KR102161906B1 - pressure controller for meniscus pressure of ink-jet nozzle - Google Patents

Abstract

An apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention includes: a supply pipe to which pressure is applied; A first conduit through which the internal pneumatic pressure of the reservoir in which the ink is accommodated is applied; A second pipe having one end connected to the first valve and the other end connected to the outside atmosphere; A first valve provided between the supply pipe and the first pipe and opening and closing the supply pipe, the first pipe and the second pipe; A first sensor measuring a first applied pressure applied to the first pipe; And when the absolute value of the first applied pressure measured by the first sensor exceeds the absolute value of the target pressure, the first applied pressure is increased by controlling the first valve to increase the opening rate of the second pipe. A control unit controlling the target pressure; Includes.

Description

Pressure controller for meniscus pressure of ink-jet nozzle

The present invention relates to a fine pressure control device of an inkjet nozzle, and to a fine pressure control device of an inkjet nozzle capable of precisely controlling the meniscus state of the inkjet nozzle by precisely controlling the internal air pressure of a reservoir containing ink. .

Ink-jet technology is a technology in which liquid ink is jetted through fine nozzles and fixed to paper. Inkjet technology has been generally used in non-impact printing apparatuses capable of obtaining desired characters, figures, or pictures by finely spraying ink onto paper or a printing medium.

Such inkjet technology is used not only in graphic printing devices, but also in liquid crystal display (LCD), organic light-emitting diodes (OLED), and semiconductor manufacturing processes. In particular, it is also used to form an organic thin film during the encapsulation process of forming a fine thin film during a semiconductor process or encapsulating the organic light emitting layer (EML) during an organic light emitting diode (OLED) manufacturing process. In addition, inkjets are also used in thin film encapsulation (TFE), which is an encapsulation layer of an organic light emitting layer, when manufacturing flexible OLEDs.

The inkjet nozzle provided in the inkjet head sprays fine droplets of several to tens of nanograms (ng) onto the substrate from individual nozzles to form a thin film having a thickness of several microns. Therefore, the discharge amount of ink must be precisely controlled to display or A thin film of the quality required in a semiconductor process can be manufactured.

In order to precisely control the discharge amount, a negative pressure is generally applied to the inkjet nozzle so that the tip of the ink is inserted into the nozzle, which is called a meniscus.

Since the state of the meniscus changes according to the internal pneumatic state of the reservoir connected to the inkjet head, the internal pneumatic pressure of the reservoir must be precisely controlled so that the state of the meniscus is maintained stably and the discharge amount is precisely controlled. Alternatively, it is possible to implement the thin film quality required in the semiconductor process.

1 is a schematic diagram of a system for controlling a meniscus (m) pressure of a general inkjet nozzle 4. Referring to FIG. 1, a reservoir 2 in which ink (i) is accommodated, an ink-jet head 3 to which ink (i) is supplied from the reservoir 2, and the ink-jet head 3 are provided at the ends of the substrate. It consists of an inkjet nozzle 4 for discharging ink (i), and a pressure control device (1) connected to the reservoir (2) to control the internal air pressure (O) of the reservoir (2).

As described above, the pressure control device 1 controls the internal pneumatic pressure O of the reservoir 2 to maintain a constant meniscus m state of the inkjet nozzle 4, and the pressure control device 1 When negative pressure is first applied to the reservoir (2) with ), the pressure in the pressure control device (1) rises rapidly. Thereafter, pressure hunting occurs while the on/off valves for pressure control operate on/off. If the valves are not well controlled, a problem in that the pressure hunting phenomenon is maintained for a long time may occur. In addition, even when a positive pressure is first applied to the reservoir 2 for the initial discharge of ink, pressure hunting and instability may occur due to this pressure difference.

In particular, in an environment in which a negative pressure of less than 0 to -10 kPa or more is applied as a relative pressure, when the pressure is controlled in units of 1 Pa to control the discharge amount of fine droplets of several to tens of nanometers, such pressure hunting and instability are caused by the reservoir (2 In some cases, the internal pneumatic pressure (O) of) is unstable, which causes a defect in discharging of the ink.

In addition, as the level of ink accommodated in the reservoir 2 gradually decreases, the pressure of the meniscus m is slightly changed due to the micro pressure change according to the change in the ink level, so that the volume and speed of the discharged droplets are changed from the set value. As it is changed, a collision error occurs on the substrate, causing product defects.

In addition, when a regulator is additionally installed in the reservoir 2 for precise control of pressure, when negative pressure is first applied, backflow occurs due to the pressure inside the reservoir 2, and the pressure of the regulator may be damaged.

Therefore, when pressure is first applied, pressure hunting is minimized, and the internal pneumatic pressure (O) of the reservoir (2) is precisely controlled without the need for a separate regulator to precisely maintain the pressure of the meniscus (m), and There is a need to develop a fine pressure control device for inkjet nozzles that can reduce manufacturing costs by simplifying.

An object to be solved by the present invention is to provide a fine pressure control device of an inkjet nozzle capable of precisely controlling the meniscus state of the inkjet nozzle by precisely controlling the internal air pressure of the reservoir containing the ink.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

The micro-pressure control apparatus of an inkjet nozzle including according to an embodiment of the present invention for solving the above problem includes: a supply pipe to which pressure is applied; A first conduit through which the internal pneumatic pressure of the reservoir in which the ink is accommodated is applied; A second pipe having one end connected to the first valve and the other end connected to the outside atmosphere; A first valve provided between the supply pipe and the first pipe and opening and closing the supply pipe, the first pipe and the second pipe; A first sensor measuring a first applied pressure applied to the first pipe; And when the absolute value of the first applied pressure measured by the first sensor exceeds the absolute value of the target pressure, the first applied pressure is increased by controlling the first valve to increase the opening rate of the second pipe. A control unit controlling the target pressure; Includes.

In addition, the first valve may be implemented as a proportional control valve.

In addition, the first valve may be implemented as a three-way valve.

In addition, the first valve may include an upper port connected to the supply pipe; A central port in communication with the upper port and connected to the first pipe; A lower port communicating with the central port and connected to the second pipe; A first seal provided between the upper port and the central port and opening and closing the supply pipe; And a second seal provided between the central port and the lower port to open and close the second pipe. It may include.

In addition, an adapter having a hole formed at an end of the second pipe may be further provided to allow the second pipe to communicate with the external atmosphere.

In addition, the first sensor may be provided at an end of the measuring pipe branched from the first pipe.

In addition, a third pipe connected to the reservoir; A backflow sensor provided between the third pipe and the reservoir; A fourth pipe connected to a drain tank for accommodating ink; And a third valve provided at a rear end of the first pipe and connecting the third pipe to one of the first pipe or the fourth pipe. It may further include.

In addition, the controller may control the third valve to connect the third pipe to the fourth pipe.

Details of other embodiments are included in the detailed description and drawings.

The micro-pressure control device of an inkjet nozzle according to an embodiment of the present invention minimizes the pressure hunting time when applying negative or positive pressure for the first time, stabilizes the pressure quickly, and precisely controls the internal air pressure of the reservoir without a separate regulator. The pressure of the varnish can be precisely maintained.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those of ordinary skill in the art from the description of the claims.

