101. The inner lateral surface of the first ink transfer passage IP1 and the inner lateral surface of the first nozzle head NZa1 form a continuous surface, and the inner sides of the first ink transfer passage IP1 and the first nozzle head NZa1 may be connected to each other.

Accordingly, ink may be transferred from the chamber to the first nozzle head NZa1 through the first ink transfer passage IP1, and may be discharged from the first nozzle head NZa1 to the outside of the nozzle plate NHD through the bottom surface of the nozzle plate NHD. The first driving electrode E1 may be disposed along the inner lateral surface of the first ink transfer passage IP1.

As an example, the second nozzle portion NZ2 may include a second ink transfer passage IP2 included in the upper plate 102, and a second nozzle head NZa2 included in the lower plate 101. The inner lateral surface of the second ink transfer passage IP2 and the inner lateral surface of the second nozzle head NZa2 form a continuous surface, and the inner sides of the second ink transfer passage IP2 and the second nozzle head NZa2 may be connected to each other. Accordingly, ink may be transferred from the chamber CB to the second nozzle head NZa2 through the second ink transfer passage IP2, and may be discharged from the second nozzle head NZa2 to the outside of the nozzle plate NHD through the bottom surface of the nozzle plate NHD. The second driving electrode E2 may be disposed along the inner lateral surface of the second ink transfer passage IP2.

As an example, the third nozzle portion NZ3 may include a third ink transfer passage IP3 included in the upper plate 102, and a third nozzle head NZa3 included in the lower plate 101. The inner lateral surface of the third ink transfer passage IP3 and the inner lateral surface of the third nozzle head NZa3 form a continuous surface, and the inner sides of the third ink transfer passage IP3 and the third nozzle head NZa3 may be connected to each other. Accordingly, ink may be transferred from the chamber CB to the third nozzle head NZa3 through the third ink transfer passage IP3, and may be discharged from the third nozzle head NZa3 to the outside of the nozzle plate NHD through the bottom surface of the nozzle plate NHD. The third driving electrode E3 may be disposed along the inner lateral surface of the third ink transfer passage IP3.

A first axis AX1 may be a virtual axis extending in a first direction D1 (e.g., direction perpendicular to the bottom surface of the nozzle plate NHD) passing through the center of the first nozzle portion NZ1. A second axis AX2 may be a virtual axis extending in the first direction D1 (e.g., direction perpendicular to the bottom surface of the nozzle plate NHD) passing through the center of the second nozzle portion NZ2. A third axis AX3 may be a virtual axis extending in the first direction D1 (e.g., direction perpendicular to the bottom surface of the nozzle plate NHD) passing through the center of the third nozzle portion NZ3.

The shielding electrodes may include at least a first shielding electrode GE1, a second shielding electrode GE2, and a third shielding electrode GE3. The shielding electrodes may include an additional shielding electrode GE0. As an example, the shielding electrodes may include a ground electrode. The shielding electrodes may be grounded. As an example, each of the shielding electrodes may be apart by a first length h1 from the upper surface of the nozzle plate NHD.

As shown in FIGS. 2 and 3, the first shielding electrode GE1 may be arranged between the first nozzle portion NZ1 and the second nozzle portion NZ2. The first shielding electrode GE1 may be included inside the nozzle plate NHD or the upper plate 102. The first shielding electrode GE1 may be apart from the upper surface of the lower plate 101 or the upper surface of the upper plate 102. The first shielding electrode GE1 may be arranged between the first driving electrode E1 and the second driving electrode E2. The first shielding electrode GE1 may be arranged between the first axis AX1 and the second axis AX2.

The second shielding electrode GE2 may be arranged between the second nozzle portion NZ2 and the third nozzle portion NZ3. The second shielding electrode GE2 may be included inside the nozzle plate NHD or the upper plate 102. The second shielding electrode GE2 may be apart from the upper surface of the lower plate 101 and the upper surface of the upper plate 102. The second shielding electrode GE2 may be arranged between the second driving electrode E2 and the third driving electrode E3. The second shielding electrode GE2 may be arranged between the second axis AX2 and the third axis AX3.

