Inkjet head

Abstract

To solve the problem that ink particles dispersed in ink as a pigment, conductive fine particles, and particles containing the pigment and the conductive fine particles and a curable resin have dispersion concentration which may become ununiform by a local sedimentation phenomenon or the like, in an ink storage chamber.SOLUTION: An inkjet head includes: (1) a head body having a storage chamber capable of storing ink; (2) a first inflow pipe and a second inflow pipe that are connected to the head body and into which the ink can flow from mutually different directions; (3) a first outflow pipe and a second outflow pipe that are connected to the head body and by which the ink can discharge to mutually different directions; and (4) a nozzle plate which is positioned below the head body and includes a plurality of nozzles.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to an inkjet head.

Background Art

[0002] An inkjet device includes an inkjet head having nozzles for ejecting ink. The inkjet head can eject ink from a plurality of nozzle holes formed on a nozzle surface. The inkjet head can form wirings of a display panel, form color filters, or form many thin films such as spacers by ejecting a conductive material, a color filter material, a curable material, or an insulating material as ink onto a substrate.

[0003] The ink can contain particles for each of the above materials together with a solvent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the particles in the ink have a relatively large specific gravity, they tend to settle in the inkjet head.

[0006] Embodiments prevent the concentration of the ejected ink from changing according to the nozzle position due to non-uniform sedimentation variation of the ink particles in the inkjet head, prevent functional deviation of the thin film of the display panel printed using the inkjet head, and prevent defects such as bleeding of images.

[0007] Furthermore, it prevents unnecessary operations such as ink purging to control variations in ink density ejected from the inkjet head nozzles, thereby preventing waste of ink materials and reducing ink material costs. [Means for solving the problem]

[0008] An inkjet head according to one embodiment includes a head body having a storage chamber capable of storing ink, a first inlet pipe and a second inlet pipe connected to the head body and capable of introducing ink from different directions, a first outlet pipe and a second outlet pipe connected to the head body and capable of discharging ink in different directions, and a nozzle plate located at the bottom of the head body and containing a plurality of nozzles.

[0009] The first inlet pipe and the second inlet pipe may be located on the side of the first edge of the head body, and the first outlet pipe and the second outlet pipe may be located on the side of the second edge of the head body facing the first edge.

[0010] The first inlet pipe and the first outlet pipe are formed in a first direction, and the second inlet pipe and the second outlet pipe may be formed in a second direction perpendicular to the first direction.

[0011] The storage chamber may include a first filter and a second filter located within the storage chamber and extending in different directions from each other.

[0012] The first filter may extend parallel to the nozzle plate and overlap with the first inlet pipe and the first outlet pipe on the first plane (plan view of the first plane), while the second filter may be located inside the second inlet pipe and overlap with the second inlet pipe on the second plane (plan view of the second plane).

[0013] The first filter may be located below the first inlet pipe and the first outlet pipe, and above the second inlet pipe and the second outlet pipe.

[0014] The system may further include a third filter located within the storage chamber and separated from the inner surface of the head body.

[0015] The third filter is connected to the first filter and the second filter, and the third filter may extend in the direction in which the second filter is extended.

[0016] The present invention further includes a cover plate located within the storage chamber and between the first filter and the nozzle plate, wherein the cover plate is located below the second inlet pipe and may overlap the plurality of nozzles on the first plane (plan view of the first plane).

[0017] The cover plate includes a pair of edges adjacent to two opposing edges on the inner surface of the head body, and a central portion located between the pair of edges and connected to the pair of edges, wherein the width of the central portion in one direction may be smaller than the width of the edges in that direction.

[0018] The edge portion may be in contact with the inner surface of the head body, while the central portion may be separated from the inner surface of the head body.

[0019] The cover plate may include one or more holes inside.

[0020] The aforementioned holes do not necessarily have to overlap with the plurality of nozzles on a plane (a plan view of the plane along the nozzle plate).

[0021] The cover plate may have a mesh or net-like structure.

[0022] The head body includes a first flow control unit located on the bottom surface and not overlapping with the plurality of nozzles on a first plane, wherein the first flow control unit is located between the outer nozzle row and the inner surface of the head body among a plurality of nozzle rows in which the plurality of nozzles are formed, and the first flow control unit may extend along the outer nozzle row.

[0023] It is further provided with a second flow control portion which is located above the bottom surface of the head body and does not overlap with the plurality of nozzles in the plan view of the first plane, the second flow control portion is located between two adjacent nozzle rows which are located inside among the plurality of nozzle rows, and the second flow control portion can be extended along the inner nozzle row.

[0024] The first flow control portion and the second flow control portion have a sharp upper form, and the height of the second flow control portion may be higher than the height of the first flow control portion.

[0025] An inkjet head according to an embodiment includes a head body having a storage chamber capable of storing ink, a first inflow pipe and a second inflow pipe connected to the head body, a first outflow pipe and a second outflow pipe connected to the head body, a nozzle plate located at a lower portion of the head body and including a plurality of nozzles, and a first filter and a second filter located in the storage chamber and extended in different directions from each other, the first filter is extended parallel to the nozzle plate and overlaps with the first inflow pipe in the plan view of the first plane, the second filter is located inside the second inflow pipe and overlaps with the second inflow pipe on the second plane (plan view of the second plane), and the ink includes at least one of quantum dots and scatterers.