1 is a schematic diagram of a system for controlling a meniscus pressure of a general inkjet nozzle.
2 is a perspective view of an apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention.
3 is a bottom perspective view of an apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention.
4 is a cross-sectional view of an apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention.
5 is a schematic diagram of an apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention.
6 is a graph showing an operation section in which a first valve or a second valve actually operates according to an embodiment of the present invention.
7 is a graph showing that a fine pressure control device of an inkjet nozzle according to an embodiment of the present invention is controlled when a positive pressure is first applied to a supply pipe.
8 is a graph showing that the micro-pressure control device of the inkjet nozzle according to an embodiment of the present invention is controlled when a negative pressure is first applied to a supply pipe.
9 is a control flow chart of an apparatus for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention.
10 is a graph showing that the micro-pressure control apparatus of the inkjet nozzle according to an embodiment of the present invention is controlled when the target pressure is reset after a positive pressure is applied to the supply pipe.
11 is a graph showing that the micro-pressure control apparatus of the inkjet nozzle according to an embodiment of the present invention is controlled when the target pressure is reset after the negative pressure is applied to the supply pipe.
12 is a diagram illustrating an operation of controlling a third valve by a controller according to an embodiment of the present invention.
13 is a diagram illustrating an apparatus for controlling a fine pressure of an inkjet nozzle according to another embodiment of the present invention.
14 is a schematic diagram of an apparatus for controlling fine pressure of the ink jet nozzle shown in FIG. 13.
15 is an operation diagram of a first valve according to another embodiment of the present invention.
FIG. 16 is a graph showing that a fine pressure control device of an inkjet nozzle according to another embodiment of the present invention is controlled when a positive pressure is first applied to a supply pipe.
FIG. 17 is a graph showing that when a negative pressure is first applied to a supply pipe, a fine pressure control device of an inkjet nozzle according to another embodiment of the present invention is controlled.
18 is a control flowchart of an apparatus for controlling a fine pressure of an inkjet nozzle according to another embodiment of the present invention.
19 is a view showing an operation of controlling a third valve according to another embodiment of the present invention.
20 is a detailed operation diagram of the third valve shown in FIG. 19.

In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Even if the terms are the same, if the displayed parts are different, the reference numerals do not coincide.

In addition, terms to be described later are terms set in consideration of functions in the present invention, and since they may vary according to the intention or custom of operators such as experimenters and measurers, their definitions should be made based on the contents throughout this specification.

In the present specification, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals shown in each drawing indicate the same member.

Hereinafter, a structure of the fine pressure control device 1 of an inkjet nozzle according to an embodiment of the present invention will be described with reference to FIGS. 2 to 6, and the operation will be described below in FIG.

2 is a perspective view of an apparatus 1 for controlling fine pressure of an inkjet nozzle according to an embodiment of the present invention, and FIG. 3 is a perspective view of a bottom of the apparatus 1 for controlling fine pressure of an inkjet nozzle according to an exemplary embodiment of the present invention. 4 is a cross-sectional view of an apparatus 1 for controlling fine pressure of an inkjet nozzle according to an exemplary embodiment of the present invention, and FIG. 5 is a schematic diagram of an apparatus 1 for controlling fine pressure of an inkjet nozzle according to an exemplary embodiment of the present invention. 6 is a graph showing an operation section in which the first valve 30 or the second valve 40 actually operates according to an embodiment of the present invention.

1 to 6, the micro-pressure control device 1 of an inkjet nozzle according to an embodiment of the present invention is connected to a reservoir 2 accommodating ink. The reservoir 2 is connected to an inkjet head 3 provided with a plurality of inkjet nozzles 4 for discharging ink i to a substrate.

A part of the reservoir 2 is accommodated as ink i, and the remaining part forms an air layer. In this case, the internal pneumatic pressure (O) of the reservoir 2 is performed by the pressure of the air layer.

The micro-pressure control device 1 of the inkjet nozzle is connected to the reservoir 2 and controls the internal pneumatic pressure O of the reservoir 2. Here, the micro-pressure control device 1 of an inkjet nozzle according to an embodiment of the present invention includes a supply pipe 11 to which pressure is applied, and an internal pneumatic pressure O of the reservoir 2 in which ink is accommodated. 1 pipe 13, the first valve 30 provided between the supply pipe 11 and the first pipe 13, one end is connected to the first pipe 13, the other end to the second pipe 15 It includes a second valve 40 connected to the outside atmosphere.

The body forms the exterior. A pipe to which pressure is applied may be formed inside the body. 2 or less, it is shown that the body is divided into two parts and formed into a first body 10 and a second body 20, but may be formed as one body. Hereinafter, it will be described as being implemented with the first body 10 and the second body 20, but the embodiment is not limited thereto.

The supply pipe 11 is formed in the first body 10. The supply pipe 11 may extend into the first body 10. Hereinafter, all of the pipes including the supply pipe 11 will be described as being formed by penetrating all or part of the first body 10 or the second body 20.

A preset pressure is applied to the supply pipe 11. Hereinafter, the pressure will be described as a relative pressure with atmospheric pressure as a reference value (zero, 0). Here, the preset pressure may be a negative pressure or a positive pressure. When negative pressure is applied, the applied pressure may be applied in the range of less than 0 to -98.1 kPa, and when positive pressure is applied, the applied pressure may be applied in the range of more than 0 to 981 kPa, but embodiments are not limited thereto. .

The first valve 30 may be provided outside the body. The first valve 30 may be provided on the upper surface of the first body 10. The first valve 30 is connected to the supply pipe 11. The first valve 30 may be provided at the rear end of the supply pipe 11. The first valve 30 is connected to the first conduit 13 and connects the supply conduit 11 and the first conduit 13. In this case, the first valve 30 is provided between the supply pipe 11 and the first pipe 13.

The first conduit 13 is formed in the body. The internal pneumatic pressure (O) of the reservoir 2 in which ink is accommodated is applied to the first pipe line 13. The first conduit 13 may extend to a third valve 50 to be described later. When the body is formed of the first body 10 and the second body 20, the first conduit 13 may be formed to connect the first body 10 and the second body 20.

The first valve 30 opens and closes the supply pipe 11. The first valve 30 is controlled by the operation of the control unit 90. The first valve 30 may be implemented as a proportional valve capable of proportionally controlling the pressure or flow rate in a continuous or multi-stage manner by an electric signal from the controller 90. The proportional control valve can increase the pressure linearly by adjusting the opening rate of the valve through proportional control different from the on/off valve.

That is, when the on/off valve is operated on, the valve is momentarily switched from the fully closed state to the fully open state, so that pressure is rapidly applied to the internal pipeline. For example, when a negative pressure of -98.1 kPa is applied to the supply pipe 11 and the on/off valve is opened, a negative pressure of -98.1 kPa is instantaneously applied to the first pipe 13, and a pressure shock in the pipe is generated. I can.

On the other hand, when implemented with a proportional control valve as in the present invention, even when a negative pressure of -98.1 kPa is applied to the supply pipe 11, a negative pressure of -98.1 kPa is not immediately applied to the first pipe 13, and the valve is not applied. The opening rate of is adjusted so that a pressure with a much smaller pressure difference is applied. This proportional control valve can implement a resolution of 1Pa.

