Inkjet printing apparatus

Abstract

The present application relates to an inkjet printing apparatus. The inkjet printing apparatus includes a lane plate in which a head chamber is provided, and a plurality of nozzle plates disposed below the lane plate, the plurality of nozzle plates including nozzles fluidly connected to the head chamber. The plurality of nozzle plates are stacked on each other, and the nozzles of the plurality of nozzle plates are formed by a plurality of through-holes passing through the plurality of nozzle plates and overlapping each other.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0090812, filed on July 22, 2020, which is incorporated herein by reference for all purposes as fully set forth herein. Technical Field

[0003] Embodiments of the present invention generally relate to inkjet printing apparatus, and more specifically, to inkjet printing apparatus comprising a head unit having stacked nozzle plates. Background Technology

[0004] Inkjet printing is a technique that uses colored ink to create images by spraying ink onto predetermined areas separated by partitions. Recently, inkjet printing has been widely used in the manufacturing processes of display devices, such as organic light-emitting diode (OLED) displays and liquid crystal display (LCD) displays. When printing patterns for display devices using inkjet printing, compared to deposition processes, components can be produced with significantly less material, and costs can be greatly reduced due to the simplification of the manufacturing process.

[0005] However, when ink stains or partial blockages occur in the nozzles through which ink is ejected, the straightness of the ink cannot be guaranteed, and the reproducibility of the ink impact point may deteriorate. In this case, defects may occur where the pattern cannot be printed in the precise shape. Furthermore, productivity may decrease due to the maintenance work required to remove ink stains or blockages from the nozzles.

[0006] The information disclosed in this background section is only for understanding the background technology of the inventive concept, and therefore may contain information that does not constitute prior art. Summary of the Invention

[0007] The applicant discovered that when manufacturing display devices using inkjet printing equipment including a head unit with nozzles via inkjet printing processes, the nozzles of the head unit of the inkjet printing equipment may be prone to clogging, which may degrade the reproducibility of the inkjet printing equipment and increase the maintenance costs of the inkjet printing equipment.

[0008] Inkjet printing equipment having a head unit for manufacturing a display device constructed according to the principles and implementation of the present invention can improve production efficiency by increasing the replacement cycle of the head unit of the inkjet printing equipment. For example, the inkjet printing equipment includes stacked nozzle plates of head units, and the stacked nozzle plates can be easily repaired by disassembling and removing defective nozzle plates from the stacked nozzle plates. Therefore, the replacement time of the head unit can be shortened, thereby improving the production efficiency of the inkjet printing equipment.

[0009] According to one aspect of the invention, an inkjet printing apparatus includes: a channel plate having a head chamber disposed therein; and a plurality of nozzle plates disposed below the channel plate, the plurality of nozzle plates including nozzles in fluid communication with the head chamber, wherein: the plurality of nozzle plates are stacked on top of each other, and the nozzles of the plurality of nozzle plates are formed by a plurality of through holes passing through the plurality of nozzle plates and overlapping each other.

[0010] The multiple nozzle plates may include protrusions extending outward from the side surface of at least one of the multiple nozzle plates.

[0011] A waterproof layer may be provided on the bottom surface of each of the multiple nozzle plates.

[0012] An adhesive layer may be provided between the waterproof layer and the nozzle plates below the waterproof layer in the multiple nozzle plates.

[0013] The adhesive strength between the adhesive layer and the upper surface of each of the multiple nozzle plates can be greater than the adhesive strength between the adhesive layer and the waterproof layer.

[0014] Each of the multiple through holes in the multiple nozzle plates may include an upper inner surface having a first width and a lower inner surface having a second width less than the first width.

[0015] The plurality of nozzle plates may include a first nozzle plate and a second nozzle plate disposed on the first nozzle plate, and the first width of the through hole of the first nozzle plate may be greater than the first width of the through hole of the second nozzle plate.

[0016] The plurality of nozzle plates may include: a first nozzle plate; and a second nozzle plate disposed on the first nozzle plate.

[0017] The first waterproof layer can be disposed on the bottom surface of the first nozzle plate, and the second waterproof layer can be disposed on the bottom surface of the second nozzle plate.

[0018] Each of the multiple nozzle plates may include multiple sub-nozzle plates arranged in one direction.

[0019] It will be understood that both the foregoing overview and the following detailed description are exemplary and illustrative, and are intended to provide further explanation of the claimed invention. Attached Figure Description

[0020] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to illustrate the inventive concept.

[0021] Figure 1 This is a plan view of an embodiment of a display device constructed according to the principles of the present invention.

[0022] Figure 2 yes Figure 1 A cross-sectional view of the display device.

[0023] Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 It is shown Figure 1 A cross-sectional view of a part of the manufacturing process of a display device.

[0024] Figure 8 This is a perspective view of an embodiment of an inkjet printing device constructed according to the principles of the present invention.

[0025] Figure 9 yes Figure 8 A three-dimensional view of the head unit of an inkjet printing machine.

[0026] Figure 10 yes Figure 8 A bottom view of the head unit of an inkjet printing machine.

[0027] Figure 11 It is along Figure 10 A sectional view taken from line I-I'.

[0028] Figure 12 This is an inspection demonstrating the principles of the present invention. Figure 8 A flowchart of the process of inkjet printing equipment.

[0029] Figure 13 and Figure 14 Is using Figure 8 The inkjet printing equipment has formed a three-dimensional image of the substrate with impact points on it.

[0030] Figure 15 , Figure 16 and Figure 17 This is a cross-sectional view showing the process of removing the nozzle plate from the contaminated head unit.

[0031] Figure 18 yes Figure 8 A perspective view of another embodiment of the nozzle plate of the head unit of an inkjet printing device.

[0032] Figure 19 yes Figure 8 A perspective view of another embodiment of the nozzle plate of the head unit of an inkjet printing device.

[0033] Figure 20 yes Figure 8 A perspective view of another embodiment of the nozzle plate of the head unit of an inkjet printing device.

[0034] Figure 21 yes Figure 8 A cross-sectional view of another embodiment of the nozzle plate of the head unit of an inkjet printing device.

[0035] Figure 22 yes Figure 8 A cross-sectional view of another embodiment of the nozzle plate of the head unit of an inkjet printing device.

[0036] Figure 23 yes Figure 8 A cross-sectional view of another embodiment of the nozzle plate of the head unit of an inkjet printing device. Detailed Implementation

[0037] In the following description, numerous specific details are set forth for illustrative purposes to provide a thorough understanding of various embodiments or implementations of the invention. As used herein, “implementation” and “method” are interchangeable terms, referring to non-limiting examples of apparatus or methods of one or more of the inventive concepts disclosed herein. However, it will be apparent, however, that various embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other examples, well-known structures and apparatuses are shown in block diagram form to avoid unnecessarily obscuring the various embodiments. Furthermore, the various embodiments may be different, but are not necessarily exclusive. For example, a particular shape, configuration, and characteristic of an embodiment may be used or implemented in another embodiment without departing from the inventive concept.

[0038] Unless otherwise stated, the embodiments shown should be understood as exemplary features providing different details of some ways in which the inventive concept can be implemented in practice. Therefore, unless otherwise stated, features, components, modules, layers, films, panels, regions and / or aspects (hereinafter individually or collectively referred to as “elements”) of various embodiments may be combined, separated, interchanged and / or rearranged without departing from the inventive concept.