[0026] An inkjet head according to an embodiment includes a head body having a storage chamber capable of storing ink, one or more inflow pipes and one or more outflow pipes connected to the head body, a nozzle plate located at a lower portion of the head body and including a plurality of nozzles, a filter located in the storage chamber and overlapping with the inflow pipe, and a cover plate located in the storage chamber and located between the filter and the nozzle plate, the cover plate overlaps with the plurality of nozzles on the plane (plan view), and the cover plate includes one or more holes inside.

[0027] An inkjet head according to an embodiment includes a head body having a storage chamber capable of storing ink, one or more inflow pipes and one or more outflow pipes connected to the head body, a nozzle plate located at a lower portion of the head body and including a plurality of nozzles, and a first flow control portion and a second flow control portion located on a bottom surface of the head body and not overlapping the plurality of nozzles on a plane. The first flow control portion is located between an outer nozzle row among a plurality of nozzle rows in which the plurality of nozzles are formed and an inner surface of the head body, the first flow control portion extends along the outer nozzle row, the second flow control portion is located between two adjacent nozzle rows located inside among the plurality of nozzle rows, and the second flow control portion extends along the inner nozzle row.

[0028] The first flow control portion and the second flow control portion have a form with a pointed upper portion, and the height of the second flow control portion may be higher than the height of the first flow control portion.

Advantages of the Invention

[0029] According to the embodiment, by preventing the concentration of the ink ejected according to the position of the nozzle from changing due to the variation in the non-uniform sedimentation of the ink particles in the inkjet head, it is possible to prevent the deviation of the function of the thin film of the display panel printed using the inkjet head and prevent defects such as bleeding of the image.

[0030] In addition, it is possible to prevent unnecessary operations such as ink purge performed for controlling the concentration variation of the ink ejected from the nozzles of the inkjet head, prevent waste of the ink material, and reduce the ink material cost.

Brief Description of the Drawings

[0031] [Figure 1] It is a plan view of an inkjet head according to an embodiment. [Figure 2] It is a plan view of an inkjet head according to an embodiment. [Figure 3]Figure 1 is a cross-sectional view of the inkjet head along the line A1-A2. [Figure 4] Figure 1 is a cross-sectional view of the inkjet head along the line B1-B2. [Figure 5] This is a plan view of an inkjet head according to one embodiment. [Figure 6] Figure 5 is a cross-sectional view of the inkjet head along the line A1-A2. [Figure 7] Figure 5 is a cross-sectional view of the inkjet head along the line B1-B2. [Figure 8] This is a plan view of an inkjet head according to one embodiment. [Figure 9] Figure 8 is a cross-sectional view of the inkjet head along the A1-A2 line. [Figure 10] Figure 8 is a cross-sectional view of the inkjet head shown along the line B1-B2. [Figure 11] This is a plan view of an inkjet head according to one embodiment. [Figure 12] Figure 11 is a cross-sectional view of the inkjet head along the line A1-A2. [Figure 13] Figure 11 is a cross-sectional view of the inkjet head along the line B1-B2. [Modes for carrying out the invention]

[0032] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. The present invention can be realized in a variety of different forms and is not limited to the embodiments described herein.

[0033] To clearly explain the present invention, unnecessary explanatory parts have been omitted, and the same or similar reference numerals have been used throughout the specification for identical or similar components.

[0034] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrarily indicated for the sake of explanation, and the present invention is not necessarily limited to what is shown. In the drawings, the thicknesses are shown enlarged to clearly represent multiple layers and regions. Also, in the drawings, the thicknesses of some layers and regions are shown exaggerated for the sake of explanation.

[0035] Furthermore, when a part such as a layer, membrane, region, or plate is said to be "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when one part is said to be "directly above" another part, it means that there is no other part in between. Also, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "up" in the opposite direction of gravity.

[0036] Furthermore, when a specification states that a certain part "includes" a certain component, unless otherwise stated, this means that other components are not excluded and other components may be included.

[0037] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above or from a direction perpendicular to a specific plane, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0038] An inkjet head according to one embodiment will be described with reference to Figures 1 to 4.

[0039] Figures 1 and 2 are plan views of an inkjet head according to one embodiment, Figure 3 is a cross-sectional view of the inkjet head shown in Figure 1 along the line A1-A2, and Figure 4 is a cross-sectional view of the inkjet head shown in Figure 1 along the line B1-B2.

[0040] An inkjet head 1000 according to one embodiment includes a head body 800, a plurality of inlet pipes 310p, 330p, a plurality of outlet pipes 320p, 340p, a nozzle plate 100, a first filter 410, a second filter 420, and a cover plate 500.

[0041] The print head body 800 has a storage chamber 810 in which ink can be stored. The print head body 800 has an inner surface 801.

[0042] Ink can vary depending on the purpose of the inkjet device, including the inkjet head. For example, ink can include conductive materials, color filter materials, curable materials, insulating materials, light-emitting layers, or color conversion layer materials, and the ink can be ejected onto a substrate to form many films such as wiring, color filters, spacers, and light-emitting layers for display panels.

