Inkjet printing apparatus

Abstract

The invention relates to an inkjet printing apparatus. The inkjet printing apparatus includes: an inkjet head; an ink supply device connected to the inkjet head; a cleaning cylinder below the inkjet head and connected to the ink supply device; the first channel is connected with the cleaning cylinder and the ink supply equipment; and a densitometer in the first channel.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0142475 filed in the Korean Intellectual Property Office on October 23, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] Aspects of some embodiments of the present disclosure relate to inkjet printing apparatus. Background Art

[0004] With the development of multimedia technology, the importance of display devices is increasing. Such display devices include, for example, liquid crystal displays (LCDs), organic light emitting displays (OLEDs), etc. Such display devices can be used with or incorporated into various mobile electronic devices, such as portable electronic devices such as smart phones, smart watches, and tablet PCs.

[0005] The organic light emitting display includes a display panel having an organic light emitting element in which a cathode electrode and an anode electrode are arranged with respect to an organic light emitting layer, and when a voltage is applied to the two electrodes, visible light is generated from the organic light emitting layer connected to the two electrodes.

[0006] Meanwhile, an organic light-emitting layer of an organic light-emitting display may be formed using an inkjet printing device, in which ink or a solution (e.g., a predetermined ink or solution) may be supplied to an inkjet head, and the inkjet head may perform a process of ejecting the ink or the solution on a substrate to be processed (e.g., a target substrate) while the substrate to be processed reciprocates.

[0007] The above information disclosed in this Background section is only for enhancement of understanding of the background technology and therefore the information discussed in this Background section does not necessarily constitute prior art. Summary of the invention

[0008] Aspects of some embodiments of the present disclosure include inkjet printing apparatus having relatively increased ink reuse rates.

[0009] Aspects of some embodiments of the present disclosure may also include an inkjet printing apparatus having relatively improved reliability of ink quality.

[0010] However, aspects of the present disclosure are not limited to those set forth herein. The above and other aspects of the present disclosure will become more apparent to those of ordinary skill in the art to which the present disclosure pertains by referring to the detailed description of the present disclosure given below.

[0011] According to some embodiments of the present disclosure, an inkjet printing device includes: an inkjet head; an ink supply device connected to the inkjet head; a cleaning tank below the inkjet head and connected to the ink supply device; a first channel connecting the cleaning tank and the ink supply device; and a densitometer in the first channel.

[0012] According to some embodiments, a densitometer includes: a measurement source generator; a measurement source detector configured to detect a measurement source generated from the measurement source generator; and a controller configured to receive information about the measurement source from the measurement source detector and the measurement source generator, respectively.

[0013] According to some embodiments, the measurement source generator and the measurement source detector are located on opposite sides, and the first channel is interposed between the measurement source generator and the measurement source detector.

[0014] According to some embodiments, the measurement source generator and the measurement source detector are located on the same side relative to the first channel.

[0015] According to some embodiments, a measurement source generated from a measurement source generator interacts with ink located in the first channel.

[0016] According to some embodiments, the measurement source generator provides a first signal to the controller containing information about a measurement source generated from the measurement source generator, the measurement source detector provides a second signal to the controller containing information about the measurement source interacting with the ink, and the controller generates a third signal based on the first signal and the second signal.

[0017] According to some embodiments, the inkjet printing apparatus may further include a solvent supply connected to at least one of the cleaning tank, the first channel, and the ink supply, wherein the controller is configured to provide a third signal to the solvent supply.

[0018] According to some embodiments, the solvent supply device receiving the third signal is configured to supply the solvent of the ink to at least one of the cleaning tank, the first channel, and the ink supply device.

[0019] According to some embodiments, the inkjet printing apparatus may further include a filter between the densitometer and the cleaning tank.

[0020] According to some embodiments, the washing tub includes a door that controls the opening and closing of the washing tub.

[0021] According to some embodiments, the door includes a door driver configured to provide a driving force to the door.

[0022] According to some embodiments, the inkjet printing apparatus may further include: a suction channel connecting the inkjet head and a door of the cleaning tank; and a suction device connected to the suction channel.

[0023] According to some embodiments, the door includes a suction opening in communication with the suction channel, and the suction opening is configured to move along the suction channel.

[0024] According to some embodiments, the inner wall of the cleaning tub includes a superhydrophobic coating film.

