KR101098341B1 - Sided electrode for electrifying fluid in ink jet head assembly - Google Patents

Abstract

The present invention relates to an ink jet head assembly in which an electrode is inserted from a side, and the electrode inserted from the side makes it possible to minimize the contact area between the fluid and the electrode, thereby facilitating the flow of the fluid. Of course, it can thereby lower the voltage required for injection, and as a result, there is an effect that can increase the service life of the head assembly.

Electrodes, Side Insertion, ESD, Piezo Actuators

Description

Sided electrode for electrifying fluid in ink jet head assembly

The present invention relates to an ink jet head assembly in which an electrode is inserted from a side, and the electrode inserted from the side makes it possible to minimize the contact area between the fluid and the electrode, thereby facilitating the flow of the fluid. Of course, it can thereby lower the voltage required for injection, and as a result, there is an effect that can increase the service life of the head assembly.

In general, the electrostatic deposition (ESD) method refers to a printing technique that ejects ink droplets using an electric field.

The method was developed to control the electrostatic field to deposit proteins or charged nanoparticles on a specific area of the conductive substrate. The deposition amount can be controlled by the size of the droplet, the concentration of the sample, the injection time, and various patterns. It can be deposited at the same time, so that it is possible to spray a large area at high speed.

The principle of electrostatic induction deposition is briefly described through the conceptual diagram of FIG. 1.

As shown in the figure, a nozzle 21 having a small diameter for discharging ink is located above, and a ground 22 is located directly below. At this time,

When the positive or negative voltage is applied to the nozzle 21 and the negative or negative voltage is applied to the ground 22, the conductive ink passing through the nozzle 21 is applied. It is charged to the same pole as the nozzle 21, so that the conductive ink is printed on the printed object (not shown) on the ground 22 by the attraction force (magnetic force) with the ground 22 of the opposite electrode.

However, such an ESD printing technique has a problem in that a large amount of energy is required for miniaturization of ink droplets.

In order to solve this problem, a printing method using a piezoelectric actuator is proposed.

Piezoelectric actuator method is divided into a method using a piezoelectric piezoelectric (Piezo Electric) or ceramic piezoelectric (ceramic Electric).

The piezoelectric piezoelectric is a method of spraying ink at a mechanical pressure by using a piezo actuator.

When the printer sends an electric signal to the piezoelectric element, the piezoelectric element vibrates and ink is pushed out of the nozzle hole by the pressure of the vibration. The escaped part is filled by the phenomenon of Moses and the law of inertia.

In addition, the ceramic piezo is operated by reciprocating the stretched state and the reduced state of each crystal by applying or removing an electric field in the same direction after the polarization of the ceramic.

The ink jet head assembly 10 by the piezoelectric actuator method will be described with reference to FIG. 2.

2 is a conceptual diagram illustrating a cross section of the ink jet head assembly 10.

As shown, an ink inlet 11 is formed at one side of the ink jet head assembly 10.

After the ink flows from the ink reservoir (not shown) to the ink inlet 11, ink is introduced into the ink jet head assembly 10 through the ink inlet 11.

The introduced ink is introduced into the ink chamber 13 through the channel 12.

Ink injected into the ink chamber 13 is injected through the nozzle 15, and at this time, the piezoelectric actuator 14 as described above is deformed to eject the ink.

The piezoelectric actuator method is advantageous in that the ejection of ink can be precisely controlled by the current control.

By adjusting the time for controlling the current of the piezoelectric element when the ink bubble swells, it is possible to control the size of the ink ink to be pushed out.

As a result, the nozzle is large and ink droplets can be made small, and the multi-size dot function of making ink droplets of various sizes with one nozzle can be realized. This multi-size dot function can be used to adjust the size of the dot according to the printed body, which helps in speed improvement.

It is also possible to use such a piezoelectric actuator method and the above-described ESD method, which will be described in more detail with reference to FIG. 3.

In FIG. 3, the piezoelectric actuator type ink jet assembly and the basic structure are the same, and only the ink chamber 33 and the electrode 34 are enlarged.

As shown, ink flows into the ink chamber 33.

The introduced ink is conducted by the electrode 34 and sprayed through the nozzle 32.