In addition to the first shielding electrode GE1 and the second shielding electrode GE2, the shielding electrodes may further include the additional shielding electrode GE0 according to the number of a nozzle portion. As an example, the shielding electrodes may further include the third shielding electrode GE3, and the third shielding electrode GE3 may be arranged between the third nozzle portion NZ3 and a fourth nozzle portion (not shown). Although the fourth nozzle portion (not shown) is not shown for convenience of illustration, the fourth nozzle portion may be arranged at a position apart in a second direction D2 (e.g., direction crossing the first direction D1) from the third nozzle portion NZ3.

As an example, the additional shielding electrode GE0 may be arranged around the first nozzle portion NZ1. Because description of the additional shielding electrode GE0 may be derived from the description of the other shielding electrodes, description thereof is omitted.

FIG. 4 is a graph showing a voltage measured around a first nozzle head to a third nozzle head NZa3 of the first example.

For reference, in the description of FIG. 4, contents substantially identical or similar to or repeating those described above may be omitted.

Referring to FIG. 4, the voltage around the first nozzle head NZa1 and the third nozzle head NZa3 is measured to be in a range of about 0 V to about 200 V or less. This is a measured value remarkably less than a voltage of about 1000 V or less, which is a voltage around the second nozzle head NZa2, and nearly does not influence inductive electrohydrodynamic driving of the first nozzle portion NZ1 and the third nozzle portion NZ3.

In the first example, voltages inside or around the first nozzle portion NZ1 to the third nozzle portion NZ3 are measured as follows.

TABLE 1

First nozzle portion
Second nozzle portion
Third nozzle portion

(turned-off)
(turned-on)
(turned-off)

Measured
About 400 to about 700
About 1000 to about
About 400 to about 700

voltage (V)

1500

inside nozzle

portion

Around nozzle
About 0 to about 200
About 0 to about 1000
About 0 to about 200

head

Measured

voltage (V)

(However, the measured value is not a voltage at a specific point but denotes a voltage distributed in a specific space and is expressed as a numerical range.)

FIGS. 5 and 6 are graphs showing an electric field shielding effect according to a first length h1 of the first example.

For reference, in the description of FIGS. 5 and 6, contents substantially identical or similar to or repeating those described above may be omitted.

A trench height of an x axis in FIG. 5 may denote a distance such as the first length h1 between each of the shielding electrodes and the upper surface of the nozzle plate NHD. A y axis in FIG. 5 denotes an intensity of an electric field measured in a neighboring nozzle portion adjacent to a nozzle portion that is turned on, and specifically, may be an intensity of an electric field measured around a neighboring nozzle head adjacent to the nozzle portion that is turned on.

As shown in FIG. 5, in the case where a distance between each of the shielding electrodes and the upper surface of the nozzle plate NHD is in a range of about 400 μm to about 500 μm, it may be determined that a shielding effect due to the shielding electrode is a maximum.

As an example, in the case where a driving voltage is applied to the second driving electrode E2 of the first example, the first length h1 may be in a range of about 400 μm to about 500 μm. In the case where the first length h1 is in a range of about 400 μm to about 500 μm, an intensity of an electric field around the first nozzle head NZa1 and the third nozzle head NZa3 is minimized.

A trench height in an x axis in FIG. 6 may denote a distance such as the first length h1 between each of the shielding electrodes and the upper surface of the nozzle plate NHD. The y axis in FIG. 6 denotes a ratio of an intensity of an electric field measured in a neighboring nozzle portion adjacent to a nozzle portion that is turned on/off, and specifically, may be a ratio of an intensity of an electric field measured around a neighboring nozzle head adjacent to the nozzle portion that is turned on/off.