However, even if the operating voltage is applied as illustrated in FIG. 6, the proportional control valve may not operate at the initially applied voltage and may have a non-operation period T1 that operates after a predetermined time. For example, when the voltage to reach the target pressure set by the user is set to 5V, the proportional control valve does not open immediately according to the design value (L1) when the initial voltage is applied, and the non-operation section (T1) is After passing, it reaches the operation section T2 and opens relatively rapidly. Accordingly, when the proportional control valve is first operated, the pressure in the pipeline may increase relatively rapidly, as in the actual value L2.

When power is applied to the first valve 30, an on operation is performed. When the first valve 30 operates, the side of the supply pipe 11 is opened, so that the pressure applied to the supply pipe 11 may be applied to the first pipe 13. In this case, as described above, when pressure is first applied to the supply pipe 11, the pressure may increase rapidly. This will be described later.

The second valve 40 may be provided outside the body. The second valve 40 may be provided on the upper surface of the first body 10. The second valve 40 may be disposed at the rear end of the first valve 30.

One end of the second valve 40 is connected to the first pipe line 13. The other end of the second valve 40 is connected to the external atmosphere. The other end of the second valve 40 may be connected to the outside atmosphere through a second conduit 15 formed in the first body 10. In this case, the second pipe 15 may be formed on the first body 10 so as not to interfere with the first pipe 13 and to be connected to the outside atmosphere.

An adapter 70 may be provided at an end of the second conduit 15. In this case, the adapter 70 may be provided under the first body 10. A fine-sized hole h may be formed in the adapter 70. The hole (h) diameter may be formed to be 0.3 mm or less. The hole (h) allows the second pipe 15 to communicate with the outside atmosphere.

The second valve 40 opens and closes the second pipe 15. The second valve 40 is controlled by the operation of the control unit 90. The second valve 40 may also be implemented with the proportional control valve described above. Since the second valve 40 is the same as the first valve 30, a detailed description will be omitted.

When power is applied to the second valve 40, an on operation is performed. When the second valve 40 is operated, the side of the second pipe 15 is opened so that atmospheric pressure may be applied to the first pipe 13 through the second pipe 15. Atmospheric pressure is applied to the second conduit 15 through a fine-sized hole h, and the second valve 40 can precisely control the applied atmospheric pressure and apply it to the first conduit 13.

The first sensor 60 may be provided in the first conduit 13. The first sensor 60 may be disposed on the side of the first body 10 and may be provided to be introduced into the first conduit 13. In the case of an embodiment of the present invention, the first sensor 60 is described as being positioned between the first valve 30 and the second valve 40, but the embodiment is not limited thereto.

The first sensor 60 measures a first applied pressure applied to the first conduit 13. The first sensor 60 measures the first applied pressure of the first pipe 13 and transmits it to the control unit 90. The first sensor 60 may be implemented as a piezo sensor.

The controller 90 compares the first applied pressure measured by the first sensor 60 with a preset target pressure. The target pressure is defined as the pressure set by the user as a target value for the internal pneumatic pressure (O) of the reservoir (2).

When the first applied pressure measured by the first sensor 60 is different from the preset target pressure, the controller 90 opens the second valve 40. In this case, external atmospheric pressure connected to the second pipe 15 is applied to the first pipe 13. This will be described later.

The body according to the present invention may be provided with a third pipe 17, a fourth pipe 19, and a third valve 50. As described above, when the body is implemented with the first body 10 and the second body 20, the third pipe 17, the fourth pipe 19, the third valve ( 50) may be provided, but the embodiment is not limited thereto.

The third conduit 17 is connected to the reservoir 2 containing ink. In this case, the third conduit 17 is connected to the air layer in which the ink of the reservoir 2 is not accommodated. Accordingly, the internal pneumatic pressure O of the reservoir 2 is applied to the third conduit 17. Hereinafter, the applied pressure of the third pipe 17 will be described as being the same as the internal pneumatic pressure O of the reservoir 2.

The fourth pipe 19 is connected to the outside atmosphere. The diameter of the fourth pipe 19 may be formed in a fine size. External atmospheric pressure is applied to the fourth pipe 19. In addition, according to an embodiment, an adapter having a fine-sized hole may be provided in the fourth conduit 19.

The third valve 50 is provided on the body. The third valve 50 may be disposed on an upper surface of the second body 20 so that a part of the third valve 50 is inserted into the second body 20. The third valve 50 is provided at the rear end of the first pipe line 13.

The third valve 50 may be implemented as a 3-Way valve. The third valve 50 rises or falls according to a control signal from the controller 90 to connect the third pipe 17 to either the first pipe 13 or the fourth pipe 19.

The third valve 50 basically connects the first pipe 13 and the third pipe 17. In this case, the internal pneumatic pressure O of the reservoir 2 may be applied to the first conduit 13 along the third conduit 17. As the third pipe 17 is connected to the first pipe 13, the internal air pressure O of the reservoir 2 can be measured in the first pipe 13. It will be described later that the third valve 50 connects the third pipe 17 to the fourth pipe 19.

A fine hollow c may be formed under the second body 20 provided with the third valve 50. The fine hollow (c) is disposed in a straight line with the third valve (50). The fine hollow (c) is not connected to the third pipe (17) or the fourth pipe (19). The fine hollow (c) functions as an air vent so that the third valve 50 can move when the third valve 50 is operated in the vertical direction with respect to the second body 20.

A second sensor 80 may be provided at a rear end of the first conduit 13. The second sensor 80 may be disposed on the side of the second body 20 and may be provided to be introduced into the first conduit 13. The second sensor 80 measures the pressure applied to the rear end of the first pipe 13. The second sensor 80 may be implemented as a piezo sensor.

In this case, the second sensor 80 measures the second applied pressure applied to the rear end of the first conduit 13 separately from the first sensor 60. That is, when the third pipe 17 is connected to the first pipe 13, the second sensor 80 can measure the internal air pressure (O) of the reservoir 2 applied from the third pipe 17. have. At this time, the second applied pressure sensed by the second sensor 80 may be the same when the first sensor 60 and the second sensor 80 are as close as possible within the first conduit 13, and the first sensor When the 60 and the second sensor 80 are spaced apart as much as possible within the first pipe 13, there may be a slight difference. The second sensor 80 measures the second applied pressure of the first pipe 13 and transmits it to the control unit 90.

According to an embodiment, when the second sensor 80 is not provided, the first sensor 60 may replace the function of the second sensor 80. In this case, the pressure at the front and rear ends of the first sensor 60 may be slightly different depending on the position of the first sensor 60, but the pressure applied to the first conduit 13 is described as being the same applied pressure. do.

Depending on the embodiment, the second sensor 80 may be used as an auxiliary sensor of the first sensor 60. That is, when both the first sensor 60 and the second sensor 80 are provided, the second sensor 80 may function as a sensor that measures the first applied pressure when the first sensor 60 fails. .

Hereinafter, the operation of the micro-pressure control apparatus 1 of an inkjet nozzle according to an embodiment of the present invention will be described with reference to FIGS. 7 to 9.

