Inkjet printhead

Abstract

The present invention relates to an inkjet print head having a plurality of nozzles and ejecting a solution by electrohydrodynamics, characterized by comprising: a first electrode formed for each of the plurality of nozzles and to which a voltage for ejecting the solution by electrohydrodynamics is applied; a first voltage controller for applying the voltage to the first electrode; and a second electrode disposed apart between the first electrodes formed on the respective nozzles and grounded, and for preventing interference of electric fields between the respective nozzles.

Description

Technical Field

[0001] This invention relates to an inkjet printhead, and more specifically to an inkjet printhead having multiple nozzles and ejecting a solution via electrohydrodynamics. Background Technology

[0002] Generally speaking, an inkjet printhead is a device that sprays tiny droplets of ink onto the desired location on a printing medium, thereby printing an image of a specified color on the surface of the medium. Recently, the application of inkjet printheads has expanded to various fields, including flat panel displays such as LCDs and OLEDs, flexible displays such as e-paper, printed electronics such as metal wiring, and the biotechnology field.

[0003] In drop-on-demand (DOD) inkjet printheads, depending on the ejection method, there are piezoelectric inkjet printheads that use pressure waves generated by the deformation of a piezoelectric element to eject ink, and electrohydrodynamic inkjet printheads that use electrostatic force to eject ink.

[0004] Piezoelectric inkjet printheads use a piezoelectric element to vibrate a film, thereby applying pressure to a chamber containing ink to eject ink. Generally, if pressure is applied sufficient to overcome the surface tension and viscosity of the ink on the nozzle surface, droplets will be ejected. Furthermore, the applied pressure should be sufficiently high to accelerate the ejected droplets to a speed that allows them to accurately land on the printing medium. In piezoelectrically driven inkjet printheads, to achieve droplets of a few picoliters or less, the deformation energy within the pressure chamber needs to be reduced. However, this also reduces the ejection energy per unit volume of the ejected droplets, resulting in a lower droplet ejection velocity. Such a reduction in droplet ejection velocity leads to the problem of not being able to accurately eject droplets to the desired location.

[0005] Piezoelectric inkjet printheads offer several advantages: they are easy to control during printing, and because the jetting energy is provided by the mechanical deformation of the piezoelectric element, the types of inks that can be used are unlimited. However, piezoelectric inkjet printheads also have limitations: they struggle to produce ultra-fine droplets smaller than a few picoliters, typically only able to jet inks with viscosities around 10 cPs, and unable to jet high-viscosity inks. Furthermore, due to limitations in jetting energy, they cannot jet larger droplets exceeding 80 picoliters. In particular, for applications in printed electronics such as displays, unlike conventional pattern printing, the uniformity of droplet volume across multiple nozzles is crucial; despite this, piezoelectric inkjet printheads still face limitations.

[0006] Electrohydrodynamic inkjet printheads provide ejection energy by applying electrostatic force to the surface of the ink formed at the nozzle tip. This allows for the ejection of ultra-microdroplets (a few picoliters or even liters) and high-viscosity ink droplets in the 1,000 cPs range. Furthermore, they can form larger droplets exceeding 80 picoliters. Because control is achieved through the distribution of the electric field formed on the nozzle, the drive mechanism is relatively simple, and the directionality of the ejected ink droplets is excellent, making it advantageous for precision printing.

[0007] However, when multiple nozzles are formed on the inkjet printhead of electrohydrodynamic inkjet, electric field interference will occur between adjacent nozzles, resulting in uneven droplet size ejected through multiple nozzles and a decrease in print quality.

[0008] [Prior Technology Documents]

[0009] Patent document: Korean Patent Publication No. 1310759 Summary of the Invention

[0010] The present invention is proposed to solve the problems mentioned above, and its object is to provide an inkjet printhead having multiple nozzles that eject droplets in an electrohydrodynamic manner. The inkjet printhead has grounded second electrodes spaced apart from first electrodes formed on each nozzle and ejecting droplets in an electrohydrodynamic manner, thereby preventing electric field interference between the nozzles.

[0011] The technical problem to be solved by this invention is not limited to the technical problems mentioned above. For other technical problems not mentioned, those skilled in the art should be able to understand them clearly based on the following description.

[0012] The above objective can be achieved by the inkjet printhead of the present invention, which has a plurality of nozzles and ejects a solution in an electrohydrodynamic manner, characterized in that it includes: a first electrode formed for each of the plurality of nozzles and subjected to a voltage for ejecting the solution in an electrohydrodynamic manner; a first voltage controller for applying a voltage to the first electrode; and a second electrode spaced apart from the first electrode formed on each nozzle and grounded, and used to prevent electric field interference between the nozzles.

