, from the ink 31' of the S1 region. As the droplets are separated, they move toward the counter electrode 33.

However, the electrostatic force type droplet ejection apparatus as described above has a problem in that a very high voltage of 1 kV or more must be applied to the electrodes 32 and 33, and the external counter electrode 33 must be provided in a direction facing the nozzle.

An object of the present invention for solving the problems according to the prior art, by applying a controllable electrostatic field to the oil surface of the fluid injected through the nozzle, it is possible to inject the fluid in the form of a drop (Droplet) without a thermal change The present invention provides a droplet spraying device capable of finely controlling the sprayed droplets through the first electrode portion, the second electrode portion, and the third electrode portion.

In the droplet ejection apparatus of the present invention for solving the above technical problem, a droplet ejection apparatus for injecting droplets on one surface of the printed matter, a chamber for accommodating a certain amount of fluid containing liquid and particles supplied from the outside; Patterning treatment for electrical contact with the fluid on at least one nozzle and at least one of the chamber and at least one of the chamber and the nozzle for injecting droplets of fluid communicated from the chamber and contained in the chamber to one surface of the printed matter. A body portion provided with a first electrode portion provided by; A second electrode part disposed between the nozzle and the printed material, the second electrode part having a through hole through which droplets sprayed on one surface of the printed material through the nozzle are provided; A power supply unit applying a voltage between the first electrode unit and the second electrode unit; And a control unit controlling the power supply unit.

Here, the body portion, the upper plate and the lower plate is configured to be in contact with each other, the upper surface of the lower plate is formed so as to extend from the rectangular groove to form the chamber to the front side of the lower plate from the rectangular groove to the nozzle Longitudinal grooves to achieve, and a supply hole formed to penetrate downward from the rectangular grooves so that the fluid can be supplied from the outside.

Here, the third electrode unit is spaced apart from the other surface of the printed matter; may further include.

The power supply unit may apply a voltage between the first electrode portion and the third electrode portion.

The second electrode part may be formed by alternately stacking an electrode plate and an insulating plate.

In this case, voltages applied between the electrode plates of the first electrode part and the second electrode part may be individually controlled by the controller.

The voltage applied between the first electrode portion and the second electrode portion may be any one of a DC pulse voltage, an AC voltage, or a voltage for applying an AC voltage while applying a DC voltage.

Here, the end of the nozzle may be formed to protrude outward.

Here, a hydrophobic film may be applied or coated on the end surface of the nozzle.

Here, the body portion may be made of a polymer material.

Here, the body portion may be formed by communicating a plurality of nozzles from one chamber.

On the other hand, to form an electrostatic field together with the first electrode portion and the first electrode portion provided on one side of the printed material for electrical contact with the fluid and to spray the droplets on one surface of the printed material on one side or the other side In the droplet ejection apparatus provided with the second electrode portion, a voltage applied between the first electrode portion and the second electrode portion is a DC pulse voltage, an AC voltage, or a voltage for applying an AC voltage while applying a DC voltage. It can be either.

The present invention as described above, by applying a controllable electrostatic field to the surface of the fluid injected through the nozzle, it is possible to inject the fluid in the form of a drop (Droplet) without thermal changes, the first electrode portion, Advantageously, the sprayed droplets can be finely controlled through the second electrode portion and the third electrode portion.

In addition, in arranging a plurality of droplet ejection devices having a configuration according to an embodiment of the present invention at predetermined intervals, there is an advantage that a highly integrated arrangement is possible without being affected by various thermal problems as in the prior art. .

The invention will become more apparent through the preferred embodiments described below with reference to the accompanying drawings. Hereinafter will be described in detail to enable those skilled in the art to easily understand and reproduce through embodiments of the present invention.

As shown in FIG. 6, the droplet ejection device according to the present embodiment is largely provided with a body part 100, a second electrode part 140, and a third electrode part 150 provided with the first electrode part 130. ), The power supply unit 200 and the control unit 300 is configured.

