KR101348024B1 - Electro-hydrodynamic ink jet device - Google Patents

Abstract

The present invention relates to an electro-hydrodynamic inkjet device which includes a discharge head with at least one nozzle where ink droplets are discharged; an object which faces the nozzle and where the ink droplets discharged via the nozzle; a power supplier which is connected to the discharge head or the object and which supplies a first voltage; a random waveform generating device which is connected to the discharge head or the object and which generates a second voltage to be supplied to the object of the discharge head; a voltage amplifying device which is connected to the random waveform generating device and which amplifies the second voltage and supplies the amplified second voltage to the object or the discharge head; and a control unit which is connected to the power supplier and the random waveform generating device and which controls the state that the first or second voltage is supplied to the discharge head or the object. The control unit controls the first and second voltages to have identical polarity when the discharge head or the object is moved or can improve the distance between the discharge head or the object. Therefore, the undesired discharge of the ink droplets is prevented during the movement of the discharge head.

Description

[0001] ELECTRO-HYDRODYNAMIC INK JET DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrohydraulic inkjet device, and more particularly, to reduce the cost of the device by separating the voltage applied to the discharge head or the nozzle and the voltage applied to the discharged object, and prevent unwanted discharge of ink droplets. It relates to an electrohydraulic inkjet device capable of.

An electro-hydrodynamic (EHD) inkjet printing system is an apparatus for electrostatic force acting on a fluid to cause electrification when a fluid is exposed to a strong local electric field and to perform patterning on a substrate using such electrical mutual attraction, Unlike a head of a conventional piezo inkjet printing system, it is a device that performs a pattern on a substrate based on the electrostatic attraction force induced by the electric charge injected into the ink.

As with conventional inkjet printing equipment, there is an advantage of minimizing material waste by ejecting the correct amount of ink at the correct location. Electrohydrodynamic inkjet technology is also called electrostatic inkjet technology, and it has an advantage that patterning of high viscosity and fine line width is possible compared with the conventional piezo inkjet method by using electrostatic force.

Also, it is a new next-generation printing technology evaluated because it has high process stability due to few nozzle clogging phenomena. These advantages are expected to be applied to various printing electronic industries such as RFID, process technology of solar cell, and manufacturing process technology of electronic device having flexible substrate.

For electrohydraulic inkjet, the meniscus shape should be controlled from the nozzle. For this, a slight positive pressure may be applied to the head using the height of the fluid height, a slight positive pressure may be applied using air pressure, or a syringe pump may be used. Therefore, the force for discharging is caused by the sum of the electric attractive force and the pressure applied to the fluid.

An electric field must be applied to eject ink from an electrohydraulic inkjet apparatus. The electric field can apply a high voltage (hundreds to several kV) direct current (DC) voltage. When a DC voltage is applied, cone jet type jetting is formed at the tip of the nozzle.

However, if a direct current voltage is applied, it is difficult to control the frequency of on-off drop of ink droplets to be ejected and on-off control thereof. To solve this problem, DC + AC or AC is applied to use the technique.

A pulse is applied to the ink jet apparatus for ejecting the ink at a desired position. The shape of the pulse may be a square wave shape, a trapezoidal shape, or the like.

In order to actually print a pattern, a pattern generator may be used to make a pulse when there is a trigger signal at the position of the pattern. After the pulse of the desired shape is made into an arbitrary function generator, it is amplified by an amplifier. That is, DC + AC is made into an arbitrary waveform generator and then amplified using an amplifier.

The DC voltage is the voltage to hold the meniscus of the ink and the pulse is actually the voltage when the pulse is applied. These pulses can be generated by using a counter, digital IO (Digital IO), etc., and when the shape of the pulse is various, a pulse generated by an arbitrary waveform generator or a pattern generator is generated using a pulse trigger You. The generated voltage is amplified through an amplifier.

However, the conventional AC + DC driving method has the following problems. The voltage is up to several kV and a high voltage amplifier is used to give various shapes of pulses. In this case, the higher the voltage, the higher the price of the device.

Further, when DC offset exists in the high voltage amplifier, the required power requirement is also increased, and there is a problem that the power is increased in addition to the voltage increase.

When the discharge head or the nozzle moves to print a pattern to be printed, there is also a problem that undesirable discharge occurs during movement. Therefore, a voltage applying method capable of discharging ink only at a position where a pulse is applied is needed.