[0013] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, a first electrode being formed on the inner side of the nozzle chambers, and a second electrode being formed on the upper side of the nozzle layer.

[0014] Preferably, the distance between the first electrode and the second electrode is greater than the distance between the lower end of the nozzle and the printed material.

[0015] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, and a downwardly recessed groove being formed on the upper side surface of the nozzle layer, with the second electrode formed inside the groove.

[0016] This may further include a blocking portion formed of an insulator and covering the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

[0017] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, a first electrode being formed on the inner side of the nozzle chambers, and a second electrode being formed on the lower side of the nozzle layer.

[0018] Here, for each nozzle, a protruding portion with a nozzle hole formed at the lower end of the nozzle layer is formed, and the second electrode is formed on the concave surface between the protruding portions.

[0019] Preferably, the distance between the lower end of the nozzle and the second electrode is greater than the distance between the lower end of the nozzle and the printed material.

[0020] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, and an upwardly recessed groove being formed on the lower side surface of the nozzle layer, with the second electrode formed inside the groove.

[0021] This may further include a blocking portion formed of an insulator and covering the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

[0022] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers; and a partition layer disposed above the nozzle layer and having a flow channel formed therethrough connecting to the nozzle chambers, wherein a first electrode is formed on the inner side of the nozzle chambers and a second electrode is formed on the upper side of the partition layer.

[0023] Here, the second electrode may be further formed on the lower side of the nozzle layer.

[0024] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers; and a partition layer disposed above the nozzle layer and having a flow channel formed through it and connected to the nozzle chambers, wherein a downwardly recessed groove is formed on the upper side surface of the partition layer, and the second electrode is formed inside the groove.

[0025] This may further include a blocking portion formed of an insulator and covering the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

[0026] Here, the nozzle layer may include: a first nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution formed at the lower end of the nozzle chambers, and a first electrode formed on the inner surface of the nozzle chambers; and a second nozzle layer formed above the first nozzle layer having a plurality of communicating chambers communicating with the nozzle chambers, and a third electrode formed on the inner surface of the communicating chambers, the third electrode being subjected to a voltage for ejecting solution by electrohydrodynamics.

[0027] Here, multiple nozzles can be configured in a matrix form. The first electrodes, arranged along one of the row or column directions, are electrically connected to each other, so that the first electrodes arranged along one direction are selectively and simultaneously applied voltage by the first voltage controller. The third electrodes, arranged along another of the row or column directions, are electrically connected to each other, so that the third electrodes arranged along another direction are selectively and simultaneously applied voltage by the second voltage controller for applying voltage.

[0028] Furthermore, the above-mentioned objective can be achieved by the inkjet printhead of the present invention, which has a plurality of nozzles and ejects solution in an electrohydrodynamic manner, characterized in that it includes: a first electrode formed for each of the plurality of nozzles and subjected to a voltage for ejecting solution in an electrohydrodynamic manner or grounded; a first voltage controller for applying a voltage to the first electrode; and a control unit for controlling the first electrode to be grounded or for the first electrode to be subjected to a voltage by the first voltage controller, wherein when the plurality of nozzles are selectively ejecting solution, the control unit connects the first electrode of the nozzle to be ejected to the first voltage controller so that the first electrode is subjected to a voltage, and grounds the first electrode of the nozzle adjacent to the nozzle to be ejected that does not eject solution.

[0029] Here, when multiple nozzles are selectively spraying solution, the control unit can connect the first electrode of the nozzle to be sprayed with solution to the first voltage controller so that the first electrode is energized, and ground the first electrode of the remaining nozzles that are not spraying solution.

[0030] Here, the inkjet printhead may include: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, wherein the first electrode may be formed on the inner surface of the nozzle chambers.

[0031] Here, the distance between the first electrodes of adjacent nozzles can be greater than the distance between the lower end of the nozzle and the printed material.

[0032] According to the inkjet printhead of the present invention as described above, droplets are ejected using multiple nozzles via electrohydrodynamics, which has the advantages of minimizing electric field interference between adjacent nozzles, making it easy to control, and enabling uniform droplet ejection.

[0033] In addition, it has the advantage of allowing independent control of each nozzle to spray droplets. Attached Figure Description

[0034] Figure 1 This is a schematic diagram showing the structure of the printhead according to the first embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram showing the structure of the printhead according to a second embodiment of the present invention.