Generally, in the case where the ratio of the intensity of the above electric field is about 30 or less, it may be determined that the process is possible. Accordingly, referring to FIG. 6, the first length h1 may be in a range of about 100 μm to about 500 μm, and preferably, may be in a range of about 300 μm to about 400 μm.

Finally, the first length h1 meeting all of the preferable conditions of FIGS. 5 and 6 may be about 400 μm.

FIG. 7 is a schematic cross-sectional view of a second example of the region A of FIG. 1, and FIG. 8 is a schematic perspective view of the second example of the region A of FIG. 1.

For reference, in the description of FIGS. 7 and 8, contents substantially identical or similar to or repeating those described above may be omitted.

The shielding electrodes may include at least the first shielding electrode GE1, the second shielding electrode GE2, and the third shielding electrode GE3. The shielding electrodes may include the additional shielding electrode GE0. As an example, the shielding electrodes may be ground electrodes. The shielding electrodes may be grounded. As an example, each of the shielding electrodes may be apart by a second length h2 from the upper surface of the nozzle plate NHD. The second length h2 may be greater than the first length h1.

As shown in FIGS. 7 and 8, the first shielding electrode GE1 may be arranged between the first nozzle portion NZ1 and the second nozzle portion NZ2. The first shielding electrode GE1 may be included inside the nozzle plate NHD or the upper plate 102. The first shielding electrode GE1 may be in contact with the upper surface of the lower plate 101 and be apart from the upper surface of the upper plate 102. The first shielding electrode GE1 may be arranged between the first driving electrode E1 and the second driving electrode E2. The first shielding electrode GE1 may be arranged between the first axis AX1 and the second axis AX2.

The second shielding electrode GE2 may be arranged between the second nozzle portion NZ2 and the third nozzle portion NZ3. The second shielding electrode GE2 may be included inside the nozzle plate NHD or the upper plate 102. The second shielding electrode GE2 may be in contact with the upper surface of the lower plate 101 and be apart from the upper surface of the upper plate 102. The second shielding electrode GE2 may be arranged between the second driving electrode E2 and the third driving electrode E3. The second shielding electrode GE2 may be arranged between the second axis AX2 and the third axis AX3.

The shielding electrodes may further include the third shielding electrode GE3 and the additional shielding electrode GE0 in addition to the first shielding electrode GE1 and the second shielding electrode GE2. The third shielding electrode GE3 and the additional shielding electrode GE0 may also be in contact with the upper surface of the lower plate 101 and be apart from the upper surface of the upper plate 102.

In the second example, voltages inside or around the first nozzle portion NZ1 to the third nozzle portion NZ3 are measured as follows.

TABLE 2

First nozzle portion
Second nozzle portion
Third nozzle portion

(turned-off)
(turned-on)
(turned-off)

Measured
About 600 to about
About 1100 to about
About 600 to about

voltage (V)
1000
1500
1000

inside nozzle

portion

Around nozzle
About 0 to about 800
About 0 to about 1200
About 0 to about 800

head

Measured

voltage (V)

However, the measure value is not a voltage at a specific point but denotes a voltage distributed in a specific space and is expressed as a numerical range.)

According to Table 2, it may be determined that a magnetic field generated from the second driving electrode E2 has a low influence on the first nozzle portion NZ1 and the third nozzle portion NZ3 due to the first shielding electrode GE1 and the second shielding electrode GE2. The voltage of the inside of the first nozzle portion NZ1 and the third nozzle portion NZ3 is measured to be in a range of about 600 V to about 1000 V. This is a numerical value less than a voltage in a range of about 1100 V to about 1500 of the inside of the second nozzle portion NZ2.

The voltage around the first nozzle head NZa1 and the third nozzle head NZa3 is measured to be in a range of about 0 V to about 800 V. This is a measured value relatively less than a voltage of about 1200 V or less, which is a voltage around the second nozzle head NZa2, and does not influence inductive electrohydrodynamic driving of the first nozzle portion NZ1 and the third nozzle portion NZ3.