In addition, a device having a plurality of nozzles in an ejection head can reduce the cost of the apparatus, and a control technique capable of accurately ejecting ink only at a point where pulses are applied is required.

In addition, the existing electro-hydraulic inkjet equipment also has a problem that ink droplets are ejected to an unwanted area or pattern when the distance between the substrate and the discharge head / nozzle is changed.

An embodiment of the present invention provides an electrohydraulic ink jet apparatus capable of separating a voltage applied to a discharge head or a nozzle and a voltage applied to a discharge object.

An embodiment of the present invention provides an electrohydrodynamic inkjet apparatus capable of reducing the manufacturing cost of a device by separately applying two types of voltages having different potentials.

One embodiment of the present invention provides an electrohydraulic inkjet device in which ink can be ejected accurately only at the point where a pulse is applied.

One embodiment of the present invention provides an electrohydraulic ink jet apparatus in which ink is not ejected while the ejection head or the nozzle is moving.

One embodiment of the present invention provides an electrohydraulic inkjet device capable of preventing ink droplets from being discharged to an undesired area even when the distance between the discharge head / nozzle and the discharged object is changed.

According to an aspect of the present invention, there is provided an electrohydraulic inkjet apparatus including: an ejection head having at least one nozzle through which ink droplets are ejected; A protrusion opposed to the nozzle and on which ink droplets ejected from the nozzle are printed; A power supply connected to the ejection head or the object to apply a first voltage; An arbitrary waveform generator for generating a second voltage to be applied to the object or the discharge head; A voltage amplifier connected to the arbitrary waveform generator for amplifying the second voltage and applying the second voltage amplified to the object or the discharge head; And a control unit connected to the power supply and the arbitrary waveform generator and configured to control a state in which the first voltage or the second voltage is applied to the discharge head or the discharged object. When one of the discharged objects moves, the first voltage and the second voltage are controlled to have the same polarity, or the distance between the discharge head and the discharged object is increased, and the first voltage is a direct current. Voltage, and the second voltage is a pulse voltage or a direct current voltage having the same polarity as the first voltage, and when the second voltage is a pulse voltage, the potential of the same polarity as the first voltage and the first voltage are different from the first voltage. It can have both polarity potentials.

By forming as described above, it is possible to prevent the ink from being discharged from the nozzle which is to be discharged or not discharged to an undesired position while the discharge head or the nozzle is moving.

The controller may be configured to separate a voltage applied to the discharge head and a voltage applied to the discharged object, or when any one of the first voltage and the second voltage is applied to the discharge head, the first voltage or The other one of the second voltages may be controlled to be applied.

When the second voltage is a pulse voltage, the absolute value of the potential having the same polarity as the first voltage is smaller than the absolute value of the potential having a polarity different from the first voltage, and the second voltage is the DC voltage. The absolute value of the potential of the second voltage may be smaller than the absolute value of the potential of the first voltage.

delete

delete

The control unit is configured to apply a potential having the same polarity as the first voltage among the second voltages that are pulse voltages to either the discharge head or the discharged object when either the discharge head or the discharged object moves. Can be controlled.

When the second voltage is a pulse voltage, the discharge prevention voltage and the discharge voltage may be sequentially formed, and the discharge prevention voltage may have the same polarity as the first voltage, and the discharge voltage may have a different polarity from the first voltage.

The potential difference between the first voltage and the discharge preventing voltage may be smaller than the potential difference between the first voltage and the discharge voltage.

As described above, since the electrohydraulic inkjet apparatus according to an embodiment of the present invention separates and applies the DC voltage and the pulse voltage, it is possible to use a low-cost high voltage power supplier and a low-cost amplifier, have.

The electrohydraulic inkjet apparatus according to an embodiment of the present invention uses a driving method in which a DC voltage power supplier and a low voltage power amplifier are combined, thereby lowering the price requirement of the apparatus.

In the electrohydraulic inkjet device according to the embodiment of the present invention, since the ink is not discharged while the discharge head or the nozzle is moved, the printing precision can be increased and the waste of ink can be reduced.

The electrohydraulic inkjet device according to an embodiment of the present invention can accurately control the ejection nozzle and the non-ejection nozzle.

The electrohydraulic inkjet device according to the embodiment of the present invention can prevent the ink droplets from being discharged to the undesired area even if the distance between the discharge head / nozzle and the discharged object is changed.