[0043] The light-emitting layer or color-converting layer material contained in the ink may include, for example, semiconductor nanocrystals, and the semiconductor nanocrystals may include at least one of phosphors, quantum dots, and scatterers. Quantum dots may have a core-shell structure including a core containing semiconductor nanocrystals and a shell surrounding the core.

[0044] The ink contains particles for each of the aforementioned materials along with a solvent.

[0045] The multiple inlet pipes may include a first inlet pipe 310p and a second inlet pipe 330p, each having an inlet that allows ink to flow in from different directions, and the multiple outlet pipes may include a first outlet pipe 320p and a second outlet pipe 340p, each having an outlet that allows ink to be discharged in different directions.

[0046] The first inlet pipe 310p has a first inlet 310 into which ink can flow. The first inlet pipe 310p can be located on the side facing the nozzle plate 100 and can be located on the edge of the head body 800. The first inlet 310 and the first inlet pipe 310p can be formed in the z direction (perpendicular to the nozzle plate 100), but are not limited thereto. The first inlet 310 is connected to the storage chamber 810.

[0047] The first outflow pipe 320p has a first outlet 320 from which ink can be discharged. The first outflow pipe 320p can be located on the side facing the nozzle plate 100 and on the edge of the head body 800 opposite to the edge where the first inflow pipe 310p is located. The first outlet 320 and the first outflow pipe 320p may, but are not limited to, be formed in the z direction. The first outlet 320 is connected to the storage chamber 810.

[0048] The second inlet pipe 330p has a second inlet 330 into which ink can flow. The second inlet pipe 330p can be located on the edge of the head body 800 where the first inlet pipe 310p is located. The second inlet 330 and the second inlet pipe 330p may be formed in the y direction perpendicular to the z direction (the longitudinal direction of the nozzle plate 100), but are not limited thereto. The second inlet 330 is connected to the storage chamber 810.

[0049] The second outflow pipe 340p has a second outlet 340 from which ink can be discharged. The second outflow pipe 340p can be located on the edge of the head body 800 where the first outflow pipe 320p is located, and can be located opposite the second inflow pipe 330p. The second outlet 340 and the second outflow pipe 340p can be formed in the y direction, but are not limited thereto. The second outlet 340 is connected to the storage chamber 810.

[0050] The first inlet pipe 310p and the second inlet pipe 330p are located on one side edge (e.g., the left edge) of the head body 800, while the first outlet pipe 320p and the second outlet pipe 340p can be located on the other side edge (e.g., the right edge) of the head body 800 that faces the first side edge.

[0051] The nozzle plate 100 is located at the bottom of the print head body 800 and includes a plurality of nozzles 110, which are holes from which ink 10 can be ejected downwards.

[0052] Multiple nozzles 110 can be arranged in multiple nozzle rows 115a, 115b, 115c, and 115d on the xy-plane. The nozzle rows 115a, 115b, 115c, and 115d can each be formed in the y-direction. Referring to Figures 1 and 2, an example is shown in which multiple nozzles 110 are arranged in four nozzle rows 115a, 115b, 115c, and 115d, but the number of nozzle rows is not limited to this.

[0053] Within each nozzle row, a piezoelectric element 200 can be positioned on the nozzle plate 100 between adjacent nozzles 110. When a drive signal is applied to the piezoelectric element 200, the deformation of the piezoelectric element 200 causes the nozzles 110 to contract or expand, allowing ink to be easily ejected.

[0054] An inkjet head 1000 can be formed in such a way that a first inlet pipe 310p, a first outlet pipe 320p, a second inlet pipe 330p, a second outlet pipe 340p, and a nozzle plate 100 are formed on the head body 800, or are connected and joined together.

[0055] The nozzle plate 100 is located at the bottom of the head body 800, and the first inlet pipe 310p, the first outlet pipe 320p, the second inlet pipe 330p, and the second outlet pipe 340p are located above the nozzle plate 100. The second inlet pipe 330p and the second outlet pipe 340p can be located below the first inlet pipe 310p and the first outlet pipe 320p, respectively. Here, the vertical direction is based on the z-direction and remains the same thereafter.

[0056] The first filter 410 is located within the storage chamber 810, extends in the xy-plane, and may be parallel to the nozzle plate 100. Referring to Figures 1 and 3, the first filter 410 can overlap most of the internal space of the head body 800. In this case, as shown in Figures 1 and 3, the edge of the first filter 410 can be in contact with the inner surface 801 of the head body 800.

[0057] The storage chamber 810 can be divided into an upper region and a lower region with the first filter 410 as the boundary.

[0058] The first filter 410 can be located below the first inlet pipe 310p and the first outlet pipe 320p, and above the second inlet pipe 330p and the second outlet pipe 340p. In the xy plane, the first filter 410 can overlap the first inlet pipe 310p and the first outlet pipe 320p.

[0059] The first filter 410 blocks impurities other than the ink material particles 11 in the ink that flows in from the first inlet 310, and then allows the ink to pass to the other side of the first filter 410. For this purpose, the first filter 410 can have pores of a size that allows the ink material particles 11 to pass through, while blocking larger impurities.

[0060] In Figures 3 and 4, the ink flowing in as a straight arrow pointing downward in the z direction can move downward after impurities have been removed, passing through the first filter 410. The impurities can then move along the top of the first filter 410, as shown by the straight arrow pointing y on the first filter 410 in Figure 3, and then be discharged to the outside through the first outlet 320 as a straight arrow pointing upward in the z direction.