However, it may be determined that measured voltages shown in Table 2 are greater than measured voltages shown in Table 1. Accordingly, the position of the shielding electrode of the first example has a greater electric field shielding effect than the position of the shielding electrode of the second example.

FIG. 9 is a schematic cross-sectional view of a third example of a region A of FIG. 1, and FIG. 10 is a schematic perspective view of the third example of a region A of FIG. 1.

For reference, in the description of FIGS. 9 and 10, contents substantially identical or similar to or repeating those described above may be omitted.

The shielding electrodes may include at least a first shielding electrode GE1, a second shielding electrode GE2, and a third shielding electrode GE3. The shielding electrodes may include an additional shielding electrode GE0. As an example, the shielding electrodes may include a ground electrode. The shielding electrodes may be grounded. As an example, the height of each of the shielding electrodes may be the thickness of the nozzle plate NHD. As an example, the height of each of the shielding electrodes may be a third length h3, and the third length h3 may be the thickness of the nozzle plate NHD. The third length h3 may be greater than the first length h1. The third length h3 may be greater than the second length h2.

As shown in FIGS. 9 and 10, the first shielding electrode GE1 may be arranged between the first nozzle portion NZ1 and the second nozzle portion NZ2. The first shielding electrode GE1 may be included inside the nozzle plate NHD. The first shielding electrode GE1 may be in contact with the bottom surface of the nozzle plate NHD and be in contact with the upper surface of the upper plate 102. Specifically, the first shielding electrode GE1 may extend from the bottom surface of the nozzle plate NHD to the upper surface of the nozzle plate NHD. The first shielding electrode GE1 may extend from the lower plate 101 to the upper surface of the upper plate 102. The first shielding electrode GE1 may be arranged between the first driving electrode E1 and the second driving electrode E2. The first shielding electrode GE1 may be arranged between the first axis AX1 and the second axis AX2.

The second shielding electrode GE2 may be arranged between the second nozzle portion NZ2 and the third nozzle portion NZ3. The second shielding electrode GE2 may be included inside the nozzle plate NHD. The second shielding electrode GE2 may be in contact with the bottom surface of the nozzle plate NHD and be in contact with the upper surface of the upper plate 102. Specifically, the second shielding electrode GE2 may extend from the bottom surface of the nozzle plate NHD to the upper surface of the nozzle plate NHD. The second shielding electrode GE2 may extend from the lower plate 101 to the upper surface of the upper plate 102. The second shielding electrode GE2 may be arranged between the second driving electrode E2 and the third driving electrode E3. The second shielding electrode GE2 may be arranged between the second axis AX2 and the third axis AX3.

The shielding electrodes may further include the third shielding electrode GE3 and the additional shielding electrode GE0 in addition to the first shielding electrode GE1 and the second shielding electrode GE2. The third shielding electrode GE3 and the additional shielding electrode GE0 may also extend from the bottom surface of the nozzle plate NHD to the upper surface of the nozzle plate NHD. The third shielding electrode GE3 and the additional shielding electrode GE0 may also extend from the lower surface of the lower plate 101 to the upper surface of the upper plate 102.

FIGS. 11 and 12 are graphs showing an electric field shielding effect according to a height to each of shielding electrodes.

For reference, in the description of FIGS. 11 and 12, contents substantially identical or similar to or repeating those described above may be omitted.

A ground height of an x axis in FIG. 11 may mean a height of each of the shielding electrodes. A height of each of the shielding electrodes may mean a length in the first direction D1 shown in the above-described drawings. A height of each of the shielding electrodes may mean a length in a thickness direction of the nozzle plate NHD. The y axis in FIG. 11 denotes a ratio of an intensity of an electric field measured by a neighboring nozzle portion adjacent to a nozzle portion that is turned on/off, and specifically, may be a ratio of an intensity of an electric field measured around a neighboring nozzle head adjacent to the nozzle portion that is turned on/off.