7 is a graph showing that the fine pressure control device 1 of the ink jet nozzle according to an embodiment of the present invention is controlled when positive pressure is first applied to the supply pipe 11, and FIG. 8 is It is a graph showing that the micro pressure control device 1 of an inkjet nozzle according to an embodiment of the present invention is controlled when a negative pressure is first applied, and FIG. 9 is a micro pressure control device of an ink jet nozzle according to an embodiment of the present invention. Is a control flow chart.

7 to 9, the control unit 90 of the fine pressure control device 1 of the inkjet nozzle according to an embodiment of the present invention, the absolute value of the first applied pressure measured by the first sensor 60 When the absolute value of the target pressure is exceeded, the second valve 40 is opened so that external atmospheric pressure is applied to the first pipe line 13, and the first applied pressure is controlled to the target pressure.

First, positive pressure or negative pressure is applied to the supply pipe 11 as shown in FIG. 7 or 8. The third valve 50 connects the first pipe 13 and the third pipe 17 so that the internal pneumatic pressure O of the reservoir 2 is applied to the first pipe 13. When pressure is applied to the supply pipe 11, the first valve 30 is powered to perform an on operation.

In this case, as described above, when pressure is first applied to the supply pipe 11, the pressure rises or falls rapidly, and a pressure increase section P1 appears as shown in FIG. 7 or 8. In the case of FIG. 7, when a positive pressure is applied, the first applied pressure rises rapidly (in the + direction), and in the case of FIG. 8, when a negative pressure is applied, the first applied pressure drops rapidly (in the-direction).

The first sensor 60 measures a first applied pressure applied to the first conduit 13. The first sensor 60 measures the first applied pressure of the first pipe 13 and transmits it to the control unit 90.

When positive pressure is supplied to the supply pipe 11 as shown in FIG. 7, the control unit 90 compares the preset target pressure with the magnitude of the first applied pressure. When the first applied pressure is less than the target pressure, the control unit 90 opens the first valve 30 in a proportional control manner so that the first applied pressure reaches the target pressure.

Conversely, when the first applied pressure exceeds the target pressure (the absolute value of the first applied pressure exceeds the absolute value of the target pressure), the controller 90 opens the second valve 40. When the second valve 40 is turned on and opened, external atmospheric pressure is applied to the first pipe line 13.

On the other hand, when the negative pressure is supplied to the supply pipe 11 as shown in FIG. 8, the control unit 90 compares the preset target pressure and the magnitude of the first applied pressure. When the first applied pressure exceeds the target pressure (when the absolute value of the first applied pressure is less than the absolute value of the target pressure), the control unit 90 opens the first valve 30 in a proportional control manner to Make the applied pressure reach the target pressure.

Conversely, if the first applied pressure is less than the target pressure (the absolute value of the first applied pressure exceeds the absolute value of the target pressure), the control unit 90 opens the second valve 40. When the second valve 40 is turned on and opened, external atmospheric pressure is applied to the first pipe line 13.

Thereafter, when positive or negative pressure is supplied to the supply pipe 11 and the absolute value of the first applied pressure sensed by the first sensor 60 while the second valve 40 is operating is less than the absolute value of the target pressure, the first One valve 30 may be further opened. At this time, the first valve 30 and the second valve 40 are slightly opened to each other, so that the first applied pressure increases and decreases based on the target pressure, and a pressure hunting phenomenon may occur. 7 and 8 illustrate the pressure hunting section P2 accordingly.

In this case, the second valve 40 is finely controlled again in a proportional control method. Atmospheric pressure is proportionally controlled through the hole h of the adapter 70 connected to the second valve 40 and applied to the first pipe 13 along the second pipe 15.

Accordingly, pressure compensation is performed in the first conduit 13 to control the first applied pressure. In the case of FIG. 7 to which positive pressure is applied, the atmospheric pressure applied in the first pipe line 13 by the second valve 40 lowers the first applied pressure (negative compensation), and in the case of FIG. 8 to which the negative pressure is applied, the second The atmospheric pressure applied in the first pipe line 13 by the valve 40 increases the first applied pressure (positive compensation). When the first applied pressure is controlled to be equal to the target pressure, the controller 90 may close the second valve 40 to cut off the external atmospheric pressure.

Finally, when the first applied pressure is controlled to the target pressure and enters the pressure stabilization section (P3), the internal air pressure (O) of the reservoir (2) is constantly controlled, so the inkjet nozzle (4) connected to the reservoir (2) The meniscus (m) state of is stabilized.

According to the embodiment, when the second sensor 80 is further provided, the control unit 90 may use the second applied pressure measured by the second sensor 80. In this case, the controller 90 may compare the average value of the first applied pressure and the second applied pressure with the target pressure, but the embodiment is not limited thereto.

In the case of FIGS. 7 and 8, a graph showing these results is shown. A pressure increase section P1 after a positive or negative pressure is applied to the supply pipe 11, a pressure hunting section P2 in which the first applied pressure is controlled, and a pressure stabilization section P3 are shown.

The duration of each section is different depending on the embodiment, but the pressure increase section (P1) was controlled within 1 second and the pressure hunting section (P2) within 3 seconds in the range of 1 to 10 bar target pressure. In addition, when the target pressure is 0 to 1 bar, the pressure increase section (P1) is controlled within 0.5 seconds, and the pressure hunting section (P2) is controlled within 1 second, and it is shown that pressure hunting is quickly controlled.

Thereafter, in the pressure stabilization section P3, the first applied pressure is controlled equal to the target pressure, and the pressure can be controlled in units of 1 Pa. In the pressure stabilization section (P3), since the first applied pressure applied to the first pipe (13) is the same as the internal air pressure (O) of the reservoir (2), the internal air pressure of the reservoir (2) is the target pressure desired by the user. Since (O) can be controlled in units of 1Pa, the meniscus (m) state can be precisely controlled.

As described above, the micropressure control device 1 of an inkjet nozzle according to an embodiment of the present invention minimizes the pressure hunting time when applying negative or positive pressure for the first time, and quickly stabilizes the pressure so that the reservoir 2 can be controlled without a separate regulator. By precisely controlling the internal pneumatic pressure (O), the pressure of the meniscus (m) is precisely maintained, and the structure is simple to reduce the manufacturing cost.

Hereinafter, another operation of the fine pressure control device 1 of an inkjet nozzle according to an embodiment of the present invention will be described with reference to FIGS. 10 to 11.

10 is a graph showing that the fine pressure control device 1 of the inkjet nozzle according to an embodiment of the present invention is controlled when the target pressure is reset after a positive pressure is applied to the supply pipe 11, and FIG. 11 is a supply pipe A graph showing that the fine pressure control device 1 of the inkjet nozzle according to an embodiment of the present invention is controlled when the target pressure is reset after the negative pressure is applied to the furnace 11.

Referring to FIG. 10 or 11, first, the target pressure for the internal pneumatic pressure O of the reservoir 2 is reset by the user. Here, the pressure is a relative pressure as described above. The control unit 90 controls the first valve 30 so that the first applied pressure reaches the target pressure. Accordingly, positive pressure or negative pressure is further applied to the supply pipe 11.

When positive or negative pressure is applied to the supply pipe 11, the controller 90 controls the opening rate of the first valve 30 so that the first applied pressure matches the reset target pressure.