[0061] The first filter 410 may be omitted depending on the embodiment.

[0062] The second filter 420 is located within the storage chamber 810 and may extend in the xz plane. The second filter 420 may be located inside the second inlet 330 and may be located at the boundary between the second inlet 330 and the storage chamber 810. In other words, the second filter 420 may overlap the second inlet 330 and the second inlet pipe 330p in the xz plane.

[0063] The second filter 420 can send the ink to the storage chamber 810 after blocking the inflow of impurities other than the ink material particles 11 in the ink flowing in from the second inlet 330. For this purpose, the second filter 420 can have pores of a size that allows the ink material particles 11 to pass through but blocks larger impurities.

[0064] The second filter 420 may have the same material and structure as the first filter 410. The second filter 420 may be connected to or separated from the first filter 410.

[0065] In Figure 3, the ink flowing into the second inlet 330 as indicated by the straight arrow in the y direction can flow into the storage chamber 810 after impurities have been removed through the second filter 420.

[0066] The cover plate 500 is located within the storage chamber 810 and may extend in the xy plane (a plane parallel to the nozzle plate 100). The cover plate 500 may be located between the first filter 410 and the nozzle plate 100 and below the second inlet 330.

[0067] Referring to Figures 1 to 4, the cover plate 500 can overlap with multiple nozzles 110 on the xy plane.

[0068] The cover plate 500 can prevent the ink material particles 11 that have flowed into the storage chamber 810 from immediately settling toward the nozzle 110.

[0069] The cover plate 500 may have a continuous plane. On the xy plane, the cover plate 500 may include two side edges 501 and a central portion 502 between them. The central portion 502 may be connected to the pair of edges 501 or may be formed integrally with the edges 501.

[0070] The edges 501 on both sides can be located in areas adjacent to the left and right edges on the inner surface 801 of the head body 800, where the first inlet 310, the second inlet 330, the first outlet 320, and the second outlet 340 are located. The edges 501 can overlap the first inlet 310 or the first inlet pipe 310p, and the first outlet 320 and the first outlet pipe 320p in the xy plane.

[0071] The edge portion 501 prevents the ink flowing into the storage chamber 810 through the first inlet 310, the second inlet 330, the first outlet 320, and the second outlet 340 from circulating and from immediately settling into the nozzle 110.

[0072] The edge of the edge portion 501 may be in contact with the inner surface 801 of the head body 800.

[0073] The width of the central portion 502 in the x-direction (width direction relative to the nozzle plate 100) is smaller than the width of the edge portion 501 in the x-direction. As shown in Figures 1, 2, and 3, since the central portion 502 is separated from the inner wall of the head body 800, ink can flow towards the nozzle plate 100 through the space between the central portion 502 and the head body 800.

[0074] The upper and lower edges of the central portion 502 may be separated from the inner surface 801 of the head body 800.

[0075] In the storage chamber 810, the ink located below the first filter 410 experiences reduced circulation, making it prone to ink particle sedimentation. This can lead to variations in ink particle density depending on the position of the nozzle 110. As a result, defects such as stains may occur on the display panel formed using the inkjet head 1000 due to variations in the function of the thin film. In this embodiment, the cover plate 500 prevents the incoming ink particles from immediately descending to the nozzle 110.

[0076] The cover plate 500 may, but is not limited to, include metal.

[0077] Depending on the embodiment, the cover plate 500 may be omitted.

[0078] According to this embodiment, by adding a second inlet 330 and a second outlet 340 in addition to the first inlet 310 and first outlet 320, the circulation of ink within the storage chamber 810 can be improved. Therefore, it is possible to prevent uneven variations in the concentration of ink particles caused by settling particles in the space between the cover plate 500 and the head body 800. This prevents uneven settling variations of ink particles within the storage chamber 810 from causing uneven ink concentration depending on the nozzle 110 position, thereby preventing deviations in the function of the thin film on the display panel formed using the inkjet head 1000 and preventing defects such as image smudging. Furthermore, since there is no need to perform unnecessary operations such as ink purging to control the concentration variations of the ink particles 11 of the ink 10, it is possible to prevent waste of ink material and reduce ink material costs.

[0079] The second filter 420 between the second inlet 330 and the storage chamber 810 blocks ink impurities and reduces imbalances in ink circulation in the space between the first filter 410 and the nozzle plate 100.

[0080] By positioning the second inlet 330 above the cover plate 500, it is possible to prevent ink vortices directly above the nozzle plate 100 and to prevent particle sedimentation on the upper part of the cover plate 500.

[0081] An inkjet head according to one embodiment will be described with reference to Figures 5 to 7.

[0082] Figure 5 is a plan view of an inkjet head according to one embodiment, Figure 6 is a cross-sectional view of the inkjet head shown in Figure 5 along the line A1-A2, and Figure 7 is a cross-sectional view of the inkjet head shown in Figure 5 along the line B1-B2.

[0083] The inkjet head 1001 according to this embodiment is almost identical to the inkjet head 1000 according to the embodiment shown in Figures 1 to 4 above, but may further include a first flow control unit 610 and a second flow control unit 620 located in the storage chamber 810 and formed on the bottom surface of the head body 800. The line A1-A2 in Figure 5 is divided into two lines inside the head body 800, with the upper line in Figure 5 passing through the second flow control unit 620 and the lower line passing through the multiple nozzles 110.