[0039] The use of crosshairs and / or shading in accompanying drawings is generally to clarify the boundaries between adjacent elements. Therefore, unless otherwise stated, the presence or absence of crosshairs or shading does not convey or indicate any preference or requirement for particular materials, material properties, dimensions, scale, commonalities between illustrated elements, and / or any other characteristics, properties, etc., of the elements. Furthermore, in the accompanying drawings, the dimensions and relative dimensions of elements may be exaggerated for clarity and / or descriptive purposes. When embodiments can be implemented differently, the specific order of processes may be performed differently than the order described. For example, two consecutively described processes may be performed substantially simultaneously, or in the reverse order of their description. Moreover, the same reference numerals denote the same elements.

[0040] When an element, such as a layer, is referred to as being "on," "connected to," or "attached to" another element or layer, it may be directly on, directly connected to, or attached to the other element or layer, or there may be an intermediate element or layer. However, when an element or layer is referred to as being "directly on," "directly connected to," or "directly attached to" another element or layer, there is no intermediate element or layer. Therefore, the term "connection" can refer to a physical connection, electrical connection, and / or fluid connection, with or without an intermediate element. Furthermore, the D1, D2, and D3 axes are not limited to the three axes of a Cartesian coordinate system (such as the x, y, and z axes) and can be interpreted in a broader sense. For example, the D1, D2, and D3 axes can be perpendicular to each other, or they can represent different directions that are not perpendicular to each other. For the purposes of this disclosure, "at least one of X, Y, and Z" and "at least one selected from the group consisting of X, Y, and Z" can be interpreted as only X, only Y, only Z, or any combination of two or more of X, Y, and Z, such as XYZ, XYY, YZ, and ZZ. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0041] Although the terms “first,” “second,” etc., may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Therefore, without departing from the teachings of this disclosure, the first element discussed below may be referred to as the second element.

[0042] Spatial relative terms such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” and “side” (e.g., as in “sidewall”) may be used herein for descriptive purposes and thus to describe the relationship of one element to another(s) as shown in the accompanying drawings. In addition to the orientations depicted in the drawings, spatial relative terms are intended to cover different orientations of the device in use, operation, and / or manufacture. For example, if the device in the drawings is flipped, an element described as “below” or “under” other elements or features will then be oriented “above” other elements or features. Thus, the exemplary term “below” can cover both above and below orientations. Furthermore, the device may be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and thus the spatial relative descriptive terms used herein shall be interpreted accordingly.

[0043] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, as used herein. Furthermore, when used in this specification, the terms “comprising,” “including,” “including,” and / or “comprising” indicate the presence of stated features, integrals, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. It should also be noted that, as used herein, the terms “substantially,” “about,” and other similar terms are used as approximate terms rather than terms of degree, and are therefore used to allow for inherent deviations in measurements, calculated values, and / or provided values ​​that will be recognized by those skilled in the art.

[0044] Various embodiments are described herein with reference to cross-sectional and / or exploded views as schematic diagrams of idealized embodiments and / or intermediate structures. Thus, deviations from the illustrated shapes due to, for example, manufacturing techniques and / or tolerances will be expected. Therefore, the embodiments disclosed herein should not necessarily be construed as limited to the shape of the specific regions shown, but rather include deviations in shape caused, for example, by manufacturing processes. In this way, the regions shown in the figures may be schematic in nature, and the shapes of these regions may not reflect the actual shapes of the regions of the device, and are therefore not necessarily intended to be limiting.

[0045] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms, such as those defined in commonly used dictionaries, shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0046] Throughout the specification, the same reference numerals denote the same parts.

[0047] In the following description, embodiments will be described with reference to the accompanying drawings.

[0048] Figure 1 This is a plan view of a display device according to an embodiment.

[0049] Display device 1 can represent any electronic device having a display screen. Examples of display device 1 may include televisions, laptops, monitors, billboards, mobile phones, smartphones, tablet PCs, electronic watches, smartwatches, watch phones, mobile communication terminals, electronic laptops, e-books, portable multimedia players (PMPs), navigation devices, game consoles, digital cameras, Internet of Things devices, etc., that provide a display screen. Figure 1 The display device 1 shown is a television. The display device 1 can have high resolution or ultra-high resolution, such as HD, UHD, 4K, and 8K. However, the implementation is not limited to this.

[0050] The display device 1 may include various patterns for transmitting signals or changing the wavelength of light at each location. The patterns on the display device 1 are formed through a patterning process. The patterning process may include optical processing, inkjet printing, etc. Some of the patterns may be printed using inkjet printing equipment (e.g., Figure 8 The 1000) are formed by inkjet printing. The following embodiment shows a display device 1 in which some patterns are formed by inkjet printing.

[0051] The display device 1 can be classified in different ways depending on the display method. For example, the display device 1 can be classified as an organic light-emitting display (organic LED) device, an inorganic light-emitting display (inorganic LED) device, a quantum dot light-emitting display (QED) device, a micron LED display device, a nano LED display device, a plasma display device (PDP), a field emission display (FED) device, a cathode ray tube (CRT) display device, a liquid crystal display (LCD) device, an electrophoretic display (EPD) device, etc. In the following description, an organic light-emitting display device will be used as an example of the display device 1, and unless special distinction is required, the organic light-emitting display device applied to the embodiments will be simply referred to as the display device 1. However, the embodiments are not limited thereto. For example, other display devices mentioned above or known in the art can be applied to the embodiments.

[0052] Reference Figure 1 The display device 1 may include a display area DPA and a non-display area NDA.

[0053] The display area DPA may include multiple pixels PX. The multiple pixels PX can be arranged in a matrix. In a planar view, the shape of each pixel PX can be rectangular or square. However, the implementation is not limited to this. For example, each pixel PX can have a rhombus shape, with each side inclined relative to one side of the display device 1. Pixel PX can include pixels PX of various colors. For example, pixel PX can include a first color pixel PX of red, a second color pixel PX of green, and a third color pixel PX of blue, but the implementation is not limited to this. The colored pixels PX can be arranged alternately in a stripe type or a pentile type.

[0054] The non-display area NDA can be disposed around the display area DPA. The non-display area NDA can completely or partially surround the display area DPA. The display area DPA can have a rectangular shape, and the non-display area NDA can be disposed adjacent to the four sides of the display area DPA. The non-display area NDA can form the frame of the display device 1.

[0055] In the non-display area NDA, a driving circuit or driving element for driving the display area DPA can be provided. In an embodiment, the pad portion provided on the display substrate of the display device 1 can be provided at a position that is aligned with the first long side of the display device 1 (e.g., ...). Figure 1 The first non-display area NDA, adjacent to the lower side of the display device 1, and the second long side (e.g., the lower side of the display device 1) are arranged to be adjacent to the lower side of the display device 1. Figure 1 The external device EXD can be mounted on the pad electrode of the pad portion. The external device EXD may include, for example, a connection film, a printed circuit board, a driver integrated circuit (DIC), a connector, a wiring connection film, etc. The scan driver SDR formed directly on the display substrate of the display device 1 can be disposed at the first short side of the display device 1 (e.g., the upper side of the display). Figure 1 In the third non-display area NDA adjacent to the left side of the image.

[0056] Figure 2 This is a cross-sectional view of a display device according to an embodiment.