First, when the absolute value of the first applied pressure changed as described above is less than the absolute value of the target pressure, the control unit 90 opens the first valve 30 in a proportional control method so that the first applied pressure reaches the target pressure. Do it.

Conversely, when the absolute value of the first applied pressure changed as shown in FIG. 10 or 11 exceeds the absolute value of the target pressure, the controller 90 opens the second valve 40. The controller 90 controls the second valve 40 in a proportional control method to control the first applied pressure to the target pressure.

10 to 11 show the results of controlling the first applied pressure to the target pressure. When controlling the first valve 30 and the second valve 40 in multiple stages, each pressure is changed to a 1 kPa section, and the pressure holding time is set to 10 sec.

In the case of FIG. 10, after the target pressure is reset from positive pressure 1 kPa to 2 kPa, process variables, equipment operating conditions change, ink filling of the reservoir 2, inkjet nozzles are temporarily clogged, and various positive pressures are applied to resolve this. When the first valve 30 is opened with an over positive pressure of 4 kPa for a period of 30 sec due to a variable, the control unit 90 controls the second valve 40. In this case, the second valve 40 is opened for a period of 50 sec, and the atmospheric pressure is applied to the first pipe line 13 to drop the first applied pressure to control the reset target pressure of 2 kPa.

Likewise, in the case of FIG. 11, when the target pressure is reset from -1 kPa to -3 kPa and then the first valve 30 is opened with an over negative pressure of -5 kP until the 40 sec period, the controller 90 Controls the 2 valve 40. In this case, the second valve 40 is opened for a period of 60 sec, and the atmospheric pressure is applied to the first pipe line 13 to increase the first applied pressure, thereby controlling the reset target pressure to -3 kPa.

12 is a diagram illustrating an operation of controlling the third valve 50 by the control unit 90 according to an embodiment of the present invention.

Referring to FIG. 12, the third valve 50 may selectively open and close the first pipe 13 or the fourth pipe 19 according to a control signal from the controller 90. That is, the third valve 50 rises or falls according to the control signal of the control unit 90 to connect the third pipe 17 to either the first pipe 13 or the fourth pipe 19.

First, the third valve 50 connects the third pipe 17 to the first pipe 13 so that the internal pneumatic pressure O of the reservoir 2 is applied to the first pipe 13. In this case, as described above, the first applied pressure of the first pipe 13 is controlled so that the internal pneumatic pressure O of the reservoir 2 connected thereto is controlled, and finally the pressure of the meniscus m is controlled. do.

On the other hand, there is a case where the internal pneumatic pressure O of the reservoir 2 is changed due to a process variable or a change in the operation of the equipment or ink filling of the reservoir 2. In this case, the first applied pressure of the first pipe 13 may fluctuate rapidly.

At this time, when the second sensor 80 is provided at the rear end of the first conduit 13, or the first sensor 60 is provided at the rear end of the first conduit 13 without the second sensor 80, the first A pressure shock may occur on the sensor 60 or the second sensor 80. That is, a pressure shock occurs due to a pressure difference between the first applied pressure of the first pipe 13 and the internal pneumatic pressure O of the reservoir 2, and the first sensor 60 or the second sensor 80 Since it is implemented with a piezo sensor, physical damage may occur due to pressure shock.

At this time, the control unit 90 controls the third valve 50 to connect the third pipe 17 to the fourth pipe 19 connected to the external atmosphere. In this case, the first pipe 13 is closed by the third valve 50, and the reservoir 2 communicates with the external atmosphere along the third pipe 17 and the fourth pipe 19, Atmospheric pressure is applied to the internal pneumatic pressure (O) of (2). When the third valve 50 operates and connects the third pipe 17 to the fourth pipe 19, the fine hollow (c) functions as an air vent so that the third valve 50 can move. do.

According to an embodiment, when the internal pneumatic pressure (O) of the reservoir 2 is in an over-positive pressure state above atmospheric pressure, when the third valve 50 is controlled so that the third pipe 17 is connected to the fourth pipe 19, The internal pneumatic pressure (O) of the reservoir 2 is purged in the direction b of FIG. 12 to relieve the overpressure state.

In this case, a pneumatic sensor 5 that measures the internal pneumatic pressure O of the reservoir 2 and transmits it to the controller 90 may be provided inside the reservoir 2. The control unit 90 compares the internal pneumatic pressure O of the reservoir 2 measured by the pneumatic sensor 5 with the second applied pressure measured by the second sensor 80, and when the occurrence of a pressure shock is expected, 3, the valve 50 is controlled to connect the third pipe 17 to the fourth pipe 19.

Conversely, according to the embodiment, when the internal pneumatic pressure O of the reservoir 2 is in an excessive negative pressure state, when the third valve 50 is controlled so that the third pipe 17 is connected to the fourth pipe 19, In the direction a of FIG. 12, the internal pneumatic pressure O of the reservoir 2 is compensated by atmospheric pressure, so that the over-negative pressure state can be eliminated.

13 is a view showing a micro pressure control apparatus of an ink jet nozzle according to another embodiment of the present invention, FIG. 14 is a schematic diagram of a micro pressure control apparatus of the ink jet nozzle shown in FIG. 13, and FIG. 15 is It is an operation diagram of the first valve according to another embodiment.

Hereinafter, an apparatus for controlling a fine pressure of an inkjet nozzle according to another embodiment of the present invention will be described with reference to FIGS. 13 to 20. Detailed description of the same components among the above-described components will be omitted, and the components having differences will be mainly described.

13 to 15, the inkjet nozzle micropressure control apparatus according to another embodiment of the present invention includes a supply pipe 11 to which pressure is applied, and an internal pneumatic pressure of a reservoir 2 in which ink is accommodated. The first pipe 13, the second pipe 15 having one end connected to the first valve 31 and the other end connected to the outside atmosphere, provided between the supply pipe 11 and the first pipe 13, and the supply pipe The first valve 31 for opening and closing the furnace 11, the first pipe 13 and the second pipe 15, a first sensor 60 measuring a first applied pressure applied to the first pipe 13 , And when the absolute value of the first applied pressure measured by the first sensor 60 exceeds the absolute value of the target pressure, the first valve 31 is controlled to increase the opening rate of the second pipe 15 It includes a control unit 90 for controlling one applied pressure to the target pressure.

The body 100 forms the exterior. In another embodiment of the present invention, the body 100 is described as being integrally formed, but the embodiment is not limited thereto.

The second pipe 15 is formed in the body 100. One end of the second pipe 15 is connected to the first valve 31. In this case, as will be described later, the first valve 31 may open and close the second conduit 15. The other end of the second pipe 15 is connected to the outside atmosphere. In addition, as described in the embodiment of the present invention, the second conduit 15 is formed so as not to interfere with the first conduit 13.

An adapter 70 may be provided at an end of the second conduit 15. In this case, the adapter 70 may be provided on the lower side of the body 100. A fine-sized hole h may be formed in the adapter 70. The hole (h) diameter may be formed to be 0.3 mm or less. The hole (h) allows the second pipe 15 to communicate with the outside atmosphere.

The first valve 31 is provided between the supply pipe 11 and the first pipe 13. As described above, the first valve 31 may be implemented as a proportional control valve.