[0084] As shown in Figures 5 and 7, the first flow control unit 610 and the second flow control unit 620 do not overlap with the multiple nozzles 110 in the xy plane. However, for convenience, Figure 6 shows the second flow control unit 620 and the multiple nozzles in the same longitudinal section.

[0085] The first flow control unit 610 can be located outside of the nozzle rows 115a and 115d that are located on the edge side of the plurality of nozzle rows 115a, 115b, 115c, and 115d, that is, between the outer nozzle rows 115a and 115d and the inner surface 801 of the head body 800.

[0086] Each first flow control unit 610 may be formed to be long in the direction in which the nozzle rows 115a and 115d are extended, that is, in the y-direction, and may extend adjacent to and along each nozzle row 115a and 115d.

[0087] The cross-sectional structure of the first flow control unit 610 as viewed in the xz plane may be approximately triangular with an upward-pointing shape, but is not limited to this.

[0088] The second flow control unit 620 can be located between two adjacent nozzle rows 115b and 115c, which are located on the inside of the plurality of nozzle rows 115a, 115b, 115c, and 115d. In particular, the second flow control unit 620 can be located between two adjacent nozzle rows 115b and 115c, which are located in the center of the plurality of nozzle rows 115a, 115b, 115c, and 115d. One or more second flow control units 620 can be located between two adjacent nozzle rows 115b and 115c. Figures 5 and 7 show an example in which two second flow control units 620 are located between two adjacent nozzle rows 115b and 115c in the center, but the number of second flow control units 620 is not limited to this.

[0089] Each second flow control unit 620 can be formed to be long in the direction in which the nozzle rows 115b and 115c are extended, that is, in the y-direction (the longitudinal direction of the nozzle plate 100), and can be adjacent to each nozzle row 115b and 115c and extend along the nozzle rows 115b and 115c.

[0090] The cross-sectional structure of the second flow control unit 620, as viewed on the xz plane (the plane along the vertical and width directions of the nozzle plate 100), may be approximately triangular with an upward-pointing shape, but is not limited to this.

[0091] The height of the second flow control unit 620 in the z-direction may be greater than the height of the first flow control unit 610 in the z-direction. The cross-sectional size of the second flow control unit 620 may be larger than the cross-sectional size of the first flow control unit 610.

[0092] The first flow control unit 610, as shown by the S-shaped curved arrow in Figure 7, can prevent ink particles 11 from immediately flowing into the outer nozzle rows 115a and 115d by settling around the cover plate 500. The second flow control unit 620, which is larger than the first flow control unit 610, can obstruct the flow of ink particles 11 around the inner nozzle rows 115b and 115c, as shown by the S-shaped curved arrow in Figure 7, thereby inducing the settling of the particles 11. This improves the situation where the concentration of ink particles 11 is relatively lower in the central region of the nozzle plate 100 than in the edge region of the nozzle plate 100, which is closer to the space between the cover plate 500 and the head body 800. Therefore, the concentration of particles 11 in the ink 10 passing through the multiple nozzles 110 of the nozzle plate 100 can be made more uniform.

[0093] An inkjet head according to one embodiment will be described with reference to Figures 8 to 10.

[0094] Figure 8 is a plan view of an inkjet head according to one embodiment, Figure 9 is a cross-sectional view of the inkjet head shown in Figure 8 along the line A1-A2, and Figure 10 is a cross-sectional view of the inkjet head shown in Figure 8 along the line B1-B2.

[0095] The inkjet head 1002 according to this embodiment is almost identical to the inkjet head 1000 or inkjet head 1001 described above, but it may include a cover plate 510 instead of a cover plate 500.

[0096] The cover plate 510 may contain one or more holes 52 inside. The holes 52 may not overlap with the nozzle 110 in the xy plane. Because the holes 52 do not overlap with the nozzle 110, it is possible to prevent ink particles 11 descending through the holes 52 from immediately settling into the nozzle 110.

[0097] One or more holes 52 can divide the central portion 502 into two or more regions. Figure 8 shows an example in which one hole 52 divides the central portion 502 into two regions.

[0098] As shown by the curved arrow in Figure 10, the ink particles 11 can descend toward the nozzle plate 100 not only through the space between the cover plate 510 and the head body 800, but also through the central hole 52 of the cover plate 510. This improves the situation where the concentration of ink particles 11 is relatively lower in the central region of the nozzle plate 100 than in the edge region of the nozzle plate 100 that is closer to the space between the cover plate 510 and the head body 800. Therefore, the concentration of particles 11 in the ink 10 passing through the multiple nozzles 110 of the nozzle plate 100 can be made more uniform.

[0099] Referring to Figures 9 and 10, the cover plate 510 can have a mesh or screen-like structure. This allows the cover plate 510 to include a plurality of holes 51. Each hole 51 is smaller than the hole 52 that divides the central portion 502 of the cover plate 510 into two. The holes 51 may be larger than or the same size as the ink particles 11. This allows for improved circulation of the ink particles 11 by the cover plate 510.