[0025] According to some embodiments, the level of ink in the wash tank is maintained at a constant level.

[0026] According to some embodiments, the inkjet printing device may further include a removal tank connected to the cleaning cylinder, wherein the removal tank is not connected to the ink supply device.

[0027] According to some embodiments, the inkjet printing device may further include a second channel connecting the cleaning tank and the ink supply device and being different from the first channel, wherein the ink flow directions of the first channel and the second channel are different.

[0028] According to some embodiments, the inkjet printing apparatus may further include a scraper located between the inkjet head and the cleaning cylinder, wherein the scraper is configured to wipe a bottom surface of the inkjet head.

[0029] According to some embodiments of the present disclosure, an inkjet printing device includes: an ink supply device; an ink storage device configured to receive ink from the ink supply device; an inkjet head configured to receive ink from the ink storage device; a cleaning tank configured to collect ink ejected from the inkjet head; a first channel configured to move ink from the cleaning tank to the ink supply device; a densitometer configured to measure the concentration of ink located in the first channel; and a solvent supply device configured to supply a solvent for the ink to at least one of the ink supply device, the cleaning tank, and the first channel.

[0030] According to some embodiments, the inkjet printing device may further include a first pump in the first channel and configured to provide a driving force from the cleaning tank toward the ink supply device.

[0031] According to some embodiments, the inkjet printing device may further include a second channel that is different from the first channel and is configured to move ink from the ink supply device to the cleaning tank.

[0032] According to some embodiments, the inkjet printing apparatus may further include a third channel configured to move a solvent of the ink from the solvent supply device to at least one of the ink supply device, the cleaning tank, and the first channel.

[0033] According to some embodiments, the inkjet printing apparatus may further include a second pump in the third channel and configured to provide a driving force from the solvent supply device toward at least one of the ink supply device, the cleaning tank, and the first channel.

[0034] In the inkjet printing apparatus according to some embodiments of the present disclosure, the ink reuse rate may be relatively increased.

[0035] In the inkjet printing apparatus according to some embodiments of the present disclosure, the reliability of ink quality may be relatively improved.

[0036] However, the characteristics of the embodiments of the present disclosure are not limited to those described above, and various other characteristics are incorporated herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other aspects and features according to embodiments of the present disclosure will become more apparent by describing aspects of some embodiments of the present disclosure in more detail with reference to the accompanying drawings, in which:

[0038] Figure 1 is a plan view showing a display device according to some embodiments;

[0039] Figure 2 According to some embodiments, Figure 1 A cross-sectional view taken along the line X1-X1';

[0040] Figure 3 According to some embodiments Figure 2 An enlarged view of area A;

[0041] Figure 4 is a diagram showing an equivalent circuit of a circuit layer according to some embodiments;

[0042] Figure 5 is a cross-sectional view showing a state in which an inkjet printing apparatus according to some embodiments performs a printing process;

[0043] Figure 6 is a cross-sectional view showing a state in which an inkjet printing apparatus according to some embodiments performs a head care process;

[0044] Figure 7 is a cross-sectional view showing a state in which a head care process is completed in an inkjet printing apparatus according to some embodiments;

[0045] Figure 8 According to some embodiments Figure 6 An enlarged view of region B;

[0046] Fig. 9 is a schematic block diagram illustrating a densitometer according to some embodiments;

[0047] Fig.10 is a schematic block diagram illustrating a densitometer according to some embodiments;

[0048] Fig.11is a cross-sectional view of an inkjet printing apparatus according to some embodiments;

[0049] Fig.12 is a bottom view showing an inkjet head of an inkjet printing apparatus according to some embodiments;

[0050] Fig.13 and Fig.14 is a cross-sectional view of an inkjet printing apparatus according to some embodiments; and

[0051] Fig.15 and Fig.16 is a cross-sectional view of an inkjet printing apparatus according to some embodiments. DETAILED DESCRIPTION

[0052] Aspects of some embodiments of the present disclosure will now be described more fully below with reference to the accompanying drawings, in which aspects of some embodiments of the present disclosure are shown. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be more thorough and more complete, and will more fully convey the scope of the embodiments according to the present disclosure to those skilled in the art.

[0053] It will also be understood that when a layer is referred to as being 'on' another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Throughout the specification, the same reference numerals refer to the same components.

[0054] Hereinafter, aspects of some embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings.

[0055] Figure 1 is a plan view showing a display device according to some embodiments.