The first valve 31 may open and close the supply pipe 11, the first pipe 13, and the second pipe 15. In this case, the first valve 31 may be implemented as a 3-Way valve. The first valve 31 may open/close at least one of the supply pipe 11, the first pipe 13, and the second pipe 15 according to a control signal from the controller 90.

The first valve 31 may basically connect the supply pipe 11 and the first pipe 13. In this case, the second conduit 15 is closed. In addition, the first valve 31 may connect the first pipe 13 and the second pipe 15. In this case, the supply pipe 11 is closed.

The first valve 31 may not open or close all of each pipe, but may partially open or close each pipe. In this case, the degree to which the supply pipe 11, the first pipe 13, and the second pipe 15 are opened is defined as an open rate.

The first valve 31 may linearly increase or decrease the opening rate of the supply pipe 11, the first pipe 13, and the second pipe 15. That is, when the first valve 31 is implemented as a proportional control valve, the pressure applied to the upper port 330, which will be described later, can be linearly increased or decreased by adjusting the opening rate of the supply pipe 11 by proportional control. I can. Likewise, the first valve 31 may adjust the opening rate of the first pipe 13 and the second pipe 15 by proportional control.

Here, the first valve 31 according to another embodiment of the present invention includes a valve body 310 forming an external appearance, and a shaft 320 provided to move up and down on the valve body 310.

The valve body 310 forms an exterior. The valve body 310 may be provided to be exposed to the outside of the body 100. A control device for controlling the first valve 31 may be provided in the valve body 310.

The shaft 320 is raised and lowered by the valve body 310. The shaft 320 is raised and lowered based on the valve body 310 according to a control signal from the control unit 90. Here, as the first valve 31 is implemented as a proportional control valve, the displacement of the shaft 320 that is raised or lowered can be finely controlled. That is, the valve body 310 can raise or lower the shaft 320 by a predetermined displacement according to a control signal from the control unit 90, so that the displacement of the shaft 320 is finely controlled.

Here, the first valve 31 according to another embodiment of the present invention has an upper port 330 connected to the supply pipe 11, a central part communicated with the upper port 330 and connected to the first pipe 13 The port 340, the lower port 350 communicated with the central port 340 and connected to the second conduit 15, is provided between the upper port 330 and the central port 340, and provides a supply conduit 11 It includes a first seal 360 that opens and closes, and a second seal 370 that is provided between the middle port 340 and the lower port 350 and opens and closes the second conduit 15.

The upper port 330 is provided on the shaft 320. The upper port 330 may be connected to the supply pipe 11. The upper port 330 is raised and lowered together with the shaft 320 when the shaft 320 is raised or lowered. Hereinafter, the upper port 330, the middle port 340, and the lower port 350 will be described as being raised and lowered together with the shaft 320.

The middle port 340 is provided in the middle of the shaft 320. The middle port 340 is provided in communication with the upper port 330. The central port 340 may be connected to the first conduit 13. In this case, the negative or positive pressure applied to the supply pipe 11 may be applied to the central port 340 along the upper port 330, and finally applied to the first pipe 13.

The lower port 350 is provided under the shaft 320. The lower port 350 is provided to communicate with the central port 340. The lower port 350 may be connected to the second conduit 15. In this case, the atmospheric pressure applied to the second conduit 15 may be applied to the central port 340 along the lower port 350 and finally applied to the first conduit 13.

The first sealing 360 is provided between the upper port 330 and the middle port 340. The first sealing 360 is raised and lowered together with the shaft 320 when the shaft 320 is raised or lowered. In this case, the first sealing 360 may be raised or lowered to open and close the supply pipe 11.

One or more through holes 361 penetrating the first sealing 360 are formed in the first sealing 360. The through hole 361 communicates the upper port 330 and the central port 340 so that the pressure applied to the upper port 330 is applied to the central port 340.

In this case, the first sealing 360 may linearly increase or decrease the opening rate of the supply pipe 11. That is, the opening rate of the supply pipe 11 is increased or decreased according to the ratio of the first sealing 360 to shield the open end of the supply pipe 11, and the first valve 31 is implemented as a proportional control valve. Accordingly, the control unit 90 may finely control the displacement of the shaft 320 so that the first sealing 360 may finely increase or decrease the opening rate of the supply pipe 11. In this case, the first sealing 360 may linearly and finely increase or decrease the pressure applied to the supply pipe 11.

The second sealing 370 is provided between the middle port 340 and the lower port 350. Like the first seal 360, the second seal 370 moves up and down together with the shaft 320, and may open and close the second conduit 15. In this case, the second sealing 370 may linearly increase or decrease the opening rate of the second conduit 15, similar to the first sealing 360. In this case, the second sealing 370 may linearly and finely increase or decrease the pressure applied to the second pipe 15 by atmospheric pressure.

One or more through holes 371 penetrating through the second sealing 370 are formed in the second sealing 370. The through hole 371 communicates the middle port 340 and the lower port 350 so that the pressure applied to the middle port 340 is applied to the lower port 350.

When the second pipe 15 is completely closed by the second sealing 370 as shown in (a) of FIG. 15, the supply pipe 11 and the first pipe 13 may be completely open and communicate with each other. In addition, when the supply pipe 11 is completely closed by the first sealing 360 as shown in (b) of FIG. 15, the first pipe 13 and the second pipe 15 are completely open to communicate with each other. have.

In addition, as shown in (c) of FIG. 15, when the supply pipe 11 is partially opened by the first sealing 360, the second sealing 370 partially opens the second pipe 15 so that the supply pipe 11 ), the first pipe 13 and the second pipe 15 may be in communication with each other.

Here, referring to Figure 15 (c), the opening rate of the supply pipe 11 described above is completely compared to the remaining opening amount after the end (A) of the supply pipe 11 is partially shielded by the first sealing 360 It is a ratio of the opening amount, and the opening rate of the second pipe line 15 is the ratio of the total opening amount to the remaining open amount after the end B of the second pipe line 15 is partially shielded by the second sealing 370.

In this case, a pressure applied to the supply pipe 11 and a pressure applied through the second pipe 15 may be simultaneously applied to the first pipe line 13. In this case, the sum of the pressures applied through the supply pipe 11 and the second pipe 15 may be applied to the first pipe 13. The summation value accordingly may be implemented with the first applied pressure.

A sealing seal 380 may be provided at the lowermost portion of the shaft 320. A through hole is not formed in the hermetic sealing 380 and shields the lower port 350 from the outside.

A fine hollow c1 may be formed under the body 100 provided with the first valve 31. The fine hollow (c1) is disposed in a straight line with the first valve (31). The fine hollow (c1) is not connected to the supply pipe 11, the first pipe 13 and the second pipe 15. The fine hollow (c1) functions as an air vent so that the sealing seal 380 can move along the shaft 320 when the shaft 320 moves up and down.

The first sensor 60 measures the first applied pressure applied to the first pipe 13 as described above. The first sensor 60 may be provided on the body 100. The first sensor 60 according to another embodiment of the present invention may be provided at an end of the measuring pipe 14 branched from the first pipe 13. At this time, the measurement pipe 14 may be formed by branching from the first pipe 13 into a T shape. As the first sensor 60 is provided at the end of the measurement pipe 14, it is possible to easily replace the first sensor 60 in case of failure.