As shown in FIG. 11, it may be determined that, as a height of each of the shielding electrodes increases, a ratio of an intensity of an electric field measured around a neighboring nozzle head adjacent to a nozzle portion that is turned on/off, is reduced. For example, it may be determined that, as a ratio of an intensity of an electric field measured around a neighboring nozzle head adjacent to a nozzle portion that is turned on/off, is reduced, a shielding effect increases. Accordingly, for greater shielding effect, a height of each of the shielding electrodes needs to increase.

As shown in FIG. 11, a height of each of the shielding electrodes may be about 600 μm. As an example, the height of each of the shielding electrodes may be substantially equal to the thickness of the nozzle plate NHD as in the third example. The height of each of the shielding electrodes may increase until the height is substantially equal to the thickness of the nozzle plate NHD as in the third example.

Numerical values shown in FIG. 11 are summarized in Table as follows.

TABLE 3

Ground Height [μm]
On[V/m]
Off[V/m]
Ratio[%]

100
1.045E+07
1.2E+06
11.6

200
1.043E+07
7.3E+05
7.0

300
1.037E+07
5.0E+05
4.8

400
1.033E+07
3.3E+05
3.2

500
1.031E+07
2.1E+05
2.0

600
1.029E+07
1.2E+05
1.2

A ground height of an x axis in FIG. 12 may mean a height of each of the shielding electrodes. A height of each of the shielding electrodes may mean a length in the first direction D1 shown in the above-described drawings. A height of each of the shielding electrodes may mean a length in a thickness direction of the nozzle plate NHD. A y axis of FIG. 12 may be a ratio of a reduced amount of an electric field measured by a neighboring nozzle portion adjacent to a nozzle portion that is turned on.

As shown in FIG. 12, it may be determined that, as a height of each of the shielding electrodes increases, a ratio of a reduced amount of an electric field measured by a neighboring nozzle portion adjacent to a nozzle portion that is turned on is reduced. For example, it may be determined that, as a ratio of the amount of an electric field measured by a neighboring nozzle portion adjacent to a nozzle portion that is turned on is reduced, a shielding effect increases. Accordingly, for greater shielding effect, a height of each of the shielding electrodes needs to increase.

As shown in FIG. 12, a height of each of the shielding electrodes may be about 600 μm. As an example, the height of each of the shielding electrodes may be substantially equal to the thickness of the nozzle plate NHD as in the third example. The height of each of the shielding electrodes may increase until the height is substantially equal to the thickness of the nozzle plate NHD as in the third example.

Numerical values shown in FIG. 12 are summarized in Table as follows.

TABLE 4

Ground Height [μm]
On[V/m]
Ratio[%]

100
1.045E+07
100.0

200
1.043E+07
99.8

300
1.037E+07
99.2

400
1.033E+07
98.8

500
1.031E+07
98.6

600
1.029E+07
98.4

FIG. 13 is a schematic cross-sectional view of a fourth example of the region A of FIG. 1, and FIG. 14 is a schematic perspective view of the fourth example of the region A of FIG. 1.

For reference, in the description of FIGS. 13 and 14, contents substantially identical or similar to or repeating those described above may be omitted.

The shielding electrodes may include at least a first shielding electrode GE1, a second shielding electrode GE2, and a third shielding electrode GE3. The shielding electrodes may include an additional shielding electrode GE0. As an example, the shielding electrodes may include a ground electrode. The shielding electrodes may be grounded.

As an example, each of the shielding electrodes may be disposed on the upper surface of the nozzle plate NHD. The lower surface of each of the shielding electrodes may be in contact with the upper surface of the nozzle plate NHD.

As shown in FIGS. 13 and 14, the first shielding electrode GE1 may be arranged between the first nozzle portion NZ1 and the second nozzle portion NZ2. The first shielding electrode GE1 may be disposed on the upper surface of the nozzle plate NHD. Depending on the case, the first shielding electrode GE1 may be located in the chamber CB. The first shielding electrode GE1 may be in contact with the upper surface of the nozzle plate NHD. The first shielding electrode GE1 may be arranged between the first driving electrode E1 and the second driving electrode E2. The first shielding electrode GE1 may be arranged between the first axis AX1 and the second axis AX2.