[0056] refer to Figure 1 , the display device DD may refer to any electronic device that provides a display screen. The display device DD may display a moving image (e.g., a video image) or a still image (e.g., a static image). Examples of the display device DD may include a television that provides a display screen, a laptop computer, a monitor, a billboard, an Internet of Things device, a mobile phone, a smart phone, a tablet personal computer (PC), an electronic watch, a smart watch, a watch phone, a head-mounted display, a mobile communication terminal, an electronic notebook, an electronic book, a portable multimedia player (PMP), a navigation device, a game console, a digital camera, a camcorder, etc.

[0057] According to some embodiments, the display device DD may have a rectangular shape (e.g., or a substantially rectangular shape) in a plan view. The display device DD may include two long sides extending in a first direction DR1 and two short sides extending in a second direction DR2 intersecting the first direction DR1. The corner where the long side and the short side of the display device DD intersect may have a right angle. However, embodiments according to the present disclosure are not limited thereto, and the corner may have a curved surface. According to some embodiments, the long side may extend in the second direction DR2, and the short side may extend in the first direction DR1. The planar shape of the display device DD is not limited to the shape shown, but may have a circular shape or other shapes.

[0058] In the illustrated figures, the first direction DR1 and the second direction DR2 intersect each other as horizontal directions. For example, the first direction DR1 and the second direction DR2 may be orthogonal to each other. In addition, the third direction DR3 intersects the first direction DR1 and the second direction DR2, and may be, for example, vertical directions orthogonal to each other. Unless otherwise defined, in this specification, the direction indicated by the arrows of the first direction DR1, the second direction DR2, and the third direction DR3 may be referred to as one side, and the direction opposite thereto may be referred to as the other side.

[0059] The display device DD may include a display panel that provides a display screen. Examples of the display panel may include an inorganic light emitting diode display panel, an organic light emitting display panel, a quantum dot light emitting display panel, a plasma display panel, and a field emission display panel. In the following description, a case where an organic light emitting diode display panel is used as a display panel will be described, but the embodiments of the present disclosure are not limited thereto, and other display panels may be applied within the same scope of the technical spirit.

[0060] The display device DD may include a display area DA and a non-display area NDA arranged around the display area DA (e.g., outside the periphery or coverage area of ​​the display area DA). The display area DA is an area where a picture (or image) is displayed, and the non-display area NDA is an area where a picture (or image) is not displayed. The display area DA may also be referred to as an active area, and the non-display area NDA may also be referred to as a non-active area. The display area DA substantially occupies the center of the display device DD, and the non-display area NDA may be arranged to surround the display area DA.

[0061] The display area DA may include a plurality of pixels PX. The plurality of pixels PX may be arranged in a matrix. In a plan view, the shape of each pixel PX may be a rectangle or a square. However, the embodiment of the present disclosure is not limited thereto, and it may be a rhombus shape in which each side is inclined relative to one direction.

[0062] As described above, the non-display area NDA may be arranged around the display area DA. The non-display area NDA may completely or partially surround the display area DA. The display area DA may have a rectangular shape, and the non-display area NDA may be arranged adjacent to four sides of the display area DA. The non-display area NDA may form a frame of the display device DD. A wiring or circuit driver included in the display device DD may be located in the non-display area NDA, or an external device may be mounted thereon.

[0063] Figure 2 It is along Figure 1 A cross-sectional view taken along line X1-X1'.

[0064] refer to Figure 2 The display device DD may include a display substrate 1 , a color conversion substrate 2 facing the display substrate 1 , a sealing portion 4 bonding the display substrate 1 to the color conversion substrate 2 , and a filler 3 filled between the display substrate 1 and the color conversion substrate 2 .

[0065] The display substrate 1 may include elements and circuits for displaying images, for example, pixel circuits such as switching elements, self-luminous elements, and pixel defining layers defining emission areas and non-emission areas. According to some embodiments, the self-luminous element may include at least one of an organic light emitting diode, a quantum dot light emitting diode, an inorganic micro light emitting diode (e.g., micro-LED), and an inorganic nano light emitting diode (e.g., nano-LED).

[0066] Color conversion substrate 2 may be located on display substrate 1 to face display substrate 1. According to some embodiments, color conversion substrate 2 may include a color conversion pattern for converting the color of incident light. According to some embodiments, the color conversion pattern may include at least one of a color filter and a wavelength conversion pattern.