The applied pressure in the measurement pipe 14 may be the same as the first applied pressure. Hereinafter, it will be described that the applied pressure in the measurement pipe 14 is implemented as the first applied pressure.

The controller 90 compares the first applied pressure measured by the first sensor 60 with a preset target pressure. The target pressure is defined as the pressure set by the user as a target value for the internal pneumatic pressure (O) of the reservoir (2).

The controller 90 controls the first valve 31 when the first applied pressure measured by the first sensor 60 is different from the preset target pressure. This will be described later.

On the other hand, the body 100 according to another embodiment of the present invention may be provided with a third pipe 17, a fourth pipe 19, and a third valve 51.

The third conduit 17 is connected to the reservoir 2 containing ink. In this case, the third conduit 17 is connected to the air layer in which the ink of the reservoir 2 is not accommodated. Accordingly, the internal pneumatic pressure O of the reservoir 2 is applied to the third conduit 17. Hereinafter, the applied pressure of the third pipe 17 will be described as being the same as the internal pneumatic pressure O of the reservoir 2.

According to an exemplary embodiment, ink inside the reservoir 2 may flow backward through the third conduit 17. That is, when the first applied pressure is applied as a negative pressure and the reservoir 2 is filled with ink, the ink inside the reservoir 2 may be sucked through the third pipe 17 and some of the ink may flow backward. have. This will be described later.

A backflow detection sensor S may be provided between the reservoir 2 and the third pipe 17. When the ink inside the reservoir 2 flows back through the third pipe 17, the backflow sensor S detects the presence of ink and transmits it to the controller 90.

The fourth pipe 19 may be connected to the drain tank T. The drain tank T functions to receive the ink flowing back from the reservoir 2.

The third valve 51 may be provided on the body 100. The third valve 51 may be provided at the rear end of the first conduit 13.

The third valve 51 may be implemented as a 3-Way valve. The third valve 51 ascends or descends according to a control signal from the controller 90 to connect the third pipe 17 to either the first pipe 13 or the fourth pipe 19.

The third valve 51 basically connects the first pipe 13 and the third pipe 17. In this case, the internal pneumatic pressure O of the reservoir 2 may be applied to the first conduit 13 along the third conduit 17. As the third pipe 17 is connected to the first pipe 13, the internal air pressure O of the reservoir 2 can be measured in the first pipe 13. The third valve 51 connecting the third pipe 17 to the fourth pipe 19 will be described later.

A fine hollow c2 may be formed in the lower portion of the body 100 provided with the third valve 51. The fine hollow (c2) is disposed in a straight line with the third valve (51). The fine hollow (c2) is not connected to the third pipe (17) or the fourth pipe (19). The fine hollow c2 functions as an air vent so that the third valve 51 can move when the third valve 51 is operated in the vertical direction with respect to the body 100.

Hereinafter, an operation of an apparatus for controlling a fine pressure of an inkjet nozzle according to another embodiment of the present invention will be described with reference to FIGS. 16 to 18.

16 is a graph showing that the fine pressure control device 1 of the inkjet nozzle according to another embodiment of the present invention is controlled when positive pressure is first applied to the supply pipe 11, and FIG. 17 is a supply pipe 11 It is a graph showing that the micro pressure control device 1 of an inkjet nozzle according to another embodiment of the present invention is controlled when negative pressure is first applied to, and FIG. 18 is This is the control flow chart of the pressure control device.

16 to 18, the control unit 90 of the micro-pressure control device 1 of the inkjet nozzle according to another embodiment of the present invention is the absolute value of the first applied pressure measured by the first sensor 60. When the value exceeds the absolute value of the target pressure, the first valve 31 is controlled to increase the opening rate of the second pipe 15 so that external atmospheric pressure is additionally applied to the first pipe 1 The applied pressure is controlled to the target pressure.

First, positive pressure or negative pressure is applied to the supply pipe 11 as shown in FIG. 16 or 17. The third valve 51 connects the first pipe 13 and the third pipe 17 so that the internal pneumatic pressure O of the reservoir 2 is applied to the first pipe 13. When pressure is applied to the supply pipe 11, the first valve 31 is powered to perform an ON operation. Accordingly, the first valve 31 is operated so that the supply pipe 11 is connected to the first pipe 13.

In this case, as described above, when pressure is first applied to the supply pipe 11, the pressure rises or falls rapidly, and a pressure increase section P1 appears as shown in FIG. 16 or 17. In the case of FIG. 16, when a positive pressure is applied, the first applied pressure rises rapidly (in the + direction), and in the case of FIG. 17, when a negative pressure is applied, the first applied pressure drops rapidly (in the-direction).

The first sensor 60 measures a first applied pressure applied to the first conduit 13. The first sensor 60 measures the first applied pressure of the first pipe 13 and transmits it to the control unit 90.

When positive pressure is supplied to the supply pipe 11 as shown in FIG. 16, the controller 90 compares the preset target pressure with the magnitude of the first applied pressure. When the first applied pressure is less than the target pressure, the control unit 90 opens the first valve 31 in a proportional control manner so that the first applied pressure reaches the target pressure.

Conversely, when the first applied pressure exceeds the target pressure (the absolute value of the first applied pressure exceeds the absolute value of the target pressure), the controller 90 controls the first valve 31 to control the second pipe 15 Increase the opening rate of Accordingly, external atmospheric pressure is applied to the first conduit 13.

On the other hand, when the negative pressure is supplied to the supply pipe 11 as shown in FIG. 17, the control unit 90 compares the preset target pressure and the magnitude of the first applied pressure. When the first applied pressure exceeds the target pressure (when the absolute value of the first applied pressure is less than the absolute value of the target pressure), the control unit 90 opens the first valve 31 in a proportional control manner to Make the applied pressure reach the target pressure.

Conversely, when the first applied pressure is less than the target pressure (the absolute value of the first applied pressure exceeds the absolute value of the target pressure), the control unit 90 controls the first valve 31 to control the second pipe line 15. Increase the opening rate. Accordingly, external atmospheric pressure is applied to the first conduit 13.

Thereafter, when the second pipe 15 is opened and the absolute value of the first applied pressure sensed by the first sensor 60 becomes less than the absolute value of the target pressure, the controller 90 returns to the supply pipe. The first valve 31 may be controlled to increase the opening rate of the furnace 11. In this case, the valve body 310 may control the first sealing 360 to increase the opening rate of the supply pipe 11 by raising and lowering the shaft 320.

At this time, when the absolute value of the first applied pressure sensed by the first sensor 60 exceeds the absolute value of the target pressure, the control unit 90 again increases the opening rate of the second conduit 15. (31) can be controlled. Likewise, the valve body 310 may control the second sealing 370 to increase the opening rate of the second conduit 15 by raising and lowering the shaft 320.

In this case, as the opening rate of the supply pipe 11 and the opening rate of the second pipe 15 are changed, a pressure hunting phenomenon in which the first applied pressure increases and decreases based on the target pressure may occur. . At this time, the lifting and lowering operation of the shaft 320 is repeated, so that the amount of displacement of the shaft 320 may be finely controlled.

16 and 17 illustrate the pressure hunting section P2 accordingly. In the case of FIG. 16, when positive pressure is supplied, excessive pressure (over positive pressure) and insufficient pressure are repeated based on the target pressure. Similarly, in the case of FIG. 17, when negative pressure is supplied, excessive pressure (over-negative pressure) and insufficient pressure are repeated based on the target pressure.