1 is a perspective view schematically showing a configuration of an electrohydraulic inkjet apparatus according to an embodiment of the present invention.
2 is a diagram showing voltage waveforms applied to the inkjet apparatus according to FIG.
3 is a schematic view showing the configuration of an electrohydraulic inkjet apparatus according to another embodiment of the present invention.
4 is a diagram showing voltage waveforms applied to the inkjet apparatus according to FIG.
FIG. 5 is a diagram illustrating another example of a voltage waveform applied to the inkjet apparatus according to FIGS. 1 and 3.
6 is a partially enlarged view of a pattern and the pattern printed using the inkjet apparatus according to FIGS. 1 and 3.
7 is a flowchart illustrating a method of applying a voltage to the inkjet apparatus according to FIGS. 1 and 3.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the embodiments. Like reference symbols in the drawings denote like elements.

1 is a perspective view schematically showing the configuration of an electro-hydraulic inkjet device according to an embodiment of the present invention, FIG. 2 is a view showing a voltage waveform applied to the inkjet device according to FIG. 1, and FIG. 4 is a view schematically showing a configuration of an electrohydraulic ink jet device according to another embodiment, FIG. 4 is a view showing a voltage waveform applied to the ink jet device according to FIG. 3, and FIG. 5 is an ink jet according to FIGS. 1 and 3. 6 shows another example of the voltage waveform applied to the apparatus, FIG. 6 is an enlarged view of a pattern and a pattern printed using the ink jet apparatus according to FIGS. 1 and 3, and FIG. 7 is an ink jet according to FIGS. 1 and 3. A flow chart illustrating a method of applying a voltage to a device.

1 and 2, an electrohydraulic inkjet apparatus 100 according to an embodiment of the present invention includes an ejection head 120 having at least one nozzle 125 through which ink droplets are ejected, a nozzle 125 A power supply 140 which is connected to the object 130 and applies a first voltage to the inkjet head 130 and which is to be applied to the ejection head 120; A voltage amplifier 160 connected to the arbitrary waveform generator 150 for amplifying the second voltage and applying the second voltage amplified to the discharge head 120, And a control unit 170 connected to the supply source 140 and the arbitrary waveform generator 150 and controlling the state in which the first voltage or the second voltage is applied to the discharge head 120 or the object 130. [ have.

A purge / suction controller 110 (Purge / Suction Controller) for injecting or supplying ink may be connected to the discharge head 120. The purge / suction controller 110 may control the injection of ink into the discharge head 120 or the nozzle 125 or may control the amount of ink to be supplied. For this, the purge / suction controller 110 may be connected to the controller 170.

A discharge object 130 is positioned below the discharge head 120 or the nozzle 125, and a pattern to be printed on the object 130 is printed. Here, the object 130 is preferably formed of a substrate or the like. As described above, the protrusion 130 is preferably formed of a conductor so that a voltage can be applied to the protrusion 130.

In order to print a complex pattern, the discharge head 120 / the nozzle 125 or the object 130 may be moved in the X-axis direction or the Y-axis direction, and a driving unit (not shown) may be provided.

The electrohydraulic inkjet apparatus 100 according to an embodiment of the present invention is different from the conventional art in that a voltage applied to the ejection head 120 / nozzle 125 and a voltage applied to the object 130 are separated . 1, a power supplier 140 is connected to the object 130, and a waveform generator 150 (Function Generator) is connected to the discharge head 120 / ) Or a voltage amplifier 160 (Voltage Amplifier) are connected.

The control unit 170 separates the voltage applied to the discharge head 120 from the voltage applied to the discharge object 130 or the voltage applied to the discharge head 120 / Or the second voltage is applied, the other one of the first voltage and the second voltage may be applied to the object.

As described above, it is possible to reduce the cost of the electrohydraulic inkjet apparatus by separating the voltage applied to the ejection head 120 / nozzle 125 and the object. That is, the inkjet apparatus 100 can be driven using a low-cost power supply and a low-cost voltage amplifier.

The power supply 140 can use a low-cost power supply, and generates a direct-current voltage to apply a direct-current voltage to the object 130. At this time, the DC voltage applied to the power supply 140 may be about several hundreds (V) to several thousands (V).