[0036] Figure 3 This is a schematic diagram showing the structure of the printhead according to a third embodiment of the present invention.

[0037] Figure 4 This is a schematic diagram showing the structure of the printhead according to the fourth embodiment of the present invention.

[0038] Figure 5 This is a schematic diagram showing the structure of the printhead according to the fifth embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram showing the structure of a printhead according to a sixth embodiment of the present invention.

[0040] Figure 7 It means Figure 6 A diagram showing the voltage application structure of the first and third electrodes.

[0041] Figure 8 express Figure 7 An example of the operation.

[0042] Figure 9 This is a schematic diagram showing the structure of a printhead according to a seventh embodiment of the present invention. Detailed Implementation

[0043] The detailed description and accompanying drawings include specific details of the embodiments.

[0044] The advantages and features of the present invention, as well as the methods for achieving these advantages and features, should be clearly understood by referring to the accompanying drawings and the detailed embodiments described below. However, the present invention is not limited to the embodiments disclosed below and can be implemented in various different forms. These embodiments are provided merely to fully disclose the invention and to fully inform those skilled in the art of the invention of its scope; the invention should be defined by the scope of the claims. Throughout this specification, the same reference numerals denote the same structural elements.

[0045] The present invention will now be described in detail through embodiments thereof, with reference to the accompanying drawings illustrating the inkjet printhead.

[0046] Figure 1 This is a schematic diagram showing the structure of the printhead according to the first embodiment of the present invention.

[0047] The inkjet printhead according to the first embodiment of the present invention has a plurality of nozzles 100, each nozzle 100 ejecting a solution by electrostatic force using electrohydrodynamics. Although the figure shows two nozzles 100 formed along the horizontal direction, this is only for illustration, and a greater number of nozzles 100 can be formed. In addition, a plurality of nozzles 100 can also be arranged in the front and back paper direction, and the plurality of nozzles 100 can be formed in a matrix configuration.

[0048] Multiple nozzles 100 may be formed on the nozzle layer 110. Multiple nozzle chambers 112 for storing ink supplied from the outside are formed on the nozzle layer 110 at intervals, and nozzle holes 114 for spraying solution are formed at the lower end of the nozzle chambers 112. At this time, as shown in the figure, the nozzle chambers 112 may be formed in the form of a truncated cone with an inclined surface formed on the inside, with the cross-sectional size decreasing towards the lower part, but it is not limited to this, and the nozzle chambers 112 may also be formed in the form of a cylinder.

[0049] For each nozzle 100, a protrusion 115 may be formed at the lower end of the nozzle layer 110, and the nozzle hole 114 may be formed at the lower end of the protrusion 115.

[0050] Each of the plurality of nozzles 100 is provided with a first electrode 120, which is subjected to a voltage for jetting the solution via electrohydrodynamics. As shown, the first electrode 120 may be formed on the inner surface of the nozzle chamber 112. Although the first electrode 120 is formed on the entire inner surface of the nozzle chamber 112 in the figure, it may also be formed partially on a portion of the inner surface of the nozzle chamber 112. Furthermore, the upper end of the first electrode 120 may also extend partially to form on the upper surface of the nozzle layer 110.

[0051] Although not illustrated, the first electrode 120 may also be coated with an insulating layer. When the first electrode 120 is coated with an insulating layer, when a voltage is applied to the first electrode 120, the solution flowing into the nozzle chamber 112 can be induced to become charged by the voltage, and the solution can be sprayed to the outside through the nozzle orifice 114 by the force of the electric field formed by the first electrode 120.

[0052] The first electrode 120 can be formed independently for each nozzle 100. Alternatively, for multiple nozzles 100, the first electrode 120 can also be formed integrally. Furthermore, as shown in reference... Figures 7 to 8 As explained, the first electrode 120 can also be integrally formed with a plurality of nozzles 100 arranged in a row or column.

[0053] The first voltage controller 150 applies a voltage to the first electrode 120 for spraying the solution via electrohydrodynamics.

[0054] A ground electrode 200, which is either subjected to a voltage of opposite polarity to that applied to the first electrode 120 or grounded, can be formed below the printed object S. Alternatively, the ground electrode 200 may not be electrically connected. Furthermore, the ground electrode 200 may be omitted altogether. The ground electrode 200 and the first electrode 120 form a potential difference, thereby creating a more uniform electric field between the nozzle 100 and the printed object S for jetting via electrohydrodynamics.