[0067] The sealing portion 4 may be located between the display substrate 1 and the color conversion substrate 2 in the non-display area NDA. The sealing portion 4 may be arranged along the edges of the display substrate 1 and the color conversion substrate 2 in the non-display area NDA to surround the display area DA in a plan view (e.g., outside the periphery or footprint of the display area DA). The display substrate 1 and the color conversion substrate 2 may be bonded to each other through the sealing portion 4.

[0068] Filler 3 may be located in a space between display substrate 1 and color conversion substrate 2 surrounded by sealing portion 4. Filler 3 may fill the space between display substrate 1 and color conversion substrate 2. Filler 3 may be made of a material that may transmit light. In some embodiments, filler 3 may be omitted.

[0069] Figure 3 yes Figure 2Magnified view of area A.

[0070] refer to Figure 3 The display device DD may include a display substrate 1 , a color conversion substrate 2 facing the display substrate 1 , and a filler 3 filled between the display substrate 1 and the color conversion substrate 2 .

[0071] The display substrate 1 may include a first base substrate SUB1, a circuit layer CCL, a pixel defining layer PDL, a light emitting element EMD, and a thin film encapsulation layer TFEL.

[0072] The first base substrate SUB1 may include a transparent material. For example, the first base substrate SUB1 may include a transparent insulating material such as glass, quartz, etc. The first base substrate SUB1 may be a rigid substrate. However, the first base substrate SUB1 is not limited thereto. The first base substrate SUB1 may include a plastic such as polyimide, etc., and may have a flexible property so that it can be twisted, bent, folded, or curled.

[0073] The circuit layer CCL may be located on the first base substrate SUB1. The circuit layer CCL may include transistors and various circuit wirings for driving the light emitting element EMD. The circuit layer CCL may be located between the first base substrate SUB1 and the light emitting element EMD. Figure 4 Describe the circuit layer CCL.

[0074] The pixel defining layer PDL may be located on the pixel electrode PXE along the boundary of the pixel PX. The pixel defining layer PDL may include an opening exposing at least a portion of the pixel electrode PXE. The emission region and the non-emission region may be distinguished by the pixel defining layer PDL and its opening.

[0075] The pixel defining layer PDL may include an organic insulating material such as acrylic resin, epoxy resin, phenolic resin, polyamide resin, polyimide resin, unsaturated polyester resin, polyphenylene ether resin, polyphenylene sulfide resin, or benzocyclobutene (BCB). The pixel defining layer PDL may include an inorganic material.

[0076] The light emitting element EMD may be located on the circuit layer CCL. Figure 3 One pixel PX is shown in FIG. 1 to illustrate one light emitting element EMD, but the display substrate 1 may include a plurality of light emitting elements EMD arranged for each pixel PX.

[0077] The light emitting element EMD may include a pixel electrode PXE, a light emitting layer EML, and a common electrode CME.

[0078] The pixel electrode PXE may be located on the circuit layer CCL of the display substrate 1. The pixel electrode PXE may be a first electrode (e.g., an anode electrode) of the light emitting element EMD. The pixel electrode PXE may have a structure formed by stacking a material layer having a high work function (such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), and indium oxide (In 2 O 3 )) and a reflective material layer (such as silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), lead (Pb), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca) or a mixture thereof) to form a stacked structure. The material layer with a high work function may be located above the reflective material layer and closer to the light-emitting layer EML. The pixel electrode PXE may have a multilayer structure such as ITO / Mg, ITO / MgF 2 , ITO / Ag and ITO / Ag / ITO, but not limited to.

[0079] The light-emitting layer EML may be located on the pixel electrode PXE exposed by the pixel defining layer PDL. According to some embodiments in which the display device DD is an organic light-emitting display, the light-emitting layer EML may include an organic layer having an organic material. The organic layer may have an organic light-emitting layer, and in some cases, may further have at least one of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer as an auxiliary layer for emitting light. According to some embodiments, when the display device DD is a micro-LED display device, a nano-LED display device, etc., the light-emitting layer EML may include an inorganic material such as an inorganic semiconductor. According to some embodiments, the light-emitting layer EML may be printed using an inkjet printing device 10 (see FIG. 1 ) described in more detail later. Figure 5 ) to form.