At this time, the nozzle 32 is inserted from the upper side on the drawing of the ink chamber 33 as shown, is inserted into the lower side of the ink chamber 33.

However, in the conventional ink jet head assembly 30, the electrode 34 for conducting the ink has a large contact area with the ink, thus preventing the flow of the ink.

Due to this phenomenon, clogging occurs in the nozzle 32.

In addition, as described above, the flow of the ink is disturbed, and in order to secure a predetermined injection amount, the voltage to be household appliances must be increased, thereby reducing the service life of the head assembly.

The present invention is to solve the above-described problems by inserting an electrode on the side of the ink chamber to minimize the contact area between the electrode and the ink and thereby lower the voltage required, resulting in a service life of the ink jet head assembly It is an object to provide an ink jet head assembly that can be increased.

The present invention for achieving the above object is an ink jet head assembly for spraying the ink temporarily stored in the ink chamber by electrostatic induction,

The ink jet head assembly is characterized in that the electrode is inserted into one side of the ink chamber and enters into the ink chamber, and the electrode including the ground disposed on one side of the ink chamber is side-inserted.

In addition, an ink jet head assembly for ejecting ink temporarily stored in the ink chamber by electrostatic induction, comprising: an electrode inserted at one side of the ink chamber and entering the ink chamber, and provided at one side of the ink chamber; Another feature of the ink jet head assembly is that a piezoelectric actuator for pressurizing the ink stored in the ink chamber and an electrode including a ground disposed on one side of the ink chamber are side-inserted.

In addition, an ink jet head assembly for spraying ink temporarily stored in the ink chamber by electrostatic induction, the head housing having a box shape and a plurality of ink chambers for temporarily storing the ink, An electrode inserted from one side to enter the ink chamber, a piezoelectric actuator mounted on one side of the ink chamber to pressurize the ink stored in the ink chamber, and a ground disposed on one side of the ink chamber; Another feature of the ink jet head assembly is that the electrodes are laterally inserted.

In this case, the electrode may have a cylindrical shape, but the tip portion entered into the ink chamber may have a pointed shape.

In addition, the electrode may include a pair of electrodes, each of which may be inserted into both sides of the ink chamber to enter the ink chamber.

In addition, the electrodes may be disposed to be inclined downward toward the ink chamber toward the center of the ink chamber, and may be disposed to have an angle of 50 to 60 degrees with respect to the radial plane of the ink chamber.

The front end portions of the electrode in the ink chamber may be spaced apart from each other by 1 mm to 1.5 mm in the height direction of the ink chamber.

The apparatus may further include a nozzle disposed at a lower end of the ink chamber, wherein the nozzle is disposed at a lower end of the ink chamber and has the same center as a depth center of the ink chamber, the same diameter in the depth direction of the ink chamber. The capillary having the shape to be maintained and the orifice having the shape that is disposed below the capillary and whose diameter decreases toward the lower side may be included.

Further, the piezoelectric actuator may include a plate-shaped vibration plate installed on the upper side of the ink chamber, and a piezoelectric element installed on the vibration plate.

The apparatus may further include an insulating plate having a plate shape disposed between the ink chamber upper side and the vibrating plate, wherein the insulating plate may be formed with an ink insertion hole communicating with the ink chamber side and an electrode insertion hole into which the electrode is inserted.

The apparatus may further include a spacer assembly disposed between the insulating plate and the vibrating plate to form a space in which ink may flow by securing a gap between the insulating plate and the vibrating plate.

In addition, the spacer assembly includes a plate-shaped base plate, a plurality of upper spacers disposed on the base plate and arranged to be spaced apart from each other, and ink penetrating through the upper spacers through the base plate between the upper spacers. It may include an ink input hole formed to flow to the ink input hole side of the insulating plate.

As described above, the contact area between the electrode and the ink is minimized, thereby facilitating the flow of the ink.

In addition, the ink can be easily flowed to prevent the occurrence of clogging phenomenon and to lower the required voltage.

This also has the effect of increasing the service life of the ink jet head assembly.

Hereinafter, with reference to the accompanying drawings and embodiments will be described in detail with respect to the present invention.

4 is a conceptual diagram illustrating the concept of the present invention.

5 is an exploded perspective view showing one embodiment of the ink jet head assembly of the present invention.