[0055] The second electrode 130 is disposed at a distance from the first electrode 120 formed in each nozzle 100 and grounded. With the grounded second electrode 130 disposed between each nozzle 100, the electric field interference between adjacent nozzles 100 can be minimized.

[0056] In this embodiment, the second electrode 130 may be formed on the upper side of the nozzle layer 110 at a position between each nozzle 100 and spaced apart from the first electrode 120.

[0057] At this time, as Figure 1 As shown in the enlarged view, preferably, the distance B between the first electrode 120 and the second electrode 130 is greater than the distance A between the lower end of the nozzle 100 and the substrate S. In this case, the electric field interference between adjacent nozzles 100 can be minimized, thus allowing independent control of each nozzle 100 to spray the solution. When the distance B between the first electrode 120 and the second electrode 130 is less than the distance A between the lower end of the nozzle 100 and the substrate S, the electric field generated by the first electrode 120 of one nozzle 100 has a greater influence on adjacent nozzles 100 than on the effect of that electric field on the spraying of droplets onto the target substrate, making it difficult to control the solution to be sprayed independently through each nozzle 100. Of course, for independent control, the first electrode 120 should not be formed as a single unit for multiple nozzles 100, but should be formed independently. Here, the distance B between the first electrode 120 and the second electrode 130 can mean the minimum distance between the ends of the first electrode 120 and the second electrode 130.

[0058] The distance B between the first electrode 120 and the second electrode 130 is a fixed value during manufacturing. Therefore, when using the inkjet printhead of this embodiment, it is preferable to control the distance A between the lower end of the nozzle 100 and the printed object S within a range less than the value of B for printing.

[0059] Please also refer to, although in Figure 1 In this configuration, only one of the multiple first electrodes 120 is connected to the first voltage controller 150, but in reality, all the first electrodes 120 are connected to the first voltage controller 150 respectively. Furthermore, although in Figure 1 The diagram shows only one second electrode 130 grounded, but in reality all second electrodes 130 are grounded. The same applies to the remaining diagrams described later.

[0060] Figure 2 This is a schematic diagram showing the structure of the printhead according to a second embodiment of the present invention.

[0061] In the following description, referencing the preceding text. Figure 1 The differences between the described embodiments will be explained in detail.

[0062] In this embodiment, the shape and structure of the nozzle layer 110 and the first electrode 120 are the same as in the previous embodiment.

[0063] In this embodiment, a downwardly recessed groove 111 may be formed between each nozzle 100 on the upper side of the nozzle layer 110. The groove 111 may be formed in a shape where the length is greater than the width, but is not necessarily limited to this.

[0064] At this time, a grounded second electrode 130 can be formed inside the groove 111. Furthermore, after the second electrode 130 is formed inside the groove 111, a blocking portion 119 can be further formed, which covers the groove 111 to prevent the second electrode 130 from being exposed to the outside of the groove 111. Preferably, the blocking portion 119 is formed of an insulator.

[0065] With the grounded second electrode 130 formed in this structure inside the groove 111 covered by an insulator, electric field interference between adjacent nozzles 100 can be minimized.

[0066] Figure 3 This is a schematic diagram showing the structure of the printhead according to a third embodiment of the present invention.

[0067] In the following description, referencing the preceding text. Figure 1 The differences between the described embodiments will be explained in detail.

[0068] In this embodiment, the shape and structure of the nozzle layer 110 and the first electrode 120 are the same as in the previous embodiment.

[0069] In this embodiment, the second electrode 130 may be formed on the lower side of the nozzle layer 110 between the nozzles 100. At this time, since each nozzle 100 has a protrusion 115 formed below the nozzle layer 110 as described above, the second electrode 130 may be formed on the concave surface between the protrusions 115.

[0070] In this embodiment, it is preferable that the distance B between the lower end of the nozzle 100 and the second electrode 130 is greater than the distance A between the lower end of the nozzle 100 and the substrate S. In this case, the electric field interference between adjacent nozzles 100 can be minimized, thus allowing independent control of each nozzle 100 to spray the solution without wetting. However, when the distance B between the lower end of the nozzle 100 and the second electrode 130 is less than the distance A between the lower end of the nozzle 100 and the substrate S, it is difficult to control the solution to be sprayed independently through each nozzle 100, and wetting may occur. Here, the distance B between the lower end of the nozzle 100 and the second electrode 130 can be interpreted as the minimum distance between the end of the second electrode 130 and the lower end of the nozzle 100.