[0080] According to some embodiments, the wavelength of light emitted from each light emitting layer EML may be the same regardless of the pixel PX. For example, the light emitting layer EML of each pixel PX may emit blue light or ultraviolet light, and the color conversion substrate 2 to be described later may include a wavelength conversion layer WCL, thereby displaying a color for each pixel PX. According to some embodiments, the wavelength of light emitted by each light emitting layer EML may be different for each pixel PX.

[0081] The common electrode CME may be arranged on the light emitting layer EML. The common electrode CME may continuously cross the pixels PX. The common electrode CME may be a full-surface electrode arranged across all pixels PX to cover the entire surface. The common electrode CME may be a second electrode (e.g., a cathode electrode) of the light emitting element EMD. The common electrode CME may include a material such as Li, Ca, F, Al, Mg, Ag, Pt, Pd, Ni, Au, Nd, Ir, Cr, Ba, or a compound or mixture thereof (e.g., a mixture of Ag and Mg, LiF, BaF 2 The common electrode CME may further include a transparent metal oxide layer on the material layer having a low work function.

[0082] The thin film encapsulation layer TFEL may be located on the common electrode CME. The thin film encapsulation layer TFEL may include a first inorganic layer TFE1, an organic layer TFE2, and a second inorganic layer TFE3.

[0083] The first inorganic layer TFE1 may be located on the light emitting element EMD. The first inorganic layer TFE1 may include silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y )wait.

[0084] The organic layer TFE2 may be on the first inorganic layer TFE1. The organic layer TFE2 may include an organic insulating material selected from the group consisting of acrylic resin, epoxy resin, phenolic resin, polyamide resin, polyimide resin, unsaturated polyester resin, polyphenylene ether resin, polyphenylene sulfide resin, and benzocyclobutene (BCB).

[0085] The second inorganic layer TFE3 may be located on the organic layer TFE2. The second inorganic layer TFE3 may include the same material as the first inorganic layer TFE1 described above. For example, the second inorganic layer TFE3 may include silicon nitride (SiN x ), silicon oxide (SiO x ), silicon oxynitride (SiO x N y )wait.

[0086] The color conversion substrate 2 may be arranged to face the display substrate 1 above the thin film encapsulation layer TFEL. For example, the color conversion substrate 2 may be positioned to face the display substrate 1 with the filler 3 interposed therebetween.

[0087] The color conversion substrate 2 may include a second base substrate SUB2 , a light blocking member BML, a color filter layer CFL, a first capping layer CAP1 , a partition wall PTL, a wavelength conversion layer WCL, and a second capping layer CAP2 .

[0088] The second base substrate SUB2 may include a transparent material. For example, the second base substrate SUB2 may include a transparent insulating material such as glass, quartz, etc. The second base substrate SUB2 may be a rigid substrate. However, the second base substrate SUB2 is not limited thereto. The second base substrate SUB2 may include a plastic such as polyimide, etc., and may have a flexible property so that it can be twisted, bent, folded, or curled.

[0089] The second base substrate SUB2 may be the same substrate as the first base substrate SUB1, but may have different materials, thicknesses, transmittances, etc. For example, the second base substrate SUB2 may have a higher transmittance than the first base substrate SUB1. The second base substrate SUB2 may be thicker or thinner than the first base substrate SUB1.

[0090] The light blocking member BML may be arranged along the boundary of the pixel PX on one surface of the second base substrate SUB2 facing the first base substrate SUB1. The light blocking member BML may overlap the pixel defining layer PDL of the display substrate 1. The light blocking member BML may include an opening exposing one surface of the second base substrate SUB2, and may be formed in a lattice shape in a plan view.

[0091] The light blocking member BML may include an organic material. The light blocking member BML may reduce color distortion caused by external light reflection by absorbing external light. In addition, the light blocking member BML may be used to prevent or reduce the situation where light emitted from the light emitting layer EML enters the adjacent pixel PX.

[0092] The color filter layer CFL may be located on one surface of the second base substrate SUB2 on which the light blocking member BML is located. The color filter layer CFL may be located on one surface of the second base substrate SUB2 exposed by the opening of the light blocking member BML. In some embodiments, the color filter layer CFL may be formed using an inkjet printing device 10 (see FIG. 1 ) which will be described in more detail later. Figure 5 ) to form.