The operation of the arbitrary waveform generator 150 is controlled by the controller 170, and a desired waveform is generated by communicating with the controller 170 using the USB. The waveform generated from the arbitrary waveform generator 150 may be amplified through the voltage amplifier 160 by about 1000 times and applied to the ejection head 120 / nozzle 125. Unlike the prior art, the voltage amplifier 160 according to an embodiment of the present invention uses a low-cost amplifier.

The second voltage generated in the arbitrary waveform generator 150 is a pulse voltage. 2, a DC voltage 2 generated in the power supply 140 is applied as a first voltage to the object 130, and a pulse voltage 1 is applied to the discharge head 120 as a second voltage Lt; / RTI > The electrohydraulic inkjet apparatus 100 according to an embodiment of the present invention may be configured to apply a DC + AC voltage to the ejection head 120 even though the voltage applied to the object 130 and the ejection head 120 / The same effect as in (3) can be obtained.

Here, the first voltage 2 generated by the power supplier 140 and the second voltage 1 generated by the arbitrary waveform generator 150 may have different polarities. Referring to FIG. 2, the first voltage 2 has a positive potential, while the second voltage 1 has a negative potential. As described above, the potential difference between the first voltage (2) and the second voltage (1) can be increased by having the first voltage (2) and the second voltage (1) The larger the potential difference is, the more ink droplets can be discharged.

The first voltage (2) and the second voltage (1) may have a polarity capable of generating attractive force between the ink droplet and the object (130). Since a voltage having a different polarity is applied, a pulling force (attractive force, attractive force) acts between the discharge head 120 and the object 130 to discharge the ink. The ejection of the ink occurs when a pulse having a potential in the second voltage (1) is generated. 2, a pulse having a potential value is generated at a constant time interval. When such a pulse is generated, a potential difference with respect to the first voltage (2) increases and attraction occurs, so that the ink is ejected .

Meanwhile, the controller 170 may adjust the size of the first voltage 2 to maintain the meniscus formed at the end of the nozzle 125 by the ink droplet. The first voltage 2 having the DC voltage may also function to maintain the shape of the meniscus without ejecting the ink from the nozzle 125. In order to maintain the meniscus, The polarity, and the time of the first voltage generated in the power supply 140. [0033] FIG.

On the other hand, the first voltage and the second voltage may be applied to the ejection head / nozzle and the object, respectively. Will be described with reference to Figs. 3 and 4. Fig.

The electrohydrodynamic inkjet apparatus 200 according to another embodiment of the present invention shown in FIG. 3 includes an ejection head 220 having at least one nozzle 225 through which ink droplets are ejected, a nozzle 225 facing the ejection head 220 A power supply 240 connected to the ejection head 220 / nozzle 225 to apply a first voltage, a power supply 240 connected to the ejection head 220 / nozzle 225 to be applied to the object 230, A voltage amplifier 260 connected to the arbitrary waveform generator 250 for amplifying the second voltage and applying the second voltage amplified to the object 230, A controller connected to the power supply 240 and the arbitrary waveform generator 250 for controlling the state in which the first voltage or the second voltage is applied to the ejection head 220 / the nozzle 225 or the object 230 270).

Compared with the apparatus 100 shown in FIG. 1, the apparatus 200 shown in FIG. 3 is configured such that the power supply 240 is connected to the discharge head 220 / nozzle 225 to apply a first voltage, Only the difference in which the arbitrary waveform generator 250 is connected to the second voltage 230 is applied to the second switch 230, and the rest of the configuration is the same.

The control unit 270 separates the voltage applied to the ejection head 220 and the nozzle 225 from the voltage applied to the ejection head 230 or the nozzle 225, Or the second voltage is applied, the other one of the first voltage and the second voltage may be controlled to be applied to the object.

As described above, it is possible to reduce the cost of the electrohydraulic inkjet apparatus by separating the voltage applied to the ejection head 220 / nozzle 225 and the object 230. That is, the inkjet apparatus 200 can be driven using a low-cost power supply and a low-cost voltage amplifier.

4, the DC voltage 4 generated by the power supply 240 is applied as the first voltage to the ejection head 220 / nozzle 225, and the pulse voltage 5 Can be applied as the second voltage. The electrohydraulic inkjet apparatus 200 according to another embodiment of the present invention is capable of applying DC + AC in a conventional manner even when a voltage applied to the object 230 and the ejection head 220 / The same effect as in (6) can be obtained.