[0071] In this embodiment, the distance B between the lower end of the nozzle 100 and the second electrode 130 is a fixed value during manufacturing. Therefore, when using the inkjet printhead of this embodiment, it is preferable to control the distance A between the lower end of the nozzle 100 and the printed object S within a range less than the value of B for printing.

[0072] Although not illustrated, please refer to Figure 2 As explained, an upwardly recessed groove 111 may also be formed on the lower side of the nozzle layer 110, and a second electrode 130 may be formed inside the groove 111. Similarly, it is preferable to cover the groove 111 with a blocking portion 119, which serves as an insulator, thereby preventing the second electrode 130 from being exposed to the outside.

[0073] Figure 4 This is a schematic diagram showing the structure of the printhead according to the fourth embodiment of the present invention.

[0074] In the following description, the same references will be used as before. Figure 1 The differences between the described embodiments will be explained in detail.

[0075] In this embodiment, the shape and structure of the nozzle layer 110 and the first electrode 120 are the same as in the previous embodiment.

[0076] In this embodiment, a partition 140 may be further included above the nozzle layer 110. The partition 140 is disposed above the nozzle layer 110 and has a flow channel 142 formed therethrough, connecting to the nozzle chamber 112. The first electrode 120 is not formed inside the flow channel 142. The partition 140 may be formed from a wafer of a specified thickness.

[0077] At this time, a grounded second electrode 130 can be formed on the upper side of the partition 140. The second electrode 130 can prevent electric field interference between adjacent nozzles 100.

[0078] Compared to the first embodiment, in this embodiment, the distance B between the first electrode 120 and the second electrode 130 can be kept relatively far apart by the partition 140, so that the distance A between the lower end of the nozzle 100 and the printed object S can be kept further apart, and printing can be performed by independent control.

[0079] Although not illustrated, please refer to Figure 2 As explained, a downwardly recessed groove 111 may also be formed on the upper side of the partition 140, and a second electrode 130 may be formed inside the groove 111. Similarly, it is preferable to cover the groove 111 with a blocking portion 119, which serves as an insulator, thereby preventing the second electrode 130 from being exposed to the outside.

[0080] Figure 5 This is a schematic diagram showing the structure of the printhead according to the fifth embodiment of the present invention.

[0081] In the following description, the same references will be used as before. Figures 1 to 4 The differences between the described embodiments will be explained in detail.

[0082] In this embodiment, the shape and structure of the nozzle layer 110 and the first electrode 120 are the same as in the previous embodiment. Furthermore, the second electrode 130 is formed on the upper side of the nozzle layer 140, as described above. Figure 4 The illustrated embodiment is the same. In this embodiment, it is consistent with the previous reference. Figure 4 Compared to the illustrated embodiments, such as Figure 3 As shown in the embodiment, a grounded second electrode 130 is also formed on the lower side of the nozzle layer 110.

[0083] That is, in this embodiment, grounded second electrodes 130b and 130a are formed on the upper side of the partition layer 140 and the lower side of the nozzle layer 110, respectively, thereby preventing electric field interference between adjacent nozzles 100.

[0084] Although not illustrated, it can be referenced as follows. Figure 2 The second electrode 130b is formed inside a downwardly recessed groove on the upper side of the partition layer 140, or an upwardly recessed groove is formed inside a groove on the lower side of the nozzle layer 110, and the second electrode 130a is disposed inside the groove. Similarly, it is preferable that the grooves formed on the partition layer 140 or the nozzle layer 110 are covered by blocking portions acting as insulators, thereby preventing the second electrodes 130a and 130b from being exposed to the outside.

[0085] Figure 6 This is a schematic diagram showing the structure of the printhead according to the sixth embodiment of the present invention. Figure 7 It means Figure 6 A diagram showing the voltage application structure of the first and third electrodes. Figure 8 express Figure 7 An example of the operation.

[0086] In this embodiment, the nozzle layer 110 can be formed separately from the first nozzle layer 110_1 and the second nozzle layer 110_2.

[0087] The first nozzle layer 110_1 is located below the second nozzle layer 110_2 and has a plurality of nozzle chambers 112 for storing ink. A nozzle orifice 114 for spraying solution is formed at the lower end of each nozzle chamber 112. In addition, a first electrode 120_1 may be formed on the inner surface of the nozzle chamber 112.