[0057] Reference Figure 2 The display device 1 may include a first display substrate 10, a second display substrate 20 facing the first display substrate 10, and a filler layer 30 interposed between the first display substrate 10 and the second display substrate 20. For example, the filler layer 30 may bond the first display substrate 10 to the second display substrate 20.

[0058] The first display substrate 10 may include a first substrate 11, a pixel electrode PXE disposed for each pixel PX, a pixel defining layer PDL disposed along the boundary of the pixel PX, a light emitting layer EML positioned in an opening exposed by the pixel defining layer PDL and disposed on the pixel electrode PXE, a common electrode CME disposed on the light emitting layer EML and the pixel defining layer PDL and configured to span multiple pixels PX, and a packaging structure ECL disposed on the common electrode CME.

[0059] The pixel defining layer (PDL) may overlap with the edge portion of the pixel electrode (PXE). The emissive layer (EML) comprises an organic light-emitting material. Regardless of the type of pixel (PX), the organic light-emitting material of the emissive layer (EML) can emit the same color. For example, the emissive layer (EML) can emit blue light in all of the red, green, and blue pixel (PX). However, the implementation is not limited to this. The pixel defining layer (PDL) may include an opening that exposes the pixel electrode (PXE). The light-blocking region (BA) and the light-transmitting region (TA) may be defined by the pixel defining layer (PDL) and the opening of the pixel defining layer (PDL), respectively.

[0060] The encapsulation structure ECL may include at least one thin-film encapsulation layer. For example, the thin-film encapsulation layer may include a first inorganic layer 17, an organic layer 18, and a second inorganic layer 19.

[0061] The second display substrate 20 may include a second substrate 21, a light blocking member BML disposed on one surface of the second substrate 21 facing the first substrate 11, a color filter layer CFL disposed on one surface of the second substrate 21 in an opening defined by the light blocking member BML, a first capping layer 22 disposed on the color filter layer CFL and the light blocking member BML, a partition wall PTL disposed on the first capping layer 22 and overlapping the light blocking member BML, a wavelength conversion layer WCL and a light transmission layer TPL disposed in the space surrounded by the partition wall PTL, and a second capping layer 23 disposed on the wavelength conversion layer WCL, the light transmission layer TPL and the partition wall PTL.

[0062] The light-blocking member BML can be disposed in the light-blocking region BA to overlap with the pixel defining layer PDL, and includes an opening that exposes one surface of the second substrate 21 while overlapping with the light-transmitting region TA.

[0063] The color filter layer CFL may include a first color filter layer CFL1 disposed in a first color pixel PX, a second color filter layer CFL2 disposed in a second color pixel PX, and a third color filter layer CFL3 disposed in a third color pixel PX. For example, the first color filter layer CFL1 may be a red (R) color filter layer, the second color filter layer CFL2 may be a green (G) color filter layer, and the third color filter layer CFL3 may be a blue (B) color filter layer.

[0064] The wavelength conversion layer WCL may include a first wavelength conversion pattern WCL1 disposed in a first color pixel PX and a second wavelength conversion pattern WCL2 disposed in a second color pixel PX. The light transmission layer TPL may be disposed in a third color pixel PX.

[0065] The first wavelength conversion pattern WCL1 may include a first base resin BRS1 and a first wavelength conversion material WCP1 disposed in the first base resin BRS1. The second wavelength conversion pattern WCL2 may include a second base resin BRS2 and a second wavelength conversion material WCP2 disposed in the second base resin BRS2. The light transmission layer TPL may include a third base resin BRS3 and a scatterer SCP disposed in the third base resin BRS3.

[0066] The first base resin BRS1, the second base resin BRS2, ​​and the third base resin BRS3 may comprise light-transmitting organic materials. For example, the first base resin BRS1, the second base resin BRS2, ​​and the third base resin BRS3 may comprise epoxy resin, acrylic resin, cardo resin, imide resin, etc. The first base resin BRS1, the second base resin BRS2, ​​and the third base resin BRS3 may be formed from the same material, but the implementation is not limited thereto.

[0067] The scattering SCP can be metal oxide particles or organic particles. Examples of metal oxides can include titanium oxide (TiO2), zirconium oxide (ZrO2), aluminum oxide (Al2O3), indium oxide (In2O3), zinc oxide (ZnO), tin oxide (SnO2), etc. Examples of organic particle materials can include acrylic resins and urethane resins, etc.

[0068] The first wavelength conversion material WCP1 can convert third-color light into first-color light, and the second wavelength conversion material WCP2 can convert third-color light into second-color light. The first wavelength conversion material WCP1 and the second wavelength conversion material WCP2 can be quantum dots, quantum rods, phosphors, etc. Examples of quantum dots can include group IV compound nanocrystals, group II-VI compound nanocrystals, group III-V compound nanocrystals, group IV-VI compound nanocrystals, and combinations thereof. The first wavelength conversion pattern WCL1 and the second wavelength conversion pattern WCL2 can also include a scatterer SCP for improving wavelength conversion efficiency.

[0069] A light-transmitting layer (TPL) located in the third-color pixel (PX) transmits third-color light emitted from the emissive layer (EML) while maintaining the light's wavelength. The scattering component (SCP) of the TPL can be used to control the emission path of light passing through the TPL. The TPL may not include wavelength conversion material.

[0070] A filler layer 30 may be disposed between the first display substrate 10 and the second display substrate 20. The filler layer 30 may fill the space between the first display substrate 10 and the second display substrate 20, and may bond the first display substrate 10 to the second display substrate 20. The filler layer 30 may be disposed between the encapsulation structure ECL of the first display substrate 10 and the second capping layer 23 of the second display substrate 20.

[0071] As described above, in display device 1, the pixel electrode PXE, pixel defining layer PDL, light-emitting layer EML, light-blocking member BML, color filter layer CFL, spacer wall PTL, wavelength conversion layer WCL, and light-transmitting layer TPL have specific pattern shapes. To form such components, optical processing or inkjet processing can be used. Hereinafter, the patterning process will be described in detail using the manufacturing process of the second display substrate 20 according to an embodiment.

[0072] Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 This is a cross-sectional view showing a portion of the manufacturing process of the display device according to an embodiment, and schematically showing the manufacturing process of the second display substrate 20.

[0073] First, refer to Figure 3 A light-blocking member BML can be formed on one surface of the second substrate 21. For example, the light-blocking member BML can be patterned by an exposure / development process or a photolithography process after coating with a light-blocking material. The light-blocking member BML can be formed with a grid pattern on one surface of the second substrate 21.

[0074] Next, refer to Figure 4 A color filter layer CFL can be formed on one surface of the second substrate 21, and the color filter layer CFL can be disposed (e.g., in the horizontal direction) between the light blocking members BML. The color filter layer CFL can be formed in each overlapping region of the light transmission region TA. The color filter layer CFL can be patterned by an exposure / development process or a photolithography process, or it can be printed using an inkjet printing device (e.g., Figure 8 The 1000) were patterned.

[0075] Subsequently, referring to Figure 5 A first capping layer 22 is formed, covering the color filter layer CFL and the light-blocking member BML, and a partition wall PTL is formed in the region overlapping with the first light-blocking region BA1, the second light-blocking region BA2, and the third light-blocking region BA3. The partition wall PTL can be patterned by, for example, an exposure / development process or a photolithography process.