[0093] The color filter layer CFL may include a colorant such as a dye or a pigment that absorbs wavelengths other than the corresponding color wavelength. The color filter layer CFL may include colorants of different colors for each pixel PX. For example, the color filter layer CFL may include a red colorant, a green colorant, and a blue colorant.

[0094] The first capping layer CAP1 may be located on the color filter layer CFL. The first capping layer CAP1 may prevent or reduce penetration of foreign matter such as moisture, air, etc. In addition, the first capping layer CAP1 may prevent or reduce diffusion of a colorant of the color filter layer CFL into other components.

[0095] The partition wall PTL may be located on the first capping layer CAP1. The partition wall PTL may be arranged to overlap the light blocking member BML. The partition wall PTL may include an opening exposing a region where the color filter layer CFL is located. The partition wall PTL may include a photosensitive organic material, but is not limited thereto according to an embodiment of the present disclosure. The partition wall PTL may also include a light blocking material.

[0096] The wavelength conversion layer WCL may be located in the space exposed by the opening of the partition wall PTL. According to some embodiments, the wavelength conversion layer WCL may be printed using an inkjet printing device 10 (see FIG. 1 ) which will be described in more detail later. Figure 5 ) to form.

[0097] The wavelength conversion layer WCL may convert the wavelength of light incident from the light emitting layer EML. The wavelength conversion layer WCL may include a base resin BRS, and a scatterer SCP and a wavelength conversion material WCP located in the base resin BRS.

[0098] The base resin BRS may include a light-transmitting organic material. For example, the base resin BRS may include epoxy resin, acrylic resin, cardo resin, or imide resin.

[0099] The wavelength conversion material WCP may be a material that converts color. The wavelength conversion material WCP may be a quantum dot, a quantum rod, a phosphor, etc. Examples of quantum dots may include group IV nanocrystals, group II-VI compound nanocrystals, group III-V compound nanocrystals, group IV-VI compound nanocrystals, and combinations thereof.

[0100] According to some embodiments, the wavelength conversion layer WCL may not include the wavelength conversion material WCP. When the wavelength conversion layer WCL does not include the wavelength conversion material WCP, it may function as a light-transmitting layer that transmits light.

[0101] The scatterer SCP may be metal oxide particles or organic particles. Examples of metal oxides may include titanium oxide (TiO 2 )、ZrO 2 ), aluminum oxide (Al 2 O 3 ), indium oxide (In 2 O 3 )、ZnO、SnO 2) etc. Examples of the material of the organic particles may include acrylic resin, polyurethane resin, and the like.

[0102] The second capping layer CAP2 may be located on the wavelength conversion layer WCL and the partition wall PTL. The second capping layer CAP2 may be arranged on the entire surface of the color conversion substrate 2. The second capping layer CAP2 may prevent or reduce the penetration of foreign matter or contaminants such as moisture, air, etc. The second capping layer CAP2 may be made of an inorganic material. The second capping layer CAP2 may include a material selected from the above-mentioned materials of the first capping layer CAP1. The second capping layer CAP2 and the first capping layer CAP1 may be made of the same material, but are not limited thereto.

[0103] The filler 3 may be located between the display substrate 1 and the color conversion substrate 2. The filler 3 may fill the space between the display substrate 1 and the color conversion substrate 2 and may be used to bond them to each other. The filler 3 may be located between the thin film encapsulation layer TFEL of the display substrate 1 and the second capping layer CAP2 of the color conversion substrate 2. The filler 3 may be formed of a Si-based organic material, an epoxy-based organic material, etc., but is not limited thereto according to an embodiment of the present disclosure.

[0104] Figure 4 is a diagram showing an equivalent circuit of a circuit layer according to some embodiments.

[0105] refer to Figure 4 The circuit layer CCL may include various wirings for driving the light emitting element EMD. According to some embodiments, the circuit layer CCL may include a pixel circuit included in each pixel PX, a first voltage line VDL, an initialization voltage line VIL, first and second gate lines GL1 and GL2, a data line DL, and a second voltage line VSL.

[0106] The pixel PX may include a pixel circuit and a light emitting element EMD. The pixel circuit may be connected to a first voltage line VDL, an initialization voltage line VIL, a first gate line GL1, a second gate line GL2, a data line DL, and a second voltage line VSL.