[0100] In addition, the features of the cover plate 500 of the embodiment described above can also be applied identically to the cover plate 510 of this embodiment.

[0101] An inkjet head according to one embodiment will be described with reference to Figures 11 to 13.

[0102] Figure 11 is a plan view of an inkjet head according to one embodiment, Figure 12 is a cross-sectional view of the inkjet head shown in Figure 11 along the line A1-A2, and Figure 13 is a cross-sectional view of the inkjet head shown in Figure 11 along the line B1-B2.

[0103] The inkjet head 1003 according to this embodiment is almost identical to the inkjet head 1000, inkjet head 1001, or inkjet head 1002 described above, but may further include a third filter 430 and a fourth filter 440.

[0104] The A1-A2 line in Figure 11 does not pass through the third filter 430 or the fourth filter 440, but for ease of understanding, the fourth filter 440 is shown in Figure 12.

[0105] The third filter 430 and the fourth filter 440 are located within the storage chamber 810 and may each extend onto the yz plane (the plane along the vertical and longitudinal directions of the nozzle plate 100). The third filter 430 and the fourth filter 440 are located near the opposing edges (front and rear side walls) of the head body 800 and are separated from the inner surface 801 (front and rear side wall surface) of the head body 800 by a separation distance GP greater than 0. The third filter 430 and the fourth filter 440 may face each other with the cover plate 510 in between.

[0106] Referring to Figures 12 and 13, the third filter 430 and the fourth filter 440 can be extended from the upper region to the lower region of the cover plate 510.

[0107] Unlike the embodiments described above, as shown in Figure 11, the upper and lower ends of the first filter 410 may be separated vertically from the inner surface 801 of the head body 800. This separation distance may be the same as the separation distance GP from the front and rear side walls.

[0108] The third filter 430 and the fourth filter 440 can be connected to at least one of the first filter 410 and the second filter 420. The third filter 430 and the fourth filter 440 can also be connected to the first filter 410 and the second filter 420 to form an inverted cup shape that overlaps and covers the multiple nozzles 110 at the bottom. The connected first filter 410, second filter 420, third filter 430, and fourth filter 440 can combine to form a hexahedron with an open bottom (and right side), but the shape is not limited to this and can also have other forms, such as a dome shape.

[0109] The third filter 430 and the fourth filter 440 may have the same material and function as the first filter 410 or the second filter 420. That is, the third filter 430 and the fourth filter 440 can block impurities other than the ink material particles 11 from the incoming ink, and then allow the ink to pass to the nozzle 110. For this purpose, the third filter 430 and the fourth filter 440 may have pores large enough to allow the ink material particles 11 to pass through, while blocking larger impurities.

[0110] As shown by the straight arrows in Figures 12 and 13, after impurities are removed, the incoming ink can pass through the first filter 410, the second filter 420, the third filter 430, and the fourth filter 440 to move toward the nozzle 110.

[0111] According to this embodiment, in the storage chamber 810, after the ink moves towards the nozzle plate 100 side through the separation interval GP, it passes through the third filter 430 and the fourth filter 440. This reduces the number of particles that stagnate after passing through the first filter 410, thereby further improving the circulation of ink in the storage chamber 810.

[0112] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the claims also fall within the scope of the present invention.

[0113] According to one preferred embodiment, the following applies:

[0114] The background to this matter is as follows (i) to (v).

[0115] (i) In the manufacture of display panels such as organic light-emitting displays (OLEDs) and liquid crystal displays (LCDs), inkjet methods are used or being considered for manufacturing, for example, color filter patterns.

[0116] (ii) Examples of inkjet inks include those in which colored or black pigments, conductive fine particles, quantum dots for light wavelength conversion, organic light-emitting materials, etc., are dispersed in an organic solvent or aqueous solvent together with a curable resin.

[0117] (iii) An inkjet head typically includes an ink reservoir chamber that holds a relatively small amount of ink, and a number of nozzles arranged on the bottom of this reservoir chamber. These nozzles eject ink downwards by expanding and contracting their inner diameter using a piezoelectric element or the like. These nozzles are typically dot-shaped when viewed from above in a plan view and are arranged in multiple rows.

[0118] (iv) In order to arrange a large number of inkjet heads, the inkjet heads and the ink storage chambers inside them are generally shaped like rectangular parallelepipeds, with nozzles formed to penetrate their bottom walls. Furthermore, in order to maintain a consistent and uniform state of ink in the ink storage chambers, ink is made to flow from an ink inlet located at one end of the inkjet head (the longitudinal end) to an ink outlet located at the other end of the inkjet head, thereby circulating ink between a relatively large-capacity ink tank and the inside of each inkjet head.

[0119] (v) To prevent foreign particles from being sent to the nozzles of the inkjet head, it has been proposed to place a plate-shaped filter in the ink storage chamber. In particular, when the ink storage chamber is divided into an upper upstream liquid chamber and a lower downstream liquid chamber by a horizontal plate-shaped filter, the following specific proposal has been made to prevent the generation of air bubbles in the downstream chamber (Patent Document 1). The ink storage chamber is equipped with two outlets: one from the upstream liquid chamber and another from the downstream liquid chamber. • A horizontal plate is provided in the liquid chamber on the downstream side to cover the nozzle arrangement located in the center of its width. • A component is provided to narrow the width of the liquid chamber on the downstream side.