[0076] Subsequently, a wavelength conversion layer (WCL) and a light transmission layer (TPL) are formed in the space surrounded by the partition wall (PTL). In this embodiment, an inkjet printing apparatus 1000 can be used to form the wavelength conversion layer (WCL) and the light transmission layer (TPL).

[0077] For example, in Figure 5 After the steps shown, refer to Figure 6 The first wavelength conversion pattern WCL1 can be formed by sputtering ink onto the first light-transmitting region TA1 using an inkjet printing apparatus 1000. The first wavelength conversion pattern WCL1 can be formed within the first light-transmitting region TA1 surrounded by a partition wall PTL. The first wavelength conversion pattern WCL1 can be formed by sputtering ink onto the first light-transmitting region TA1 via the nozzle of the inkjet printing apparatus 1000.

[0078] Next, refer to Figure 7 The second wavelength conversion pattern WCL2 can be formed by sputtering ink onto the second light-transmitting region TA2 using inkjet printing equipment 1000. The second wavelength conversion pattern WCL2 can be formed within the second light-transmitting region TA2 surrounded by a partition wall PTL. The second wavelength conversion pattern WCL2 can be formed by sputtering ink onto the second light-transmitting region TA2 via a nozzle or inkjet printhead (different from the nozzle or inkjet printhead used to form the first wavelength conversion pattern WCL1). In another embodiment, the second wavelength conversion pattern WCL2 can be formed using an inkjet printing equipment different from the inkjet printing equipment 1000 used to form the first wavelength conversion pattern WCL1.

[0079] For example, the process for forming the light-transmitting layer TPL is similar to the process for forming the first wavelength conversion pattern WCL1 and the second wavelength conversion pattern WCL2. The light-transmitting layer TPL can be formed in a third light-transmitting region TA3 surrounded by a partition wall PTL. The light-transmitting layer TPL can be formed by sputtering ink onto the third light-transmitting region TA3 through a nozzle different from the nozzles used to form the first wavelength conversion pattern WCL1 and the second wavelength conversion pattern WCL2.

[0080] The inkjet printing equipment 1000 described above will be described in detail below.

[0081] Figure 8 This is a perspective view showing an inkjet printing apparatus according to an embodiment.

[0082] Reference Figure 8 According to the embodiments, the inkjet printing apparatus 1000 may include a base frame 130, a stage 150, a stage moving unit 160, printhead moving units 320, 330 and 340, and a head unit 700.

[0083] Stage 150 can be mounted on base frame 130. Stage 150 provides space for placing target substrate SUB. For example, the target substrate SUB to be subjected to a printing process can be mounted on the top surface of stage 150. A substrate aligner can be mounted above stage 150 to align the target substrate SUB. The substrate aligner can be made of quartz or ceramic material and can be configured as an electrostatic chuck, but the implementation is not limited to this.

[0084] Stage 150 can be made of a transparent or translucent material capable of transmitting light or an opaque material capable of reflecting light. The overall planar shape of stage 150 can be similar to (or substantially equivalent to) the planar shape of the target substrate SUB. For example, when the target substrate SUB has a rectangular shape, the overall shape of stage 150 can be rectangular, and when the target substrate SUB has a circular shape, the overall shape of stage 150 can be circular. In the accompanying drawings, stage 150 is shown with a rectangular shape, wherein the longer side is disposed in the second direction D2, and the shorter side is disposed in the first direction D1.

[0085] The stage 150 can be fixed to the stage moving unit 160 and can move together with the stage moving unit 160. The stage moving unit 160 can be mounted on the base frame 130 and can move on the base frame 130 along the first direction D1. When the stage moving unit 160 is provided, the second horizontal moving unit 320 for moving the head unit 700 in the first direction D1 can be omitted. A detailed description of this will be given later.

[0086] The head unit 700 may be positioned above the stage 150 (e.g., on a third-party D3). The head unit 700 can print ink on the target substrate SUB. The inkjet printing apparatus 1000 may also include an ink supply unit (such as an ink cartridge), and the head unit 700 can sputter (or jet) ink supplied from the ink supply unit onto the target substrate SUB.

[0087] Inks can be supplied in a solution state. Inks may include, for example, a solvent and an organic material contained within the solvent. The organic material may be dispersed in the solvent. The organic material may be as described above. Figure 2 The description includes the base resin, scatterer, and wavelength conversion material. After solvent removal, the organic material can ultimately remain on the target substrate (SUB). The solvent can be a material that evaporates or volatilizes at room temperature or by heating. Solvents can include acetone, water, alcohol, toluene, etc.

[0088] The head unit 700 can be mounted on the support unit 310 and spaced a predetermined distance from the stage 150. The support unit 310 may include a horizontal support portion 311 extending in a horizontal direction (e.g., a first direction D1 or a second direction D2) and a vertical support portion 312 connected to the horizontal support portion 311 and extending in a vertical direction (e.g., a third direction D3). The extension direction of the horizontal support portion 311 may be the same as the second direction D2, which is the direction of the long side of the stage 150. The end of the vertical support portion 312 may be placed on the base frame 130.

[0089] The distance between the head unit 700 and the stage 150 can be adjusted by the height of the support unit 310. When the target substrate SUB is placed on the stage 150, the distance between the head unit 700 and the stage 150 can be adjusted within a range that ensures processing space by setting the head unit 700 to have a specific distance from the target substrate SUB.

[0090] For example, although one head unit 700 is shown in the accompanying drawings, the implementation is not limited thereto. For example, in the case of a process that provides multiple inks to a target substrate SUB, the same number of head units 700 as the types of inks can be provided.

[0091] The printhead unit 700 can move horizontally or vertically via the printhead moving unit. The printhead moving unit may include a first horizontal moving unit 330, a second horizontal moving unit 320, and a vertical moving unit 340.

[0092] The first horizontal moving unit 330 can be installed on the horizontal support portion 311, and the second horizontal moving unit 320 can be installed on the base frame 130.

[0093] The first horizontal moving unit 330 can move the head unit 700 in the second direction D2 on the horizontal support portion 311. The second horizontal moving unit 320 can move the vertical support portion 312 in the first direction D1 to move the head unit 700 mounted on the support unit 310 in the first direction D1.

[0094] By horizontally moving the first horizontal moving unit 330 and the second horizontal moving unit 320, ink can be splashed onto the entire area of ​​the target substrate SUB even when the printing process is performed using the head unit 700, whose area is smaller than that of the target substrate SUB.

[0095] The vertical moving unit 340 can adjust the distance between the head unit 700 and the stage 150 by raising or lowering the head unit 700 on the horizontal support portion 311 in the vertical direction. For example, when the target substrate SUB is placed on the stage 150, the position of the head unit 700 can be adjusted within a range that ensures processing space by using the vertical moving unit 340 to set the head unit 700 at a specific distance from the target substrate SUB.

[0096] Figure 9 This is a perspective view of the head unit according to the implementation method. Figure 10 This is a bottom view of the head unit according to the embodiment. Figure 11 It is along Figure 10 The sectional view taken along line I-I'. (Refer to...) Figure 9 , Figure 10 and Figure 11 The configuration of the head unit 700 is described in more detail.

[0097] The head unit 700 may include a head portion 710 and a body portion 720.