The main body part includes a chamber 110, a nozzle 120, and a first electrode part 130, and the chamber 110 is a part for accommodating a certain amount of a fluid including liquid and particles supplied from the outside, The nozzle 120 communicates with the chamber 110 to inject droplets of the fluid contained in the chamber 110 onto one surface of the printed matter A, and the first electrode part 130 is the chamber 110 and the nozzle. It is a part provided by the patterning process for the electrical contact with the fluid in the inner surface of at least one of 120.

The second electrode unit 140 is installed between the nozzle 120 and the printed matter A, and the through hole 140h through which the liquid droplets sprayed onto one surface of the printed matter A passes through the nozzle 120. The power supply unit 200 is a portion for applying a voltage between the first electrode unit 130 and the second electrode unit 140, and the control unit 300 controls the power unit 200. The third electrode part 150 is a part spaced apart from the other surface of the printed matter A.

First, the body portion 100 will be described.

5 and 6, the body portion 100 is in communication with the chamber 110, the chamber 110 for receiving a certain amount of the fluid containing the liquid and particles supplied from the outside, the chamber 110 The first electrode portion 130 provided by the patterning process for electrical contact with the fluid on the nozzle 120 and the inner surface of the chamber 110 for injecting the droplet of the fluid contained in the printed matter (A) on one surface It is configured to include.

For example, the body portion 100, as shown in Figure 5, the lower surface of the upper plate (100a) and the upper surface of the lower plate (100b) can be configured in contact with, and the lower plate (100b) On the upper surface, a rectangular groove for forming the chamber 110 is formed in contact with the lower surface of the upper plate 100a, and at the same time, a longitudinal groove for forming the nozzle 120 is continued from the rectangular groove to lower plate 100b. And a supply hole 110h penetrating into the lower surface of the lower plate 100b from the rectangular groove so as to receive the fluid from the outside.

6 and 9, when the lower surface of the upper plate 100a and the upper surface of the lower plate 100b abut and are attached to each other so that the nozzle 120 is formed, the end of the nozzle 120 has an outer side. It is configured to be formed to protrude into. The end of the nozzle 120 is formed to protrude outward in order to maintain a larger contact angle when the liquid level of the fluid is formed to promote stability of the liquid level.

FIG. 11 shows the difference between the liquid level formed in the device (a) which simply drills the nozzle on the surface and the device (b) with the protruding nozzle and shows the distribution of the electric field according to the shape of the liquid surface. The smaller the surface radius (R) of the liquid level means that the liquid surface is closer to the hemispherical shape. The smaller the surface radius (R) of the liquid surface, the higher the intensity of the electric field and it can be seen that the concentration in the center. Therefore, it can be said that the nozzle of the protruding structure provides a lot of benefits in terms of jetting.

In addition, a hydrophobic film may be applied or coated on the end surface of the nozzle 120, and for example, a hydrophobic surface may be formed through an oxygen plasma process or an argon and oxygen ion beam process. This is because the end surface of the nozzle 120 is made of a hydrophobic membrane, so that the formation of the initial meniscus of the fluid during the droplet injection through the nozzle 120 effectively occurs, and even if repeated spraying stability and efficiency of the spray phenomenon To increase.

On the other hand, as shown in Figure 8 and 9, the body portion 100 may be formed in communication with a plurality of nozzles 120 from one chamber 110, in detail, the lower plate (100b) One rectangular groove for forming the chamber 110 is formed at the same time, and three longitudinal grooves for forming the three nozzles 120 are formed from the rectangular grooves, respectively, to the front side of the lower plate 100b. In order to receive the fluid from the outside, the supply hole 100h penetrating from the rectangular groove to the lower surface of the lower plate 100b is formed.

Here, as shown in FIG. 5, although the first electrode 130 is provided by the patterning process on the inner surface of the chamber 110 for electrical contact with the fluid, as shown in FIG. 8, Of course, the first electrode 130 may be provided on the inner surface of each nozzle 120 by a patterning process for electrical contact with the fluid. The first electrode 130 may be provided on the lower surface of the upper plate 100a.

On the other hand, the body portion 100 is preferably made of a polymer material, which is, when a plurality of droplet ejection apparatus is arranged next to each other or a plurality of nozzles 120 are formed in one chamber 110 as shown in FIG. In order to prevent electrical interference between the droplet ejection apparatuses or the plurality of nozzles 120 arranged adjacent to each other, the body portion 100 is formed of a polymer material that is not electrically conductive.