[0088] The second nozzle layer 110_2 is formed above the first nozzle layer 110_1 and has a through chamber 116 that communicates with the nozzle chamber 112 of the first nozzle layer 110_1. A third electrode 120_2 is formed on the inner surface of the through chamber 116, on which a voltage is applied for jetting the solution via electrohydrodynamics. The first electrode 120_1 and the third electrode 120_2 are separate from each other and are not connected to each other. The first electrode 120_1 is connected to the first voltage controller 150_1 and is energized, and the third electrode 120_2 is connected to the second voltage controller 150_2 and is energized.

[0089] Both the first electrode 120_1 and the third electrode 120_2 can be electrodes that form an electric field between the nozzle 100 and the printed object S by spraying the solution through electrohydrodynamics.

[0090] Furthermore, the aforementioned partition layer 140 may be formed above the second nozzle layer 110_2. A grounded second electrode 130 may be formed on the upper side of the partition layer 140 to prevent electric field interference between adjacent nozzles 100.

[0091] Although not illustrated, it can also be seen as Figure 1 As shown, a second electrode 130, spaced apart from the first electrode 120_1 and grounded, is formed on the upper surface of the first nozzle layer 110_1. Furthermore, a second electrode 130, spaced apart from the third electrode 120_2 and grounded, may also be formed on the upper surface of the second nozzle layer 110_2. Additionally, although not shown, it may be as follows... Figure 3 A grounded second electrode 130 is formed on the lower side surface of the second nozzle layer 110_2 as shown. Furthermore, as shown in reference... Figure 2 As described above, grooves 111 are formed on the first nozzle layer 110_1 and the second nozzle layer 110_2, and a second electrode 130 is disposed inside the grooves 111.

[0092] In this embodiment, the first electrode 120_1 and the third electrode 120_2, which are subjected to voltage, can be synchronized and spray the solution through electrohydrodynamics.

[0093] As previously described, the inkjet printhead according to this embodiment can have multiple nozzles 100 arranged in a matrix along both the row and column directions. Figure 8 The diagram schematically illustrates the connection structure of the first electrode 120_1 and the third electrode 120_2 of the multi-nozzle 100 arranged in a three-row, seven-column configuration, but is not limited to this.

[0094] At this point, multiple third electrodes 120_2 arranged along a row or column direction can be electrically connected in a straight line. Figure 7 and Figure 8The seven third electrodes 120_2 in the row direction are electrically connected (represented by a, b, and c), and are electrically connected to the second voltage controller 150_2 in three rows. Furthermore, multiple first electrodes 120_1 arranged along either the row or column direction can also be electrically connected in a straight line. In this case, the electrical connection directions of the first electrodes 120_1 and the third electrodes 120_2 can be orthogonal to each other; that is, when the third electrodes 120_2 are electrically connected along the row direction, the first electrodes 120_1 can be electrically connected along the column direction. Figure 7 and Figure 8 The three first electrodes 120_1 in the middle column direction are electrically connected (represented by 1, 2, 3, 4, 5, 6 and 7), and connected to the first voltage controller 150_1 in seven columns.

[0095] When multiple first electrodes 120_1 and third electrodes 120_2 are independently connected to the first voltage controller 150_1 and the second voltage controller 150_2, respectively, the voltage connection structure (circuit) may become complex. When the voltage connection structure becomes complex, the distance between the nozzles 100 increases, making it impossible to compactly arrange the multiple nozzles 100. Furthermore, if voltage is applied to the first electrodes 120_1 and the third electrodes 120_2 independently, it may create a capacity burden on the voltage controller 150. However, by electrically connecting multiple electrodes arranged along the row or column direction using multiple first electrodes 120_1 and third electrodes 120_2 as in this embodiment, the voltage connection structure is simplified, and the capacity burden on the voltage controller 150 is alleviated.

[0096] When a droplet is ejected through a portion of the configured plurality of nozzles 100, a voltage can be applied to a line connected to a first electrode 120_1 and a third electrode 120_2 corresponding to the respective nozzle 100 to eject the droplet.

[0097] For example in Figure 8 In this configuration, lines b and 5 can be in the ON state, while lines a, c, 1, 2, 3, 4, 6, and 7 can be in the OFF state. At this time, only the nozzle 100 at the intersection of lines b and 5 can spray solution. Thus, by electrically connecting the first electrode 120_1 and the third electrode 120_2 in a straight line along either the row or column direction, and selectively applying voltage to each row or column, solution can be selectively sprayed from multiple nozzles 100.