[0098] The body portion 720 may include a body chamber formed therein. Ink may be supplied to the body chamber of the body portion 720, and the supplied ink may flow into the head chamber HC through the first internal channel SM of the head portion 710, which will be described later. As will be described later, ink that has not yet been ejected through the nozzle NZ may be returned to the body chamber through the second internal channel RM.

[0099] The head portion 710 may form the bottom surface of the head unit 700. For example, the head portion 710 may face the platform 150 disposed below the head unit 700. The head portion 710 may have a shape that extends in one direction. The extending direction of the head portion 710 may be the same as the extending direction of the horizontal support portion 311 of the support unit 310. For example, the extending direction of the head portion 710 may be a second direction D2, where the second direction D2 is the direction of the long side of the platform 150.

[0100] The head portion 710 may include a nozzle NZ, internal channels SM and RM, and a head chamber HC. The head portion 710 may also include a plurality of stacked plates NP and PP. The plurality of plates NP and PP may include one or more nozzle plates NP and one or more channel plates PP. One or more nozzle plates NP may be disposed below one or more channel plates PP. Portions of the stacked plates NP and PP may be removed to define specific spaces, such as the nozzle NZ, internal channels SM and RM, and head chamber HC. The nozzle NZ may be formed by one or more nozzle plates NP, and the internal channels SM and RM and head chamber HC may be formed by one or more channel plates PP.

[0101] The internal channels SM and RM may include a first internal channel SM and a second internal channel RM, the first internal channel SM providing a path for ink to move from the body chamber to the head chamber HC, and the second internal channel RM providing a path for a portion of the ink (ink not ejected through the nozzle NZ) to return to the body chamber.

[0102] Filters FT1 and FT2, used to remove impurities included in the ink, can be installed within internal channels SM and RM. The first filter FT1 can be located within the first internal channel SM, and the second filter FT2 can be located within the second internal channel RM. The first filter FT1 and the second filter FT2 allow ink to pass through while filtering out impurities such as air bubbles.

[0103] The first filter FT1 can cover the entire width of the first internal channel SM, and the second filter FT2 can cover the entire width of the second internal channel RM. Therefore, the ink flowing through the first internal channel SM can pass entirely through the first filter FT1, and the ink flowing through the second internal channel RM can pass entirely through the second filter FT2.

[0104] The head chamber HC can provide space for storing ink in the head portion 710. As will be described later, the volume of the head chamber HC can be changed by deforming the membrane MB disposed on the head chamber HC.

[0105] Multiple nozzles NZ can be formed in the head portion 710. In an embodiment, the number of nozzles NZ included in a head portion 710 can be from 128 to 1800, but the embodiment is not limited thereto.

[0106] Multiple nozzles (NZs) can provide a path for ink to be ejected. Multiple nozzles (NZs) can penetrate the nozzle plate (NP) to spatially connect to the internal channels (SM and RM) and the head chamber (HC). For example, multiple nozzles (NZs) can be fluidly connected to, for example, communicated with, the internal channels (SM and RM) and the head chamber (HC). The specific shape of the nozzles (NZs) will be described later.

[0107] Nozzle NZ can be formed within nozzle plate NP. As described above, head unit 700 can include multiple nozzle plates NP. Multiple nozzle plates NP can form a stacked structure. In an embodiment, head unit 700 can include three nozzle plates NP. Hereinafter, a head unit 700 including three nozzle plates NP (e.g., a first nozzle plate NP1 constituting the bottom surface of the second internal channel RM, a second nozzle plate NP2 disposed below the first nozzle plate NP1, and a third nozzle plate NP3 disposed below the second nozzle plate NP2) will be described as an example, but the embodiment is not limited to the number of nozzle plates NP included in a head unit 700.

[0108] A waterproof layer AW can be applied to the bottom surface of each nozzle plate NP. The waterproof layer AW can cover the entire bottom surface of each nozzle plate NP. Here, the term "waterproof" can mean preventing moisture from liquids such as ink and water. Specifically, a first waterproof layer AW1 can be applied to the bottom surface of the first nozzle plate NP1, a second waterproof layer AW2 can be applied to the bottom surface of the second nozzle plate NP2, and a third waterproof layer AW3 can be applied to the bottom surface of the third nozzle plate NP3.

[0109] The surface properties of the nozzle plate (NP) can affect the droplet size of the ejected ink, as well as the ink ejection performance and stability of the nozzle (NZ).

[0110] When the bottom surface of the nozzle plate NP is hydrophilic, it can be wetted by the ink as it is repeatedly sprayed. When the surface of the nozzle plate NP is wetted, the ink forms clumps on its surface, causing it to flow downwards instead of forming complete droplets. As a result, the ink spray direction may be distorted and the ink spray speed may decrease, leading to deterioration of print quality and instability in the meniscus formed after ink spraying.

[0111] The waterproof layer (AW) prevents the bottom surface of the nozzle plate (NP) from being wetted by ink, thereby improving the spraying performance of the nozzle (NZ) described above. The waterproof layer (AW) can be formed using silicon or fluorine compounds. For example, polytetrafluoroethylene (PTFE), a Teflon-based material, can be used. Furthermore, the waterproof layer (AW) can be formed using various coating or deposition methods. For example, the waterproof layer (AW) can be formed through spin coating, physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD), etc.

[0112] An adhesive layer AL can be inserted between nozzle plates NP. The nozzle plates NP can be bonded to each other via the adhesive layer AL. Specifically, the top surface of the adhesive layer AL can contact the waterproof layer AW disposed on the bottom surface of the upper nozzle plate NP, and the bottom surface of the adhesive layer AL can contact the top surface of the lower nozzle plate NP. The adhesive layer AL can cover the entire top surface of the nozzle plate NP that contacts the corresponding adhesive layer AL. In an embodiment, a first adhesive layer AL1 can be inserted between a first waterproof layer AW1 and a second nozzle plate NP2, and a second adhesive layer AL2 can be inserted between a second waterproof layer AW2 and a third nozzle plate NP3.

[0113] The adhesive strength between the adhesive layer AL and the top surface of the nozzle plate NP that contacts the corresponding adhesive layer AL can be greater than the adhesive strength between the adhesive layer AL and the waterproof layer AW that contacts the corresponding adhesive layer AL, but the implementation is not limited to this. When the lower nozzle plate NP is removed, the waterproof layer AW provided on the bottom surface of the upper nozzle plate NP may not be removed. The adhesive layer AL can be a thermosetting adhesive sheet containing a thermosetting resin, but the implementation is not limited to this. For example, the adhesive layer AL can include adhesives containing various other materials.

[0114] The nozzle plate NP may include a plurality of through holes penetrating each nozzle plate NP in the thickness direction (e.g., in the vertical direction). Each of the through holes may have an internal structure that narrows downwards. For example, each of the through holes may include an upper inner surface having a first width and a lower inner surface having a second width less than the first width. However, the implementation is not limited to this. For example, each of the through holes may have a structure with a substantially constant width or a width that increases to one side in the third direction D3. For example, the upper portion of the through hole may have a wider width than its lower portion.

[0115] The through holes of the nozzle plate NP can be formed as a grid structure. The through holes of the nozzle plate NP can be arranged in one or more columns, and each column can include multiple through holes. In one embodiment, the nozzle plate NP can include through holes formed as a grid structure of 4 columns in the first direction D1 and 320 rows in the second direction D2, but the embodiment is not limited to this.