Thereafter, the opening rate of the second pipe 15 is finely controlled again in a proportional control method. That is, the control unit 90 controls the opening rate of the second conduit 15, and the atmospheric pressure is proportionally controlled through the fine-sized hole h of the adapter 70 connected to the second conduit 15. Follow (15) to be applied to the first pipe line (13).

Accordingly, pressure compensation is performed in the first conduit 13 to control the first applied pressure. In the case of Fig. 16 where the positive pressure is applied, the atmospheric pressure applied in the first pipe 13 by the second pipe 15 lowers the first applied pressure (negative compensation), and in the case of Fig. 17 where the negative pressure is applied, the second The atmospheric pressure applied in the first pipe 13 by the pipe 15 increases the first applied pressure (positive compensation). When the first applied pressure is controlled to be equal to the target pressure, the controller 90 may maintain a constant opening rate of the second pipe 15.

Finally, when the first applied pressure is controlled to the target pressure and enters the pressure stabilization section (P3), the internal air pressure (O) of the reservoir (2) is constantly controlled, so the inkjet nozzle (4) connected to the reservoir (2) The meniscus (m) state of is stabilized.

In the case of FIGS. 16 and 17, graphs showing these results are shown. A pressure increase section P1 after a positive or negative pressure is applied to the supply pipe 11, a pressure hunting section P2 in which the first applied pressure is controlled, and a pressure stabilization section P3 are shown.

The duration of each section is different depending on the embodiment, but the pressure increase section (P1) was controlled within 1 second and the pressure hunting section (P2) within 3 seconds in the range of 1 to 10 bar target pressure. In addition, when the target pressure is 0 to 1 bar, the pressure increase section (P1) is controlled within 0.5 seconds, and the pressure hunting section (P2) is controlled within 1 second, and it is shown that pressure hunting is quickly controlled.

Thereafter, in the pressure stabilization section P3, the first applied pressure is controlled equal to the target pressure, and the pressure can be controlled in units of 1 Pa. In the pressure stabilization section (P3), since the first applied pressure applied to the first pipe (13) is the same as the internal air pressure (O) of the reservoir (2), the internal air pressure of the reservoir (2) is the target pressure desired by the user. Since (O) can be controlled in units of 1Pa, the meniscus (m) state can be precisely controlled.

As described above, the micropressure control device 1 of an inkjet nozzle according to an embodiment of the present invention minimizes the pressure hunting time when applying negative or positive pressure for the first time, and quickly stabilizes the pressure so that the reservoir 2 can be controlled without a separate regulator. By precisely controlling the internal pneumatic pressure (O), the pressure of the meniscus (m) is precisely maintained, and the structure is simple to reduce the manufacturing cost.

FIG. 19 is a diagram illustrating an operation of the control unit 90 controlling the third valve 51 according to another embodiment of the present invention, and FIG. 20 is a detailed operation of the third valve 51 shown in FIG. 19 Is also.

19 and 20, the third valve 51 may selectively open and close the first pipe 13 or the fourth pipe 19 according to a control signal from the controller 90. That is, the third valve 51 is raised or lowered according to the control signal of the control unit 90 to connect the third pipe 17 to either the first pipe 13 or the fourth pipe 19.

First, as shown in (a) of FIG. 20, the third valve 51 connects the third pipe 17 to the first pipe 13 so that the internal pneumatic pressure O of the reservoir 2 is applied to the first pipe 13. ). In this case, as described above, the first applied pressure of the first pipe 13 is controlled so that the internal pneumatic pressure O of the reservoir 2 connected thereto is controlled, and finally the pressure of the meniscus m is controlled. do.

Meanwhile, as described above, the ink inside the reservoir 2 may flow back to the third conduit 17. That is, when the first applied pressure is applied as a negative pressure and the reservoir 2 is filled with ink, the ink inside the reservoir 2 may be sucked through the third pipe 17 and some of the ink may flow backward. have. In this case, the backflow sensor S may detect the backflow of ink and transmit it to the control unit 90.

The controller 90 controls the third valve 51 when the reverse flow of ink is detected by the reverse flow sensor S. The control unit 90 controls the third valve 51 to connect the third pipe 17 to the fourth pipe 19 as shown in (b) of FIG. 20. That is, the control unit 90 connects the third conduit 17 to the fourth conduit 19 so that the ink flowing back to the third conduit 17 can be discharged to the drain tank T. In this case, the ink existing in the third pipe 17 may flow to the drain tank T along the fourth pipe 19 as shown in the direction c shown in FIG. 19 to be accommodated in the drain tank T.

Since the ink flowing back into the third pipe 17 is recovered to the drain tank T, it is possible to prevent malfunction of the ink jet nozzle micropressure control device 1, and reuse of the ink recovered to the drain tank T is possible. It becomes possible. When the recovery of the ink flowing back to the drain tank T is finished, the third valve 51 may reconnect the first pipe 13 and the third pipe 17.

As described above, those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

The scope of the present invention is indicated by the scope of the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention. It must be interpreted.

100: body 31: first valve
51: third valve S: backflow detection sensor

Claims (8)

A supply pipe to which pressure is applied;
A first conduit through which the internal pneumatic pressure of the reservoir in which the ink is accommodated is applied;
A second pipe through which the other end is connected to the outside atmosphere;
A first valve provided between the supply pipe and the first pipe, connected to the second pipe, and opening and closing the supply pipe, the first pipe and the second pipe;
A first sensor measuring a first applied pressure applied to the first pipe; And
When the absolute value of the first applied pressure measured by the first sensor exceeds the absolute value of the target pressure, the first valve is controlled to increase the opening rate of the second pipe to set the first applied pressure to the target. A control unit controlling pressure;
Fine pressure control device of the inkjet nozzle comprising a.
The method of claim 1,
The first valve is a micro pressure control device of an inkjet nozzle which is a proportional control valve.
The method of claim 1,
The first valve is a fine pressure control device of an ink jet nozzle as a three-way valve.
The method of claim 3,
The first valve,
An upper port connected to the supply line;
A central port in communication with the upper port and connected to the first pipe;
A lower port communicating with the central port and connected to the second pipe;
A first seal provided between the upper port and the central port and opening and closing the supply pipe; And
A second seal provided between the central port and the lower port and configured to open and close the second conduit;
Fine pressure control device of the inkjet nozzle comprising a.
The method of claim 1,
A fine pressure control device for an inkjet nozzle further comprising an adapter having a hole formed at an end of the second pipe to communicate with the external atmosphere.
The method of claim 1,
The first sensor is a fine pressure control device of the ink jet nozzle provided at the end of the measuring pipe branched from the first pipe.
The method of claim 1,
A third pipe connected to the reservoir;
A backflow sensor provided between the third pipe and the reservoir;
A fourth pipe connected to a drain tank for accommodating ink; And
A third valve provided at a rear end of the first pipe and connecting the third pipe to either the first pipe or the fourth pipe;
Fine pressure control device of the inkjet nozzle further comprising a.
The method of claim 7,
The control unit controls the third valve to connect the third pipe to the fourth pipe.

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