Here, the first voltage 4 generated by the power supplier 240 and the second voltage 5 generated by the arbitrary waveform generator 250 may have different polarities. Referring to FIG. 4, the first voltage 4 has a positive potential, while the second voltage 5 has a negative potential. In this manner, the potential difference between the first voltage 4 and the second voltage 5 can be made large by making the potentials of the first and second voltages 4 and 5 different (opposite to each other) The larger the potential difference is, the more ink droplets can be discharged.

In addition, the first voltage 4 and the second voltage 5 may have a polarity capable of generating a attraction force between the ink droplet and the object 230. Since a voltage having a different polarity is applied, a pulling force (attracting force and attracting force) between the ejection head 220 and the object 230 can act to eject the ink. The ejection of ink occurs when a pulse having a potential in the second voltage 5 occurs. 4, a pulse having a potential value is generated at a constant time interval. When such a pulse is generated, a potential difference between the first voltage 4 and the first voltage 4 is increased and a attraction force is generated. .

Meanwhile, the controller 270 may adjust the size of the first voltage 4 to maintain the meniscus formed at the end of the nozzle 225 by the ink droplet. The first voltage 4 having the DC voltage may also function to maintain the shape of the meniscus without ejecting the ink from the nozzle 225. In order to maintain the meniscus, The polarity, and the time of the first voltage generated in the power supplier 240. [0033] FIG.

The controller 170 or 270 of the electrohydraulic inkjet apparatus 100 or 200 according to the present invention can separate the voltage applied to the ejection heads 120 and 220 and the voltage applied to the protrusions 130 and 230 or the voltage applied to the ejection heads 120 and 220 When one of the first voltage (2,4) or the second voltage (1,5) is applied, the other one of the first voltage (2,4) or the second voltage (1,5) Can be controlled to be applied.

6 shows an enlarged view of a pattern printed by the electrohydraulic inkjet device 100 and 200 and a portion of the pattern according to the present invention. More precisely, FIG. 6 shows a pattern printed using the apparatus 100 in which a DC voltage is applied to the object to be discharged 130 and a pulse is applied to the discharge head 120 / nozzle 125 as shown in FIG. 1. Is a picture.

Meanwhile, the electrohydraulic inkjet apparatus 100 according to the exemplary embodiment of FIG. 1 may prevent the ink from being discharged while the discharge head 120 or the nozzle 125 is moved. To this end, the control unit 170 of the electro-hydraulic inkjet apparatus 100 is such that when either the discharge head 120 or the discharged object 130 moves, the first voltage and the second voltage have different waveforms. Can be controlled. Alternatively, the controller 170 may control the first voltage and the second voltage to have the same polarity when one of the discharge head 110 and the discharged object 130 moves, or the discharge head 110 and the pitot The distance between the output 130 may be controlled to increase.

By forming as described above, it is possible to prevent the ink from being discharged from the nozzle which is to be discharged or not discharged to an undesired position while the discharge head or the nozzle is moving.

As described above, the control unit 170 separates the voltage applied to the discharge head 120 and the voltage applied to the discharged object 130, or any of the first voltage or the second voltage is applied to the discharge head 120. When one is applied, the discharge object 130 may be controlled to apply the other of the first voltage or the second voltage.

As illustrated in FIG. 5, the first voltage 8 applied to the discharged object 130 is a DC voltage, and the second voltage 7 applied to the discharge head 120 / nozzle 125 has a pulse voltage. Can be. Here, unlike the voltage waveforms shown in FIGS. 2 and 4, a second applied to the discharge head 120 / nozzle 125 to prevent ink from being discharged during the movement of the discharge head 120 / nozzle 125. The voltage 7 may be a pulse voltage having both the potential of the same polarity as the first voltage 8 and the potential of the polarity different from the first voltage 8. That is, in FIG. 5, the second voltage 7 has both a potential A of the same polarity as the first voltage 8 and a potential B of a different polarity from the first voltage 8.

On the other hand, although not shown, the second voltage 7 applied to the discharge head 120 / nozzle 125 in order to prevent the ink is discharged during the movement of the discharge head 120 / nozzle 125 is the discharged object 130 It may also be a current flow voltage having the same polarity as the first voltage 8 applied to).