As described above, the present invention is described through the following embodiments by inserting electrodes on both sides of the ink chamber to minimize the contact area between the ink and the electrodes.

Example 1

In this embodiment, the case of ejecting ink by the ESD method will be described.

The ink jet head assembly 30 of the present invention is an ink jet head assembly 30 in which the ink temporarily stored in the ink chamber 33 is sprayed by electrostatic induction, as shown in FIG. It includes an electrode (E) inserted from one side of the to enter the ink chamber 33, and the ground (G) is provided on one side of the ink chamber (33).

Conventionally, the electrode was inserted into the upper end of the ink chamber (see Fig. 3). However, in the conventional case, there is a problem that the flow of ink is hindered because the contact area between the electrode and the ink is wide.

However, according to the present invention, since the electrode E is inserted from one side of the ink chamber 33, the area in contact with the ink can be minimized.

On the other hand, the electrode (E) has a cylindrical shape, but the front end portion entering the ink chamber preferably has a pointed shape.

This is because the electric field is concentrated in the pointed portion to help the creation of the meniscus.

As shown in FIG. 4, the electrode E is formed at the end of the cylindrical bar E1 and the bar E1 in the direction in which the electrode E is inserted into the ink chamber 33. It may include.

This aims at minimizing the contact area with the ink as described above and making it possible to easily create a meniscus. As long as this object is achieved, all of the electrodes E may have different shapes. Naturally, it belongs to the scope of the present invention.

This is the same in other embodiments described below, and overlapping description is omitted.

On the other hand, the electrode (E) may be provided with a pair of electrodes, respectively inserted from both sides of the ink chamber 33 may enter the ink chamber 33, respectively.

This is slightly disadvantageous in terms of minimizing the contact area with the ink, but instead it is advantageous to charge the ink.

As shown in Table 1 below, the voltage for generating the meniscus is 3KV, which is slightly higher than the 2.6KV of the conventional electrode, but the voltage for ink ejection is 3.8KV, which is higher than the 500KV of the conventional electrode. Significantly lower

Therefore, only one electrode E is used, and thus the effects as described above can be expected.

However, as shown in [Table 1], two electrodes E are used, but it is more preferable to insert them from both sides of the ink chamber 33 as described above.

That is, when two electrodes are used, the meniscus generation voltage is 1.3KV, which is significantly lower than the conventional 2.6KV, and lower than the case of using one electrode as described above.

In addition, the voltage for jetting is 2.75 KV when using two electrodes, which is significantly lower than the conventional 500 KV.

As can be seen from such experimental data, it is preferable to use two electrodes of the present invention.

The same applies to the embodiments described later, and duplicate descriptions are omitted.

No.


Electrode type
Droplet analysis
Meniscus
Generate required voltage Jetting Required Voltage One 1 electrode with circular cross section
(Inserted from the side of the ink chamber) 3 KV (DC)
3.8 KV (DC)
2 2 electrodes with circular cross section
(Inserted on both sides of the ink chamber) 1.3 KV (DC) 2.75KV (DC)
3 Conventional electrodes
(Inserted from the top side of the ink chamber) 2.6 KV (DC) 500KV (DC)

However, the voltage needed to generate the meniscus was tested under a distance of 250um.

In addition, the voltage required for jetting the ink is a distance of 200um to 250um, the flow rate was tested at 100ul / hr conditions.

Meanwhile, as shown in FIG. 4, the electrodes E are disposed to be inclined downward toward the ink chamber toward the center of the ink chamber, and have an angle of 50 degrees to 60 degrees with respect to the radial plane of the ink chamber. It is preferred to be arranged obliquely.

In addition, the tip portion E2 in the ink chamber inner direction of the electrode E may be spaced apart from each other at intervals of 1 mm to 1.5 mm in the height direction of the ink chamber.

The insertion angle or the separation distance of the electrode (E) is the same in the embodiments described later, and overlapping description is omitted.

On the other hand, it is also possible to further include a nozzle (N) disposed in the lower end of the ink chamber 33 described above.

The nozzle (N) is disposed at the lower end of the ink chamber, and has the same center as the depth direction center of the ink chamber, the capillary tube (N1) having the same diameter in the depth direction of the ink chamber and the capillary tube It may include an orifice (N2) having a shape that is disposed below (N1) as the diameter decreases toward the lower side.