[0120] This case is based on the discovery of the following problem in one embodiment. Ink particles dispersed in the ink, such as pigments, conductive fine particles, or particles containing these and curable resins, may experience uneven distribution concentrations in the ink storage chamber due to phenomena such as localized sedimentation.

[0121] In a preferred embodiment, in order to solve the above problems, the following A1-A2 or A1-A3 may be used, where A4 may be used instead of A3. In addition to these, the following A5, A5-A6, A5-A7, A5-A8 or A5-A9 may be used.

[0122] One end (the longitudinal end) of the A1 inkjet head (1000) is provided with a first inlet (310) that allows ink to flow vertically downward (in the direction of discharge of the nozzle 110) into the ink storage chamber (storage chamber 810), and a second inlet (330) that allows ink to flow longitudinally inward into the inkjet head (1000) into the ink storage chamber (storage chamber 810). (See Figure 3, etc.)

[0123] The other end (longitudinal end) of the A2 inkjet head (1000) is provided with a first outlet (320) that causes ink to flow out vertically upward (opposite to the discharge direction of the nozzle 110) from the ink storage chamber (storage chamber 810), and a second outlet (340) that causes ink to flow out longitudinally outward from the inkjet head (1000). (See Figure 3, etc.)

[0124] A horizontal plate-shaped first filter (410) is positioned to divide the A3 ink storage chamber (storage chamber 810) vertically, and is positioned higher than the upper end of the first inlet (310) and the upper end of the second outlet (340). A vertical plate-shaped second filter (420) is installed at the first inlet (310). (See Figures 3-4, etc.)

[0125] A4 In the same configuration as A3 above, the horizontal plate-shaped first filter (410) is omitted at both edges in the width direction of the ink storage chamber (storage chamber 810), and both edges are combined with the vertical plate-shaped third filter (410) and the third filter (410), so that the cross-section in the width direction is U-shaped. (Figure 13)

[0126] A horizontal baffle plate (cover plate 500, 510) is placed between the bottom wall (including nozzle plate 100 and piezoelectric element 200) of the ink storage chamber (storage chamber 810), through which the A5 nozzles (110) are arranged, and the horizontal plate-shaped first filter (410). This is referred to as A5-1 or A5-2. (Figures 4 and 7, and Figures 10 and 13)

[0127] A5-1 These baffles (cover plates 500, 510) are omitted only near the edges of the ink storage chamber (storage chamber 810) in the width direction (Figures 4 and 7). A5-2 The ink is omitted only near the edges on both sides in the width direction of the ink storage chamber (storage chamber 810) and near the center line of the ink storage chamber (storage chamber 810) (Figures 10 and 13).

[0128] The A6 nozzle (110) is omitted near the center line of the ink storage chamber (storage chamber 810), and multiple rows of nozzles (110) are arranged on either side of this point. (Figures 1-2 and 4, etc.)

[0129] A7 In particular, based on the above A5-1, the bottom wall of the ink storage chamber (storage chamber 810) is provided with ridge-like protrusions (first flow control unit 610) that perform a baffle action, extending in the longitudinal direction of the ink storage chamber (storage chamber 810) on the outside in the width direction of the row of nozzles (110). (Figures 5-7)

[0130] A8 In particular, based on the above A5-1 and A6, the bottom wall of the ink storage chamber (storage chamber 810) is provided with baffle-like projections (second flow control unit 620) that extend in the longitudinal direction of the ink storage chamber (storage chamber 810) along both edges of the area near the center line of the ink storage chamber (storage chamber 810). (Figures 5-7)

[0131] A9 The above-mentioned striated projections (first flow control unit 610, second flow control unit 620) are tapered (wedge-shaped) toward the upward. Preferably, the striated projection located near the center line (second flow control unit 620) has a larger projection dimension (height) than the striated projection located on the outside in the width direction of the row of nozzles (110) (first flow control unit 610). (Figures 5-7) [Explanation of symbols]

[0132] 10: Ink 11: Particles 100: Nozzle plate 110: Nozzle 115a, 115b, 115c, 115d: Nozzle rows 200: Piezoelectric element 310, 330: Inlet 310p, 330p: Inflow pipe 320, 340: Outlet 320p, 340p: Outflow tube 410, 420, 430, 440: Filters 500, 510: Cover plate 610, 620: Flow Control Unit 800: Head body 801: Inner surface 810: Storage Room 1000, 1001, 1002, 1003: Inkjet heads