In addition, the second voltage 7 may have an absolute value of the potential A having the same polarity as the first voltage 8 less than an absolute value of the potential B having a different polarity than the first voltage 8. . The second voltage 7 has a discharge preventing voltage A and a discharge voltage B in this order. The discharge preventing voltage A has the same polarity as the first voltage 8 and the discharge voltage B is the first voltage. It may have a different polarity from (8). Here, the potential difference between the first voltage 8 and the discharge preventing voltage A may be smaller than the potential difference between the first voltage 8 and the discharge voltage B. FIG.

Since the discharge preventing voltage A of the second voltage 7 has the same polarity as that of the first voltage 8, repulsive force is generated between the ink and the discharged object 130 so that ink is not discharged. Since the discharge voltage B of the second voltage 7 has a different polarity from that of the first voltage 8, an attraction force may be generated between the ink and the discharged object 130 so that the ink may be discharged.

It is preferable that the potential difference between the discharge voltage B and the first voltage 8 is much larger than the potential difference between the discharge prevention voltage A and the first voltage 8.

The electrohydraulic inkjet device 100 according to the embodiment of the present invention has a small magnitude voltage having the same potential as the DC voltage applied to the object to be discharged 130 while the discharge head 120 or the nozzle 125 is moving. Is applied to the discharge head 120 / nozzle 125, it is possible to prevent the ink from being discharged while the discharge head 120 or the nozzle 125 is moving, and to prevent the ink from being discharged to an undesired point. It may be.

The control unit 170, when either the discharge head 120 or the discharged object 130 is moved, the potential A having the same polarity as the first voltage 8 of the second voltage 7 is discharge head It may be controlled to be applied to either the 120 or the object to be discharged (130). When the discharge pulse is not applied, the control unit 170 applies the same polarity to the discharge head 120 / nozzle 125 so as not to be discharged by the DC voltage, so that the repulsive force is generated, so that the discharge head 120 can be stably moved. . In this way, the voltage amplifier 160 is applied with a voltage of the same weakest polarity so that the discharge can be performed only at the position of the pulse B.

When only DC voltage is applied, when the pulse is not applied, it is not discharged and the shape of the meniscus should be maintained. However, if the DC voltage is made larger than an appropriate level or the distance between the discharge head 120 and the object to be discharged 130 such as the substrate is close, some drops of ink may be dropped even if the discharge pulse is not applied. In order to prevent such a problem, the electrohydraulic inkjet device 100 according to an embodiment of the present invention uses a method of slightly applying a voltage having the same polarity to the opposite side to which the DC voltage is applied. In the case of discharging, discharge is performed by applying a voltage of a different polarity. The discharge preventing voltage A of the second voltage 7 may be enough to be given a small size of about 2 to 3 (V). Therefore, it is not necessary to overload the voltage amplifier 160 or use a high voltage voltage amplifier.

On the other hand, in the case where the first voltage and the second voltage are both direct current voltages having the same polarity, discharge of ink droplets can be prevented even if the absolute value of the potential of the second voltage is smaller than the absolute value of the potential of the first voltage. For example, when the first voltage applied to the object to be discharged 130 is a DC voltage of 1 kV, the second voltage applied to the discharge head 110 / nozzle 125 is sufficient even if only a DC voltage of 5 to 10 V is sufficient. The discharge of drops can be prevented. As described above, when the weak DC voltage having the same polarity as the first voltage is set as the second voltage, the charged polarity and the polarity of the ink become the same voltage, so that the discharge is weakly performed.

FIG. 7 shows a flow chart of a method of controlling the device such that it is not discharged during movement of the discharge head 120. First, a step 1100 of supplying ink to the discharge head 120 by the purge / suction controller 110 is performed. After the ink is supplied, a step 1200 of separating the voltage applied to the discharge head 120 / the nozzle 125 by the controller 170 from the discharge object 120, such as a substrate, may be performed. have.

After separating the applied voltage, a step 1300 of applying two types of voltages having different potentials to the discharge head 120 / nozzle 125 and the to-be-exposed object 130 such as a substrate may be performed.

After determining whether the discharge head 120 / nozzle 125 or the to-be-exposed object 130, such as a substrate, is moved (1400), when moving, ink droplets are prevented only when the discharge voltage is prevented and the discharge voltage is applied during the movement. When discharged and a non-ejection voltage is applied, steps of applying two kinds of voltages having different waveforms to the discharge head 120 / nozzle 125 and the to-be-exposed object 130 such as a substrate so that ink droplets are not discharged (1500) ) May be performed.