On the other hand, the body portion 100 may be manufactured using a PDMS molding (polydimethylsiloxane moldind) method.

Next, the second electrode unit 140 and the third electrode unit 150 will be described.

As shown in FIG. 5 and FIG. 6, the second electrode part 140 is installed between the nozzle 120 of the body part 100 and the print A, and the print A through the nozzle 120. Through holes 140h through which the droplets are injected to one surface of the through are provided.

A voltage is applied between the second electrode unit 140 and the first electrode unit 130 provided in the body unit 100 as described above by the power supply unit 200, which will be described later, to the chamber 110. The supplied fluid may be injected into the nozzle 120 to penetrate the through hole 140h and to be printed on the printed matter A. FIG. Specifically, when a voltage is applied between the first electrode 130 and the second electrode 140, an electrostatic field is formed between the first electrode 130 and the second electrode 140, Accordingly, Coulomb's Force acting in the direction of the second electrode portion 140, which is the opposite electrode, is applied to the fluid, and the droplet is sprayed onto the printed matter A through the nozzle 120.

In this case, as shown in FIGS. 7 and 10, the second electrode unit 140 is formed by alternately stacking the electrode plate 142 and the insulating plate 144, and the first electrode unit 130 and the first electrode unit 130 are formed. Voltages applied between the electrode plates 142 of the two-electrode unit 140 may be individually controlled by the controller 300, which will be described with reference to the power supply unit 200 and the control unit 300. Be sure to do it in detail.

8 and 9, in the case of the body part 100 formed by communicating a plurality of nozzles 120 from one chamber 110, each of the nozzles 120 corresponds to a position corresponding to each nozzle 120. The second electrode unit 140 is provided so that the voltage applied between the first electrode unit 130 and each of the second electrode units 140 can be individually controlled.

As shown in FIGS. 5 and 6, 8, and 9, the third electrode unit 150 is spaced apart from the other surface of the printed matter A, and the third electrode unit 150 and the first electrode unit are disposed. Voltage is applied between the 130, and as the voltage is applied between the third electrode 150 and the first electrode 130, the coulomb's force acts even more. The straightness of the sprayed droplets through 120 may be enhanced.

Next, the power supply unit 200 and the control unit 300 will be described.

As shown in FIG. 6 and FIG. 9, the power supply unit 200 is disposed between the first electrode unit 130 and the second electrode unit 140 and between the first electrode unit 130 and the third electrode unit 150. A voltage is applied between the controller 300 and the controller 300 to control the power supply unit 200.

On the other hand, as described above, the controller 300 individually controls the voltage applied between the first electrode 130 and each electrode plate 142, the first electrode 130 and each second The voltages applied between the electrode units 140 may be individually controlled, and the voltages applied to the first electrode unit 130 and the electrode plates 142 may be individually controlled.

For example, the voltage between the first electrode unit 130 and the electrode plate 142 close to the nozzle 120 and the voltage between the first electrode unit 130 and the electrode plate 142 far from the nozzle 120 are different from each other. If applied, the acceleration of the droplet can be varied to have a + or-value. As the acceleration of the droplets changes as described above, the print quality printed on the printed matter A also changes. In other words, the pattern may vary depending on the amount of impact when the droplets collide with the printed matter, and patterning in applications such as display, RFID, solar cell, etc., rather than simply printing a document, may be affected by the uniformity of the line and waveness. There may be a difference in performance, so control is required. If the speed is controlled after the formation of droplets, more optimal collision and printing can be expected.

The voltage applied between the first electrode part 130 and the second electrode part 140 may be one of a DC pulse voltage, an AC voltage, or a voltage for applying an AC voltage while applying a DC voltage. Can be.

The charge is charged at the interface of the fluid by the continuous signal of the direct current voltage, the charge is generated in the tangential direction of the interface, the concentration of the electrostatic force occurs near the center of the liquid droplets can be formed and discharged. However, since the change of interface and jetting mode are different according to the applied voltage, the electrical conductivity of the fluid, the surface tension coefficient, and the viscosity, the droplets can be generated and discharged only under very limited conditions where a single droplet is formed in the case of continuous signals. Can be.