Such nozzles N can facilitate ink injection.

On the other hand, the nozzle (N) is the same in the embodiments to be described later, overlapping description is omitted.

Example 2

In this embodiment, the above-described ESD method and the method using the piezoelectric actuator are used together.

That is, the point is the same as the ink jet head assembly 30 which injects the ink temporarily stored in the ink chamber 33 by electrostatic induction.

In this case, the electrode E may be inserted into one side of the ink chamber 33 to enter the ink chamber 33, and the ground G may be disposed on one side of the ink chamber 33. Although the viscosity is the same, it is different in that it includes a piezoelectric actuator A which is provided on one side of the ink chamber 33 to pressurize the ink stored in the ink chamber 33.

That is, as shown in FIG. 4, the piezoelectric actuator A is disposed on the upper side of the ink chamber 33 to help eject the ink by pressurizing the piezoelectric actuator A. FIG.

The piezoelectric actuator A will be described in more detail in Example 3 described later.

Other details are the same as in the first embodiment, so detailed description thereof will be omitted.

Example 3

In the present embodiment, the point is the same for the ink jet head assembly 100 for ejecting the ink temporarily stored in the ink chamber 112 by electrostatic induction.

However, as shown in FIG. 5, a head housing 110 having a box shape and having a plurality of ink chambers 112 temporarily storing the ink therein is inserted into one side of the ink chamber 112, and the ink chamber (112) an electrode (E) entering into the inside, a piezoelectric actuator (A) which is installed on one side of the ink chamber 112 to pressurize the ink stored in the ink chamber 112, and the ink chamber 112 The point which includes the ground G provided in one side on the other side is different.

That is, in this embodiment, a plurality of ink chambers 112 are formed in the head housing 110, and the electrode E described above is installed in the ink chamber 112.

In this case, the piezoelectric actuator A may include a plate-shaped vibration plate A2 installed on the upper side of the ink chamber, and a piezoelectric element A1 installed on the vibration plate A2.

As the piezoelectric element A1 is deformed by receiving power, the vibrating plate A2 is vibrated, and the ink is pressed to the nozzle side by the vibration, thereby discharging the ink.

At this time, it is also possible to further include a plate-shaped insulating plate 130 is provided between the ink chamber upper side and the vibration plate (A2).

The insulating plate 130 may have an ink insertion hole 131a communicating with the ink chamber 112 side and an electrode insertion hole 132 into which the electrode E is inserted.

Ink is introduced into the ink chamber 112 through the ink input hole 131a.

5 illustrates electrode insertion holes 132a and 132b formed at both sides of the ink input hole 131a, respectively.

This is due to the object of using two electrodes E of the present invention described above.

Therefore, when one electrode E is used, one electrode insertion hole 132 will be formed.

In this respect, it is clear that the present invention is not limited by this embodiment.

Meanwhile, the spacer assembly 140 is disposed between the insulating plate 130 and the vibrating plate A2 to secure a gap between the insulating plate 130 and the vibrating plate A2 to form a space in which ink can flow. It is also possible to include more.

The spacer assembly 140 may include a plate-shaped base plate 144 and an upper spacer US disposed on the base plate 144 and spaced apart from each other.

At this time, the ink is formed so that the ink penetrates through the base plate 144 between the upper spacers (US) and flows through the upper spacers (US) to the ink input hole (131a) side of the insulating plate 130. It is also possible to include the ball 144a.

Meanwhile, as shown in FIG. 5, three upper spacers US 141, 142, and 143 may be provided.

Ink is introduced through the three upper spacers 141, 142, and 143.

Of course, the number of the upper spacers is not limited, but it is sufficient to provide a space in which the ink can flow.

The ink flowing through the upper spacers 141, 142, and 143 flows toward the insulating plate 130 through the ink input hole 144a of the base plate 144.

At this time, the ink is finally introduced into the ink chamber 112 through the ink injection hole (131a) of the insulating plate 130.

Meanwhile, the ink passing through the upper spacers 141, 142, and 143 is pressed by the vibration plate A2 and introduced into the ink chamber 112 as described above.

Of course, the vibration plate A2 is vibrated by the piezoelectric element A1 as described above.