While the discharge head 120 / nozzle 125 or the to-be-exposed object 130 such as the substrate is moving, the voltage having both positive and negative potentials is discharged from the discharge head 120 / nozzle 125 or the to-be-exposed object 130 such as the substrate. Step 1600 is applied to one and applying a DC voltage to the other. In step 1500, one kind of voltage waveform is a direct current voltage and the other kind of voltage waveform is a pulse voltage. In step 1600, the pulse voltage is a non-emission voltage having both the same potential as the direct current voltage and another potential and having the same potential as the direct current voltage. The absolute value is smaller than the absolute value of the discharge voltage having a potential different from that of the direct current voltage. As such, by applying a pulse voltage having both a potential having the same polarity as that of the DC voltage and a potential having a different polarity to the discharge head 120 / nozzle 125 or the discharged object 130 such as a substrate, ink droplets are discharged during movement. Can be prevented, and it is possible to accurately discharge only when a discharge pulse occurs, so that the accuracy of the printing pattern can be increased. 5 illustrates a case in which a DC voltage is applied to the object to be discharged 130 such as a substrate, and a pulse voltage having both positive and negative potentials is applied to the discharge head 120 / nozzle 125, and vice versa. Do.

When discharge is continuously performed, it is made to discharge using a DC voltage etc., and when a discharge is abruptly stopped, the voltage of the same polarity as a DC voltage may be applied.

In addition, when the discharge head 120 / nozzle 125 is moved, a method of discharging is not performed, and the effect of the distance between the nozzle 125 and the object to be discharged 130 does not reach the discharge or not, the electro-hydraulic ink jet It can be an important part of the device. When the electrohydraulic inkjet apparatus 100 is a three-axis stage, increasing the distance between the nozzle 125 and the discharged object 130 may prevent unwanted ejection. Because the power of static electricity is inversely proportional to the distance.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art, various modifications and variations are possible from these descriptions. Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

100,200: Electrohydrodynamic ink jet apparatus
110, 210: purge / suction controller 120, 220: discharge head
125, 225: nozzles 130, 230:
140,240: Power supply 150,250: Arbitrary waveform generator
160,260: voltage amplifier 170,270:

Claims (8)

A discharge head having at least one nozzle through which ink drops are discharged;
A protrusion opposed to the nozzle and on which ink droplets ejected from the nozzle are printed;
A power supply connected to the ejection head or the object to apply a first voltage;
An arbitrary waveform generator for generating a second voltage to be applied to the object or the discharge head;
A voltage amplifier connected to the arbitrary waveform generator for amplifying the second voltage and applying the second voltage amplified to the object or the discharge head; And
And a control unit connected to the power supply and the arbitrary waveform generator for controlling a state in which the first voltage or the second voltage is applied to the ejection head or the object,
The controller may control the first voltage and the second voltage to have the same polarity when the discharge head or the discharged object moves, or increase the distance between the discharge head and the discharged object. ,
The first voltage is a DC voltage, the second voltage is a DC voltage having the same polarity as the pulse voltage or the first voltage,
And the potential of the same polarity as the first voltage and a potential different from the first voltage when the second voltage is a pulse voltage.
The method of claim 1,
Wherein the control unit separates a voltage applied to the discharge head from a voltage applied to the discharge object, and when any one of the first voltage and the second voltage is applied to the discharge head, And controls the other one of the second voltages to be applied.
delete delete The method of claim 1,
When the second voltage is a pulse voltage, the absolute value of the potential having the same polarity as the first voltage is less than the absolute value of the potential having a polarity different from the first voltage, and the second voltage is a direct current voltage And the absolute value of the potential of the second voltage is smaller than the absolute value of the potential of the first voltage.
The method of claim 5,
The control unit is configured to apply a potential having the same polarity as the first voltage among the second voltages that are pulse voltages to either the discharge head or the discharged object when either the discharge head or the discharged object moves. An electrohydraulic inkjet device, characterized in that to control to.
The method of claim 1,
When the second voltage is a pulse voltage has a discharge prevention voltage and a discharge voltage in sequence, the discharge prevention voltage has the same polarity as the first voltage and the discharge voltage has a different polarity than the first voltage An electrohydraulic inkjet device.
The method of claim 7, wherein
And the potential difference between the first voltage and the discharge preventing voltage is smaller than the potential difference between the first voltage and the discharge voltage.

Images