[0098] Figure 9 This is a schematic diagram showing the structure of an inkjet printhead according to a seventh embodiment of the present invention.

[0099] The inkjet printhead of this embodiment can be configured to include a first electrode 120, a first voltage controller 150, and a control unit 160.

[0100] Similar to the previous embodiments, the inkjet printhead of this embodiment has a plurality of nozzles 100, each nozzle 100 can spray solution by electrostatic force using electrohydrodynamics.

[0101] Multiple nozzles 100 may be formed on the nozzle layer 110. The structure of the nozzle layer 110 is the same as in the previous embodiment, so the description is omitted.

[0102] The first electrode 120 is configured for each of the plurality of nozzles 100 and is applied a voltage for jetting the solution via electrohydrodynamics. Similar to the previous embodiment, the first electrode 120 may be formed on the inner surface of the nozzle chamber 112. Furthermore, it may be coated with an insulating layer.

[0103] In this embodiment, the first electrode 120 may be energized by the first voltage controller 150 or grounded.

[0104] The first voltage controller 150 applies a voltage to the first electrode 120 for spraying the solution via electrohydrodynamics.

[0105] The control unit 160 can control the first electrode 120 to be grounded, or control the application of voltage to the first electrode 120 by the first voltage controller 150. For example... Figure 9 As shown, the control unit 160 can control the switch formed between the first electrode 120 and the first voltage controller 150, thereby electrically connecting the first electrode 120 and the first voltage controller 150 through the switch, or controlling the first electrode 120 to be grounded.

[0106] In this embodiment, when multiple nozzles 100 selectively spray solution, the control unit 160 can control the first electrode 120 of the nozzle 100 to be sprayed with solution to be connected to the first voltage controller 150 so that the first electrode is energized with voltage, and control the first electrode 120 of the nozzle 100 adjacent to the nozzle 100 to be sprayed with solution but not spraying solution to be grounded. Figure 9 In the middle, the control unit 160 connects the first electrode 120 of the left nozzle 100 to the first voltage controller 150 and grounds the first electrode 120 of the right nozzle 100, so that the solution is sprayed by the left nozzle 100 only through electrohydrodynamics.

[0107] Compared to the previous embodiments, there is no grounded second electrode 130 in this embodiment. Instead, in this embodiment, the electric field interference between the nozzles 100 that spray solution can be minimized by grounding the first electrode 120 of the nozzle 100 that does not spray solution and is adjacent to the nozzle 100 that sprays solution.

[0108] At this time, the control unit 160 can not only control the nozzle 100 adjacent to the nozzle 100 that is to be sprayed with solution to be grounded, but also control the first electrode 120 of all the remaining nozzles 100 that are not spraying solution to be grounded.

[0109] At this time, as Figure 9 As shown, the distance B between the first electrodes 120 of adjacent nozzles 100 is preferably greater than the distance A between the lower end of the nozzle 100 and the workpiece S. In this case, the electric field interference between adjacent nozzles 100 can be minimized, and thus each nozzle 100 can be independently controlled to spray the solution.

[0110] The distance B between the first electrodes 120 of adjacent nozzles 100 is a fixed value during manufacturing. Therefore, when using the inkjet printhead of this embodiment, it is preferable to control the distance A between the lower end of the nozzle 100 and the printed object S within a range less than the value of B for printing.

[0111] The scope of this invention is not limited to the embodiments described above, and various embodiments can be implemented within the scope of the appended claims. Various modifications that can be made by those skilled in the art without departing from the spirit of the invention as claimed in the claims also fall within the scope of the claims.

[0112] Explanation of reference numerals in the attached figures

[0113] 100: Nozzle

[0114] 110: Nozzle layer

[0115] 111: Slot

[0116] 112: Nozzle chamber

[0117] 114: Nozzle orifice

[0118] 115: Protrusion

[0119] 116: Connecting chambers

[0120] 119: Blocking section

[0121] 120: First electrode

[0122] 130: Second electrode

[0123] 140: Mezzanine

[0124] 150: First voltage controller

[0125] 160: Control Department

[0126] 200: Grounding electrode

Claims

1. An inkjet printhead having multiple nozzles and ejecting a solution via electrohydrodynamics, characterized in that, include: The first electrode is formed for each of the plurality of nozzles and is subjected to a voltage for ejecting the solution via electrohydrodynamics. A first voltage controller is used to apply a voltage to the first electrode; a second electrode is disposed at a distance from the first electrode formed on each nozzle and grounded, and is used to prevent electric field interference between the nozzles. The nozzle layer has a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for spraying solution is formed at the lower end of the nozzle chamber, wherein the first electrode is formed on the inner side of the nozzle chamber, and the second electrode is formed between adjacent first electrodes.