Claims

1. A print head body having a storage chamber capable of storing ink, A first inlet pipe and a second inlet pipe are connected to the head body and allow ink to flow in from different directions. A first outlet pipe and a second outlet pipe are connected to the head body and are capable of discharging ink in different directions from each other, and A nozzle plate located at the bottom of the head body, which includes multiple nozzles. Includes, The first inlet pipe and the second inlet pipe are located on the side of the first edge of the head body, The first outflow pipe and the second outflow pipe are located on the side of the second edge of the head body facing the first edge, The first inlet pipe and the first outlet pipe are formed in a first direction, The second inlet pipe and the second outlet pipe are formed in a second direction perpendicular to the first direction, It includes a first filter and a second filter located inside the storage chamber and extending in different directions from each other, The first filter extends parallel to the nozzle plate and overlaps with the first inlet pipe and the first outlet pipe on the first plane. The second filter is located inside the second inlet pipe and overlaps with the second inlet pipe on a second plane in a direction different from that of the first plane. The first filter is located below the first inlet pipe and the first outlet pipe, with reference to the nozzle plate, and above the second inlet pipe and the second outlet pipe. The storage chamber further includes a cover plate located between the first filter and the nozzle plate, The cover plate is positioned below the second inlet pipe, with reference to the nozzle plate, and overlaps with the plurality of nozzles on the first plane. The cover plate includes a pair of edges adjacent to the first edge and the second edge of the head body on the first plane, and a central portion located between the pair of edges and connected to the pair of edges. If the third direction is defined as the direction perpendicular to the first and second directions, then the width of the central portion in the third direction is smaller than the width of the edge portion in the third direction. Inkjet head.

2. The aforementioned edge portion is in contact with the inner surface of the head body, The central portion is separated from the inner surface of the head body. The inkjet head according to claim 1.

3. The inkjet head according to claim 1, wherein the cover plate is arranged to connect the inlet and outlet of the second inlet pipe and the second outlet pipe, which are respectively connected to the storage chamber.

4. The inkjet head according to claim 1, wherein the cover plate is positioned at the end of the second inlet (330) so as to be in contact with the storage chamber.

5. The inkjet head according to claim 1, further comprising a third filter located in the storage chamber and separated from the inner surface of the head body.

6. The third filter has an edge that is connected to the edge of the first filter. The inkjet head according to claim 5.

7. A print head having a storage chamber capable of storing ink, A first inlet pipe and a second inlet pipe are connected to the head body and allow ink to flow in from different directions. A first outlet pipe and a second outlet pipe are connected to the head body and are capable of discharging ink in different directions from each other, and A nozzle plate located at the bottom of the head body, which includes multiple nozzles. Includes, The first inlet pipe and the second inlet pipe are located on the side of the first edge of the head body, The first outflow pipe and the second outflow pipe are located on the side of the second edge of the head body facing the first edge, The first inlet pipe and the first outlet pipe are formed in a first direction, The second inlet pipe and the second outlet pipe are formed in a second direction perpendicular to the first direction, It includes a first filter and a second filter located inside the storage chamber and extending in different directions from each other, The first filter extends parallel to the nozzle plate and overlaps with the first inlet pipe and the first outlet pipe on the first plane. The second filter is located inside the second inlet pipe and overlaps with the second inlet pipe on a second plane in a direction different from that of the first plane. The first filter is located below the first inlet pipe and the first outlet pipe, with reference to the nozzle plate, and above the second inlet pipe and the second outlet pipe. The storage chamber further includes a cover plate located between the first filter and the nozzle plate, The cover plate is positioned below the second inlet pipe, with reference to the nozzle plate, and overlaps with the plurality of nozzles on the first plane. The cover plate has one or more holes inside, An inkjet head including a first hole that does not overlap with the plurality of nozzles, and a plurality of second holes that are smaller in size than the first hole.

8. The inkjet head according to claim 7, wherein the cover plate has a mesh or net-like structure to form the second hole.

9. A print head having a storage chamber capable of storing ink, A first inlet pipe and a second inlet pipe are connected to the head body and allow ink to flow in from different directions. A first outlet pipe and a second outlet pipe are connected to the head body and are capable of discharging ink in different directions from each other, and A nozzle plate located at the bottom of the head body, which includes multiple nozzles. Includes, The first inlet pipe and the second inlet pipe are located on the side of the first edge of the head body, The first outflow pipe and the second outflow pipe are located on the side of the second edge of the head body facing the first edge, The first inlet pipe and the first outlet pipe are formed in a first direction, The second inlet pipe and the second outlet pipe are formed in a second direction perpendicular to the first direction, It includes a first filter and a second filter located inside the storage chamber and extending in different directions from each other, The first filter extends parallel to the nozzle plate and overlaps with the first inlet pipe and the first outlet pipe on the first plane. The second filter is located inside the second inlet pipe and overlaps with the second inlet pipe on a second plane in a direction different from that of the first plane. The first filter is located below the first inlet pipe and the first outlet pipe, with reference to the nozzle plate, and above the second inlet pipe and the second outlet pipe. The storage chamber further includes a cover plate located between the first filter and the nozzle plate, The cover plate is positioned below the second inlet pipe, with reference to the nozzle plate, and overlaps with the plurality of nozzles on the first plane. It includes a first flow control unit located on the bottom surface of the head body and not overlapping with the plurality of nozzles on the first plane, The first flow control unit is located between the outer nozzle row and the inner surface of the head body, among the plurality of nozzle rows in which the plurality of nozzles are formed. The first flow control unit extends along the nozzle row of the outer casing, It further includes a second flow control unit located on the bottom surface of the head body and not overlapping with the plurality of nozzles on the first plane, The second flow control unit is located on the inside of the plurality of nozzle rows and between two adjacent nozzle rows. The second flow control unit extends along the inner nozzle row. Inkjet head.

10. The first flow control unit and the second flow control unit have an upwardly pointed shape, The height of the second flow control unit is higher than the height of the first flow control unit. The inkjet head according to claim 9.

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