The ink introduced into the ink chamber 112 through this process is charged by the electrode E of the present invention.

In this case, the electrode E of the present invention is inserted from the side of the ink chamber 112 as described above to minimize the contact area with the ink.

Therefore, it is possible to generate stable meniscus even at low voltage without disturbing the flow of the ink.

Meanwhile, in the present embodiment, the electrode E is inserted between the ink chambers 112 in the lower direction in the drawing and then bent and inserted into the ink chambers 112.

However, this shows an example in which the electrode E can be inserted in the side of the ink chamber 112, and the present invention is not limited by this embodiment.

1 is a conceptual diagram showing the principle of electrostatic induction deposition.

2 is a conceptual view illustrating an ink jet head assembly by a piezoelectric actuator method.

3 is a conceptual diagram illustrating an example of the ink jet head assembly.

4 is a conceptual diagram illustrating the concept of an ink jet head assembly having an electrode of the present invention.

5 is an exploded perspective view showing an example of the ink jet head assembly of the present invention.

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

E: electrode 33, 112: ink chamber

N: Nozzle A: Piezoelectric Actuator

Claims (12)

delete delete In the ink jet head assembly 100 for spraying the ink temporarily stored in the ink chamber 112 by electrostatic induction, A head housing 110 having a box shape and having a plurality of ink chambers 112 temporarily storing the ink; An electrode E inserted from one side of the ink chamber 112 and entering the ink chamber 112; A piezoelectric actuator A which is installed at one side of the ink chamber 112 and pressurizes the ink stored in the ink chamber 112; An ink jet head assembly having a method of side-inserting an electrode comprising a ground (G) provided on one side on the other side of the ink chamber (112). The method of claim 3, The electrode (E) has a cylindrical shape, but the tip portion entered into the ink chamber has a pointed shape, the ink jet head assembly is a method of side insertion. The method of claim 3, The electrode (E) is provided with a pair of electrodes, the ink jet head assembly in which the electrodes are inserted side by side from each side of the ink chamber, respectively, and enters into the ink chamber. The method of claim 5, The electrodes E are disposed to be inclined downward toward the ink chamber toward the center of the ink chamber, An ink jet head assembly in which the electrode is side-inserted, the electrode chamber being inclined at an angle of 50 to 60 degrees with respect to the radial plane of the ink chamber. The method of claim 6, An ink jet head assembly in which the electrodes (E) in the ink chamber inner direction are spaced apart from each other at intervals of 1 mm to 1.5 mm in the height direction of the ink chamber. The method of claim 3, Further comprising a nozzle (N) disposed on the lower end of the ink chamber, The nozzle (N) is disposed on the lower end of the ink chamber and has the same center as the depth direction center of the ink chamber, the capillary tube (N1) having a shape in which the same diameter is maintained in the depth direction of the ink chamber, The ink jet head assembly of the method of side-inserting the electrode, characterized in that it comprises an orifice (N2) is arranged in the lower side of the capillary tube (N1) and the shape is reduced toward the lower side. The method of claim 3, The piezoelectric actuator A includes a plate-shaped vibration plate A2 mounted on the upper side of the ink chamber and a piezoelectric element A1 mounted on the vibration plate A2. Ink jet head assembly with side inserts. 10. The method of claim 9, Further comprising a plate-shaped insulating plate 130 is provided between the ink chamber upper side and the vibration plate (A2), An ink jet in which the electrode is inserted side by side, wherein the insulating plate 130 is formed with an ink insertion hole 131a communicating with the ink chamber side and an electrode insertion hole 132 into which the electrode E is inserted. Head assembly. The method of claim 10, The spacer assembly 140 is disposed between the insulating plate 130 and the vibrating plate A2 to form a space in which ink can flow by securing a gap between the insulating plate 130 and the vibrating plate A2. An ink jet head assembly in which the electrode is side-inserted. The method of claim 11, The spacer assembly 140 includes a plate-shaped base plate 144, an upper spacer US disposed on the base plate 144 and spaced apart from each other, An ink injection hole formed to penetrate the base plate 144 between the upper spacers US so that ink passing through the upper spacers US may flow toward the ink injection hole 131a of the insulating plate 130 ( Ink jet head assembly in a manner that the electrode is laterally inserted.

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