2. The inkjet printhead according to claim 1, characterized in that, The second electrode is formed on the upper side of the nozzle layer.

3. The inkjet printhead according to claim 2, characterized in that, The distance between the first electrode and the second electrode is greater than the distance between the lower end of the nozzle and the printed material.

4. The inkjet printhead according to claim 1, characterized in that, A downwardly recessed groove is formed on the upper side surface of the nozzle layer, and the second electrode is formed inside the groove.

5. The inkjet printhead according to claim 4, characterized in that, Further includes: The blocking portion is formed of an insulator and covers the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

6. The inkjet printhead according to claim 1, characterized in that, The second electrode is formed on the lower side of the nozzle layer.

7. The inkjet printhead according to claim 6, characterized in that, For each nozzle, a protruding portion is formed at the lower end of the nozzle layer, and a nozzle orifice is formed at the lower end. The second electrode is formed on the concave surface between the protruding portions.

8. The inkjet printhead according to claim 6, characterized in that, The distance between the lower end of the nozzle and the second electrode is greater than the distance between the lower end of the nozzle and the printed material.

9. The inkjet printhead according to claim 1, characterized in that, An upwardly recessed groove is formed on the lower side surface of the nozzle layer, and the second electrode is formed inside the groove.

10. The inkjet printhead according to claim 9, characterized in that, Further includes: The blocking portion is formed of an insulator and covers the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

11. The inkjet printhead according to claim 1, characterized in that, Further includes: A partition layer is disposed above the nozzle layer and has a flow channel that is connected to the nozzle chamber. The second electrode is formed on the upper side of the partition layer.

12. The inkjet printhead according to claim 11, characterized in that, The second electrode is further formed on the lower side of the nozzle layer.

13. The inkjet printhead according to claim 1, characterized in that, Further includes: A partition layer is disposed above the nozzle layer and has a flow channel that connects to the nozzle chamber. A downwardly recessed groove is formed on the upper side of the partition layer, and the second electrode is formed inside the groove.

14. The inkjet printhead according to claim 13, characterized in that, Further includes: The blocking portion is formed of an insulator and covers the groove, thereby preventing the second electrode from being exposed to the outside of the groove.

15. The inkjet printhead according to claim 2, characterized in that, The nozzle layer includes: a first nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution formed at the lower end of the nozzle chambers, and a first electrode formed on the inner surface of the nozzle chambers; and a second nozzle layer formed above the first nozzle layer, having a plurality of communicating chambers communicating with the nozzle chambers, and a third electrode formed on the inner surface of the communicating chambers, the third electrode being subjected to a voltage for ejecting solution via electrohydrodynamics.

16. The inkjet printhead according to claim 15, characterized in that, Multiple nozzles are arranged in a matrix configuration. The first electrodes, arranged along one of the row or column directions, are electrically connected to each other, so that voltage is selectively applied to the first electrodes arranged along one direction simultaneously via the first voltage controller. The third electrodes, arranged along another of the row or column directions, are electrically connected to each other, so that voltage is selectively applied to the third electrodes arranged along another direction simultaneously via the second voltage controller for applying voltage.

17. An inkjet printhead having multiple nozzles and ejecting a solution via electrohydrodynamics, characterized in that, include: The first electrode is formed for each of the plurality of nozzles and is either applied a voltage for ejecting the solution via electrohydrodynamics or grounded. A first voltage controller is configured to apply voltage to the first electrode; and a control unit is configured to control the first electrode to be grounded or to apply voltage to the first electrode by the first voltage controller. When multiple nozzles are selectively spraying solution, the control unit connects the first electrode of the nozzle to be sprayed with solution to the first voltage controller so that the first electrode is energized, and grounds the first electrode of the remaining nozzles that are not spraying solution.

18. The inkjet printhead according to claim 17, characterized in that, The inkjet printhead includes: a nozzle layer having a plurality of nozzle chambers for storing ink supplied to each nozzle, and a nozzle orifice for ejecting solution being formed at the lower end of the nozzle chambers, and a first electrode being formed on the inner surface of the nozzle chambers.

19. The inkjet printhead according to claim 18, characterized in that, The distance between the first electrodes of adjacent nozzles is greater than the distance between the lower end of the nozzle and the printed material.

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