[0116] Since the nozzle plates NP are formed as a stacked structure, the through holes formed in the respective nozzle plates NP can overlap each other. Multiple through holes overlapping each other in the stacked nozzle plates NP can constitute a nozzle NZ. For example, a nozzle NZ can be a set of through holes overlapping each other in the nozzle plates NP. The nozzle NZ can have an internal structure that repeats the aforementioned through holes in the same number as the number of nozzle plates NP. In an embodiment, multiple nozzle NZs can be formed as a grid structure of 4 columns in the first direction D1 and 320 rows in the second direction D2, but the embodiment is not limited to this.

[0117] Ink supplied from the first internal channel SM can be ejected through multiple nozzles NZ. The ink ejected through the multiple nozzles NZ can be supplied to the top surface of the target substrate SUB. In an embodiment, the single ejection volume of each nozzle NZ can be from 1 to 50 picoliters, but the embodiment is not limited to this. The amount of ink ejected through the nozzles NZ can be adjusted by a piezoelectric actuator PZD. A detailed description of the piezoelectric actuator PZD will be given later.

[0118] A nozzle plate NP may include outwardly projecting protrusions PT1 or PT2. The protrusions PT1 or PT2 in a nozzle plate NP may be portions that project outward relative to the nozzle plate NP disposed thereon. The protrusions PT1 or PT2 may facilitate the disassembly of the nozzle plate NP physically connected to the corresponding protrusions PT1 or PT2. For example, the protrusions PT1 or PT2 may be grasped using tools such as pliers or tweezers to disassemble the nozzle plate NP connected to the corresponding protrusions PT1 or PT2.

[0119] The protrusion PT1 or PT2 may be provided on one of the several sides of the nozzle plate NP, but the embodiment is not limited to this, and it may be provided on multiple sides. In the nozzle plate NP including the protrusion PT1 or PT2, the protrusion PT1 or PT2 may protrude outward on the entire side surface of the nozzle plate NP, but the embodiment is not limited to this.

[0120] In one embodiment, the second nozzle plate NP2 may include a first protrusion PT1, and the third nozzle plate NP3 may include a second protrusion PT2. The first nozzle plate NP1, which contacts the channel plate PP, may not include either protrusion PT1 or PT2, but the embodiment is not limited thereto. For example, the first protrusion PT1 may be an upper protrusion, and the second protrusion PT2 may be a lower protrusion below the upper protrusion.

[0121] The nozzle plate NP can be formed from a substrate made of a material with good fine processing properties. For example, the nozzle plate NP can be formed from a stainless steel substrate or a silicon substrate, but the implementation is not limited to this. The thickness of the nozzle plate NP can be from about 20 μm to 100 μm. For example, the nozzle plate NP can have a thickness of about 50 μm, but the implementation is not limited to this.

[0122] The channel plate PP can be mounted on the nozzle plate NP. The channel plate PP can form the head chamber HC and the internal channels SM and RM described above.

[0123] The head unit 700 according to an embodiment may include a plurality of channel plates PP. The plurality of channel plates PP may have a stacked structure. In an embodiment, the head unit 700 may include five channel plates PP. Hereinafter, a head unit 700 including five channel plates PP (e.g., a fifth channel plate PP5 disposed on the nozzle plate NP, a fourth channel plate PP4 disposed on the fifth channel plate PP5, a third channel plate PP3 disposed on the fourth channel plate PP4, a second channel plate PP2 disposed on the third channel plate PP3, and a first channel plate PP1 disposed on the second channel plate PP2) will be described as an example, but the embodiment is not limited to the number of channel plates PP included in a single head unit 700. Furthermore, the internal channels SM and RM formed within the channel plates PP, the head chamber HC, etc., may be arranged in different configurations.

[0124] Internal channels SM and RM, as well as the head chamber HC, can be formed within the channel plate PP. Ink supplied from the body chamber of the body portion 720 flows into the interior of the channel plate PP through the ink inlet IL. The head chamber HC can be formed within the channel plate PP, and ink introduced through the first internal channel SM can be stored therein. The first internal channel SM, connecting the ink inlet IL to the head chamber HC, can be formed within the channel plate PP. Ink filled in the head chamber HC can be ejected in droplet form through the nozzle NZ. One head chamber HC can be provided corresponding to each nozzle NZ. Ink that has not yet been ejected through the nozzle NZ can be returned to the body chamber of the body portion 720 through the second internal channel RM and the ink outlet OL.

[0125] The ink inlet IL can be formed to penetrate the uppermost substrate, such as the first channel plate PP1, and the head chamber HC can be formed between the film MB and the fourth channel plate PP4.

[0126] The first internal channel SM can be formed between the second channel plate PP2 and the fourth channel plate PP4, and the second internal channel RM can be formed between the fourth channel plate PP4 and the nozzle plate NP.

[0127] The channel plate PP can be formed from a substrate made of a material with good fine processing properties. For example, the channel plate PP can be formed from a stainless steel substrate or a silicon substrate, but the implementation is not limited to these. The thickness of the channel plate PP can be from about 20 μm to 100 μm. For example, the channel plate PP can have a thickness of about 50 μm, but the implementation is not limited to these.

[0128] The channel plate PP can be made of the same material and have the same thickness as the nozzle plate NP, but the implementation is not limited to this.

[0129] For example, an adhesive layer may be inserted between the channel plates PP forming the stacked structure. The adhesive layer inserted between the channel plates PP may be made of the same material as the adhesive layer AL inserted between the nozzle plates NP, but the implementation is not limited to this.

[0130] The head unit 700 according to the embodiment may further include a piezoelectric actuator PZD. The piezoelectric actuator PZD can control the ink ejection amount of each nozzle NZ, and one PZD can be provided for each nozzle NZ. The piezoelectric actuator PZD can be disposed above the head chamber HC. The membrane MB can be disposed between the piezoelectric actuator PZD and the head chamber HC. The membrane MB can form the top of the head chamber HC.

[0131] When a drive signal is applied to the piezoelectric actuator PZD, the membrane MB beneath the actuator PZD deforms along with it, reducing the volume of the head chamber HC and increasing the pressure within HC. Due to the increased pressure in HC, the ink within HC can be ejected to the outside through the nozzle NZ.

[0132] The drive signal transmitted to the piezoelectric driver PZD can be controlled by the piezoelectric controller PZC located outside the head unit 700.

[0133] Figure 12 This is a flowchart illustrating the process of inspecting an inkjet printing device according to an embodiment. Figure 13 and Figure 14 It is a perspective view of a substrate on which impact points have been formed using an inkjet printing apparatus according to an embodiment. Figure 15 , Figure 16 and Figure 17 This is a cross-sectional view showing the process of removing the nozzle plate from the contaminated head unit.

[0134] Reference Figure 12 , Figure 13 and Figure 14 The process of inspecting the inkjet printing equipment according to the embodiment may include repeating inkjet printing n times on the target substrate SUB1 (step S11). n is a positive integer. Ink can be ejected from the inkjet printing equipment 1000 to form impact dots HP on the target substrate SUB1. The impact dots HP on the target substrate SUB1 can be arranged in a row. The impact dots HP arranged in a row can form an imaginary impact line HL.