In order to overcome this problem, applying a pulse of DC voltage acts on the interface of the droplets for a limited time, so that the desired number of droplets can be generated and discharged at a desired time, and continuous jet or cone-jet can be used. Also in the case of the droplets can be formed by cutting the continuous jet. However, even in this case, droplets can be effectively generated by applying the optimum conditions according to the applied voltage and the physical characteristics of the fluid. That is, in order to generate a desired number of droplets at a desired time point, a pulse of an optimal voltage and frequency should be applied according to the characteristics of the fluid.

On the other hand, in the electrospray research, it is reported that the change of the fluid interface is possible even by the AC voltage. Therefore, the present embodiment proposes the generation and discharge of droplets using the AC voltage.

In addition, in order to enhance the efficiency and effect of the above-described droplet generation and discharging, if an AC voltage of a specific frequency is applied while applying a DC voltage in a range in which the fluid does not spray or generate droplets, It can be produced and discharged and can provide more stable optimum conditions.

Although the present invention has been described with reference to the preferred embodiments thereof with reference to the accompanying drawings, it will be apparent to those skilled in the art that many other obvious modifications can be made therein without departing from the scope of the invention. Accordingly, the scope of the present invention should be interpreted by the appended claims to cover many such variations.

1 and 2 is an exemplary view showing a conventional thermal drive type droplet injection device.

3 and 4 is an exemplary view showing a conventional electrostatic force droplet ejection apparatus.

Figure 5 is a perspective view showing a body portion of a droplet ejection apparatus having one nozzle according to an embodiment of the present invention.

6 is an exemplary view showing a droplet injection value according to an embodiment of the present invention.

7 is a cross-sectional view taken along line AA ′ of FIG. 6.

8 is a perspective view showing a body portion of a droplet ejection apparatus having a plurality of nozzles according to an embodiment of the present invention.

9 is an exemplary view showing a droplet injection value according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view taken along line BB ′ of FIG. 9.

11 is a view for explaining the effect of the projecting nozzle of the droplet ejection apparatus according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: body portion 100a: upper plate

100b: lower plate 110: chamber

120: nozzle 130: first electrode portion

140: second electrode portion 142: electrode plate

144: insulating plate 150: third electrode portion

200: power supply unit 300: control unit

A: Print

Claims (8)

In the droplet ejection apparatus for injecting droplets on one surface of the printed matter, A chamber for receiving a certain amount of fluid containing liquid and particles supplied from the outside, and a droplet of fluid communicated from the chamber and received in the chamber onto a surface of one side of the print, wherein at least an end surface is coated or coated with a hydrophobic film; A body part including one nozzle and a first electrode part provided on an inner surface of at least one of the chamber and the nozzle by a patterning process for electrical contact with the fluid; A second electrode part disposed between the nozzle and the printed material, the second electrode part having a through hole through which droplets sprayed on one surface of the printed material through the nozzle are provided; A power supply unit applying an AC voltage while applying a DC voltage between the first electrode unit and the second electrode unit; And And a control unit for controlling the power supply unit. The body portion, It is made of a polymer material, the upper plate and the lower plate is configured to abut each other, the upper surface of the lower plate is formed to extend from the rectangular groove to form the chamber, from the rectangular groove to the front side of the lower plate to the nozzle And a feeding hole formed so as to penetrate downward from the rectangular groove so as to receive the fluid from the outside. delete The method of claim 1, And a third electrode unit spaced apart from the other surface of the printed matter. The method of claim 3, And the power supply unit applies a voltage between the first electrode portion and the third electrode portion. The method of claim 1, And the second electrode part is formed by alternately stacking an electrode plate and an insulating plate. The method of claim 5, And a voltage applied between each of the electrode plates of the first electrode part and the second electrode part is individually controlled by the controller. The method of claim 1, Droplet injection device characterized in that the end of the nozzle is formed to protrude outward. The method of claim 1, The body portion droplet ejection apparatus, characterized in that formed by communicating a plurality of nozzles from one chamber.

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