The second shielding electrode GE2 may be arranged between the second nozzle portion NZ2 and the third nozzle portion NZ3. The second shielding electrode GE2 may be disposed on the upper surface of the nozzle plate NHD. Depending on the case, the second shielding electrode GE2 may be located in the chamber CB. The second shielding electrode GE2 may be in contact with the upper surface of the nozzle plate NHD. The second shielding electrode GE2 may be arranged between the second driving electrode E2 and the third driving electrode E3. The second shielding electrode GE2 may be arranged between the second axis AX2 and the third axis AX3.

The shielding electrodes may further include the third shielding electrode GE3 and the additional shielding electrode GE0 in addition to the first shielding electrode GE1 and the second shielding electrode GE2. The third shielding electrode GE3 and the additional shielding electrode GE0 may also be disposed on the upper surface of the nozzle.

In the fourth example, voltages inside or around the first nozzle portion NZ1 to the third nozzle portion NZ3 are measured as follows.

TABLE 5

First nozzle portion
Second nozzle portion
Third nozzle portion

(turned-off)
(turned-on)
(turned-off)

Measured
About 100 to about 300
About 1000 to about
About 100 to about 300

voltage (V)

1500

inside nozzle

portion

Around nozzle
About 0 to about 200
About 0 to about 1000
About 0 to about 200

head

Measured

voltage (V)

(However, the measured value is not a voltage at a specific point but denotes a voltage distributed in a specific space and is expressed as a numerical range.)

According to Table 5, it may be determined that a magnetic field generated from the second driving electrode E2 has a low influence on the first nozzle portion NZ1 and the third nozzle portion NZ3 due to the first shielding electrode GE1 and the second shielding electrode GE2. The voltage of the inside of the first nozzle portion NZ1 and the third nozzle portion NZ3 is measured to be in a range of about 100 V to about 300 V. This is a numerical value less than a voltage in a range of about 1000 V to about 1500 of the inside of the second nozzle portion NZ2.

The voltage around the first nozzle head NZa1 and the third nozzle head NZa3 is measured to be in a range of about 0 V to about 200 V. This is a measured value relatively less than a voltage of 1000 V or less, which is a voltage around the second nozzle head NZa2, and does not influence inductive electrohydrodynamic driving of the first nozzle portion NZ1 and the third nozzle portion NZ3.

However, it may be determined that measured voltages shown in Table 5 are far less than measured voltages shown in Table 1 and Table 2. Accordingly, the position of the shielding electrode of the fourth example has a greater electric field shielding effect than the position of the shielding electrode of the first example and the second example.

FIG. 15 is a schematic cross-sectional view of a fifth example of the region A of FIG. 1, and FIG. 16 is a schematic perspective view of the fifth example of the region A of FIG. 1.

For reference, in the description of FIGS. 15 and 16, contents substantially identical or similar to or repeating those described above may be omitted.

As shown in FIGS. 15 and 16, partition walls may be arranged between the shielding electrodes and the nozzle plate NHD. As an example, the inkjet printing head 100 of the fifth example may further include the partition walls arranged between the shielding electrodes and the nozzle plate NHD.

The partition walls may include at least a first partition wall and a third partition wall. The partition walls may further include an additional partition wall. As an example, the partition walls may be disposed on the upper surface of the nozzle plate NHD.

The shielding electrodes may include at least a first shielding electrode GE1, a second shielding electrode GE2, and a third shielding electrode GE3. The shielding electrodes may include an additional shielding electrode GE0. As an example, the shielding electrodes may include a ground electrode. The shielding electrodes may be grounded.

As an example, the first partition wall may be arranged between the first nozzle portion NZ