[0135] When multiple inkjet printing operations are performed on the target substrate SUB1 using inkjet printing equipment 1000, contaminants may gradually form in the nozzles NZ of the inkjet printing equipment 1000, and the accumulated contaminants may cause manufacturing errors. For example, such as Figure 14As shown, manufacturing errors may include alignment errors d on the test substrate SUB2. For example, when inkjet printing is performed on the test substrate SUB2, the impact point HP may be formed on the test substrate SUB2 away from the impact line HL. Considering the performance of the display device 1, it is preferable that the alignment error d from the impact line HL to the impact point HP is about 10 μm or less.

[0136] Therefore, as a process for testing the inkjet printing equipment 1000, the process of checking the alignment error d on the test substrate SUB2 can be performed every time the inkjet printing is repeated n times on the target substrate SUB1 (step S21). Although the repeated inkjet printing on the target substrate SUB1 is described as being performed n times, it can be performed for about 10 to 20 hours based on the running time.

[0137] The impact points HP printed on the test substrate SUB2 may be spaced apart from the impact lines HL, resulting in an alignment error d. In this case, when there are no impact points HP with an alignment error d of 10 μm or greater, the inkjet printing process can be performed again on the target substrate SUB1 (step S11). This process can have a shorter run time than the previously performed inkjet printing process. Afterwards, the process of testing the inkjet printing equipment 1000 can be performed again (step S21).

[0138] Among the multiple impact points HP formed on the test substrate SUB2, when at least one impact point HP has an alignment error d of 10 μm or greater with the impact line HL, the outermost nozzle plate NP (e.g., the third nozzle plate NP3) can be separated or removed (step S31). By separating the outermost nozzle plate NP from the head unit 700, contaminants formed around the nozzle NZ can be removed or cleaned.

[0139] This process can be repeated until the number of nozzle plates NP becomes zero (step S41), for example, until the first nozzle plate NP1 is separated or removed.

[0140] The process of removing the nozzle plate NP from the head unit 700, on which contaminants have accumulated, will be described below.

[0141] Reference Figure 15 , Figure 16 and Figure 17 When the ink jetting process is repeated using the inkjet printing apparatus 1000 according to the embodiment, contaminant CTs, comprising organic or inorganic substances contained in the ink, may form near the jetting opening of the nozzle NZ. For example, contaminant CTs may include the substances mentioned above. Figure 2 The wavelength conversion materials WCP1 and WCP2, the scatterer SCP, and the base resins BRS1, BSR2, and BSR3 are described.

[0142] In this way, when contaminant CT forms near the nozzle NZ's ejection opening, the nozzle NZ may become blocked or the ink ejection path may be altered, resulting in... Figure 14 The poor ink impact shown is illustrated.

[0143] Figure 15 The illustration shows a case where the contaminant CT is formed only on the third nozzle plate NP3, which is the outermost nozzle plate NP. However, the implementation is not limited to this, and the contaminant CT can be formed on multiple nozzle plates NP.

[0144] To resolve the contamination issue, the nozzle plate NP with the contaminant CT formed on it can be removed. The third nozzle plate NP3 with the contaminant CT formed on it can be disassembled by grasping the second protrusion PT2. The specific disassembly method is the same as those described above for protrusions PT1 or PT2.

[0145] Once the third nozzle plate NP3, on which contaminants CT have formed, is removed, the ink ejected through nozzle NZ can then travel along... Figure 13 The straight impact line HL shown forms the impact point HP.

[0146] The inkjet printing apparatus 1000 according to the embodiment may include a plurality of nozzle plates NP having a stacked structure, and each of the nozzle plates NP can be easily disassembled. Therefore, when a particular nozzle NZ has a problem, only the nozzle plate NP containing the particular nozzle NZ can be removed from the plurality of nozzle plates NP, thereby reducing the cost of replacing the head unit 700. In addition, the replacement time of the head unit 700 can be shortened, thereby improving the production efficiency of the inkjet printing apparatus 1000.

[0147] Other embodiments of the inkjet printing apparatus 1000 will be described below. In these embodiments, for ease of description, descriptions of components identical to those in the above embodiments will be omitted or simplified, and the differences will be mainly described.

[0148] Figure 18 This is a perspective view showing a nozzle plate according to another embodiment.

[0149] Reference Figure 18 The inkjet printing apparatus according to this embodiment differs from the inkjet printing apparatus 1000 according to the above embodiment in that the inkjet printing apparatus includes a nozzle plate NP_1, which is different from the nozzle plate NP included in the inkjet printing apparatus 1000. Hereinafter, the differences between the nozzle plate NP_1 according to this embodiment and the nozzle plate NP according to the above embodiment will be mainly described.

[0150] The inkjet printing apparatus according to this embodiment may include a protrusion PT1_1 or PT2_1 projecting outward from a portion of a side surface of a nozzle plate NP_1. Figure 18 In the illustration, protrusions PT1_1 or PT2_1 are shown as being provided on the short side surface of the nozzle plate NP_1, but the embodiment is not limited to this. For example, protrusions PT1_1 or PT2_1 may be provided on the long side surface of the nozzle plate NP_1. Furthermore, multiple protrusions PT1_1 or PT2_1 may be provided on a single nozzle plate NP_1.

[0151] The width of the protrusion PT1_1 or PT2_1 may be less than the width of the side surface on which the protrusion PT1_1 or PT2_1 is provided. Furthermore, the thickness of the protrusion PT1_1 or PT2_1 may be the same as the thickness of the nozzle plate NP_1 physically connected to the protrusion PT1_1 or PT2_1, but the implementation is not limited to this. For example, the thickness of the protrusion PT1_1 or PT2_1 may be less than the thickness of the nozzle plate NP_1. Each of the protrusions PT1_1 and PT2_1 may not overlap in the thickness direction (e.g., in the vertical direction), thereby facilitating gripping.

[0152] In one embodiment, the second nozzle plate NP2_1 may include a first protrusion PT1_1, and the third nozzle plate NP3_1 may include a second protrusion PT2_1. The first protrusion PT1_1 may cover a portion of one side surface of the second nozzle plate NP2_1, and the second protrusion PT2_1 may cover a portion of one side surface of the third nozzle plate NP3_1. The first nozzle plate NP1_1 may not have protrusions PT1_1 or PT2_1.

[0153] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_1 having a stacked structure, and each of the nozzle plates NP_1 can be easily separated or disassembled. Therefore, when a particular nozzle NZ_1 has a problem, only the nozzle plate NP_1 containing the specific nozzle NZ_1 can be removed or disassembled, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0154] Figure 19 This is a perspective view showing a nozzle plate according to yet another embodiment.

[0155] The inkjet printing apparatus according to this embodiment may include a nozzle plate NP_2 divided into multiple regions. Specifically, the nozzle plate NP_2 according to this embodiment may be divided into multiple sub-nozzle plates arranged along the long side direction of the nozzle plate NP_2. The number of sub-nozzle plates included in one nozzle plate NP_2 is two or more, and may be less than or equal to the number of nozzles NZ_2 arranged along the long side direction of one nozzle plate NP_2. Protrusions PT_2 (e.g., PT11_2, PT12_2, PT13_2, ..., PT1n_2 and PT21_2, PT22_2, PT23_2, ..., PT2n_2) may be provided on the short side surfaces of the sub-nozzle plates of the second nozzle plate NP2_2 and the sub-nozzle plates of the third nozzle plate NP3_2. Protrusions PT_2 may not be provided on the first nozzle plate NP1_2.

[0156] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_2 having a stacked structure, and each of the nozzle plates NP_2 can be easily separated or disassembled. Therefore, when a particular nozzle NZ_2 has a problem, only the sub-nozzle plate of the nozzle plate NP_2 containing the specific nozzle NZ_2 can be removed or disassembled, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0157] Figure 20 This is a perspective view showing a nozzle plate according to yet another embodiment.

[0158] Reference Figure 20 The inkjet printing apparatus according to this embodiment may include a nozzle plate NP_3 divided into multiple regions. Specifically, the nozzle plate NP_3 according to this embodiment may be divided into multiple sub-nozzle plates arranged along the short side direction of the nozzle plate NP_3. The number of sub-nozzle plates included in one nozzle plate NP_3 is two or more, and may be less than or equal to the number of nozzles NZ_3 arranged along the short side direction of the nozzle plate NP_3. The nozzle plate NP_3 according to this embodiment may include four sub-nozzle plates, but the embodiment is not limited to the number of sub-nozzle plates. Protrusions PT_3 (e.g., PT11_3, PT12_3, PT13_3, PT14_3, PT21_3, PT22_3, PT23_3, and PT24_3) may be provided on the short side surfaces of the sub-nozzle plates of the second nozzle plate NP2_3 and the sub-nozzle plates of the third nozzle plate NP3_3. Protrusions PT_3 may not be provided on the first nozzle plate NP1_3.

[0159] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_3 having a stacked structure, and each of the nozzle plates NP_3 can be easily separated or disassembled. Therefore, when a particular nozzle NZ_3 has a problem, only the sub-nozzle plate of the nozzle plate NP_3 containing the specific nozzle NZ_3 can be removed, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0160] Figure 21 This is a cross-sectional view of the nozzle of the nozzle plate according to yet another embodiment.

[0161] In the inkjet printing apparatus according to this embodiment, the through holes formed in the nozzle plate NP_4 may be misaligned. Specifically, the first imaginary line L1 passing through the center of the through hole in the first nozzle plate NP1_4, the second imaginary line L2 passing through the center of the through hole in the second nozzle plate NP2_4, and the third imaginary line L3 passing through the center of the through hole in the third nozzle plate NP3_4 may be misaligned. The ink ejected from the inkjet printing apparatus according to this embodiment may be ejected primarily along the first imaginary line L1, the second imaginary line L2, and the third imaginary line L3.

[0162] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_4 having a stacked structure, and each of the nozzle plates NP_4 can be easily separated or disassembled. Therefore, when a specific nozzle NZ_4 has a problem, only the nozzle plate NP_4 containing the specific nozzle NZ_4 can be removed or disassembled, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0163] Figure 22 This is a cross-sectional view of the nozzle of the nozzle plate according to yet another embodiment.

[0164] In the inkjet printing apparatus according to this embodiment, the through holes formed in the nozzle plate NP_5 can have different widths (e.g., diameters) from one another. Specifically, the first width W1, the second width W2, and the third width W3 can be different from one another, wherein the first width W1 is the width of the through hole included in the first nozzle plate NP1_5, the second width W2 is the width of the through hole included in the second nozzle plate NP2_5, and the third width W3 is the width of the through hole included in the third nozzle plate NP3_5.

[0165] In this embodiment, the width of the nozzle NZ_5 in the nozzle plate NP_5 with the stacked structure can be increased downwards. For example, the second width W2 can be greater than the first width W1, and the third width W3 can be greater than the second width W2, but the embodiment is not limited thereto. When the width is increased downwards, the effect of the ejected ink on the nozzle NZ_5 can be minimized.

[0166] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_5 having a stacked structure, and each of the nozzle plates NP_5 can be easily separated or disassembled. Therefore, when a specific nozzle NZ_5 has a problem, only the nozzle plate NP_5 containing the specific nozzle NZ_5 can be removed or disassembled from the multiple nozzle plates NP_5, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0167] Figure 23 This is a cross-sectional view of the nozzle of the nozzle plate according to yet another embodiment.

[0168] In the inkjet printing apparatus according to this embodiment, the width (e.g., diameter) of the through holes formed in the nozzle plates NP1_6, NP2_6, and NP3_6 is substantially constant, such that the width W_6 of the nozzle NZ_6 formed in the nozzle plate NP_6 is substantially constant throughout the entire nozzle plate NP_6. The widths of the through holes included in the first nozzle plate NP1_6, the second nozzle plate NP2_6, and the third nozzle plate NP3_6 can be the same as each other.

[0169] The inkjet printing apparatus according to this embodiment may include multiple nozzle plates NP_6 having a stacked structure, and each of the nozzle plates NP_6 can be easily disassembled. Therefore, when a particular nozzle NZ_6 has a problem, only the nozzle plate NP_6 containing the particular nozzle NZ_6 can be removed, thereby reducing the cost of replacing the head unit. Furthermore, the head unit replacement time can be shortened, thereby improving the production efficiency of the inkjet printing apparatus.

[0170] In closing, those skilled in the art will understand that many variations and modifications can be made to the preferred embodiments without departing from the principles of the invention. Therefore, the preferred embodiments disclosed herein are used in a general and descriptive sense only and are not intended to be limiting.

Claims

1. An inkjet printing apparatus comprising: a channel plate in which a head chamber is provided; a plurality of nozzle plates disposed below the channel plate, the plurality of nozzle plates including nozzles fluidly connected with the head chamber; and at least one protrusion outwardly extending from at least one of the plurality of nozzle plates, wherein: the plurality of nozzle plates are stacked with each other, and the nozzles of the plurality of nozzle plates are formed by a plurality of through-holes passing through the plurality of nozzle plates and overlapping each other. The at least one protrusion outwardly extends from a side surface of at least one of the plurality of nozzle plates.

2. The inkjet printing apparatus according to claim 1, wherein A waterproof layer is provided on a bottom surface of each of the plurality of nozzle plates.

3. The inkjet printing apparatus according to claim 1, wherein An adhesive layer is provided between the waterproof layer and a nozzle plate of the plurality of nozzle plates under the waterproof layer.

4. The inkjet printing apparatus according to claim 3, wherein An adhesive strength between the adhesive layer and an upper surface of each of the plurality of nozzle plates is greater than an adhesive strength between the adhesive layer and the waterproof layer.

5. The inkjet printing apparatus according to claim 4, wherein Each of the plurality of through-holes of the plurality of nozzle plates includes an upper inner side surface having a first width and a lower inner side surface having a second width smaller than the first width.

6. The inkjet printing apparatus of claim 1, wherein, 7.The inkjet printing apparatus of claim 6, wherein: the plurality of nozzle plates include a first nozzle plate and a second nozzle plate disposed on the first nozzle plate, and the first width of the through-hole of the first nozzle plate is greater than the first width of the through-hole of the second nozzle plate. The plurality of nozzle plates include:

8. The inkjet printing apparatus of claim 1, wherein, a first nozzle plate; and a second nozzle plate disposed on the first nozzle plate. A first waterproof layer is provided on a bottom surface of the first nozzle plate, and a second waterproof layer is provided on a bottom surface of the second nozzle plate.

9. The inkjet printing apparatus of claim 8, wherein, 10.The inkjet printing apparatus of claim 1, wherein each of the plurality of nozzle plates includes a plurality of sub-nozzle plates arranged in one direction. ​

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