[0107] The first voltage line VDL can provide a driving voltage or a high potential voltage to the pixel circuit. The initialization voltage line VIL can provide an initialization voltage to the pixel circuit. The initialization voltage line VIL can receive a sensing signal from the pixel circuit. The second voltage line VSL can provide a low potential voltage to the light emitting element EMD. The first gate line GL1 can provide a first gate signal to the pixel circuit. The second gate line GL2 can provide a second gate signal to the pixel circuit. The data line DL can provide a data voltage to the pixel circuit.

[0108] The pixel circuit may include a first transistor ST1 , a second transistor ST2 , a third transistor ST3 , and a first capacitor C1 .

[0109] The first transistor ST1 may include a gate electrode, a drain electrode, and a source electrode. The gate electrode of the first transistor ST1 may be connected to the first node N1, the drain electrode thereof may be connected to the first voltage line VDL, and the source electrode thereof may be connected to the second node N2. The first transistor ST1 may control a drain-source current (or a driving current) based on a data voltage applied to the gate electrode. The first transistor ST1 may be a driving transistor for driving the light emitting element EMD.

[0110] The light emitting element EMD can emit light by receiving a driving current. The light emission or brightness of the light emitting element EMD can be proportional to the size of the driving current. The light emitting element EMD can be an organic light emitting diode (OLED) having an organic light emitting layer, a quantum dot light emitting diode (LED) including a quantum dot light emitting layer, a micro LED, or an inorganic LED having an inorganic semiconductor.

[0111] A first electrode of the light emitting element EMD may be connected to the second node N2, and a second electrode of the light emitting element EMD may be connected to the second voltage line VSL. The first electrode of the light emitting element EMD may be connected to the source electrode of the first transistor ST1, the drain electrode of the third transistor ST3, and the second capacitor electrode of the first capacitor C1 through the second node N2.

[0112] The second transistor ST2 may be turned on by the first gate signal of the first gate line GL1 to electrically connect the data line DL to the first node N1 as the gate electrode of the first transistor ST1. The second transistor ST2 may be turned on based on the first gate signal to provide a data voltage to the first node N1. The gate electrode of the second transistor ST2 may be connected to the first gate line GL1, the drain electrode thereof may be connected to the data line DL, and the source electrode thereof may be connected to the first node N1. The source electrode of the second transistor ST2 may be connected to the gate electrode of the first transistor ST1 and the first capacitor electrode of the first capacitor C1 through the first node N1. The second transistor ST2 may be a switching transistor for controlling a current flowing through the first transistor ST1 and the light emitting element EMD.

[0113] The third transistor ST3 may be turned on by the second gate signal of the second gate line GL2 to electrically connect the initialization voltage line VIL to the second node N2 as the source electrode of the first transistor ST1. The third transistor ST3 may be turned on according to the second gate signal to provide the initialization voltage to the second node N2. The third transistor ST3 may be turned on according to the second gate signal to provide the sensing signal to the initialization voltage line VIL. The gate electrode of the third transistor ST3 may be connected to the second gate line GL2, the drain electrode thereof may be connected to the second node N2, and the source electrode thereof may be connected to the initialization voltage line VIL. The drain electrode of the third transistor ST3 may be connected to the source electrode of the first transistor ST1, the second capacitor electrode of the first capacitor C1, and the first electrode of the light emitting element EMD through the second node N2. The third transistor ST3 may be a switching transistor for controlling the current flowing through the first transistor ST1 and the light emitting element EMD.

[0114] The first capacitor C1 may include a first capacitor electrode and a second capacitor electrode. The first capacitor electrode may be connected to the gate electrode of the first transistor ST1 and the source electrode of the second transistor ST2 through a first node N1. The second capacitor electrode may be connected to the source electrode of the first transistor ST1 and the first electrode of the light emitting element EMD through a second node N2. The second capacitor electrode may be connected to the drain electrode of the third transistor ST3. The first capacitor C1 may store capacitance using a voltage difference between the first capacitor electrode and the second capacitor electrode.

[0115] Among various patterns of the display device DD, for example, layers such as the light emitting layer EML, the color filter layer CFL, and the wavelength conversion layer WCL may be printed using an inkjet printing apparatus 10 (see Figure 5 ) is formed. Hereinafter, the inkjet printing device 10 for forming such a pattern will be described in more detail (see Figure 5 ).

[0116] Figure 5 is a cross-sectional view illustrating a state in which an inkjet printing apparatus according to some embodiments performs a printing process.

[0117] refer to Figure 5 , the inkjet printing device 10 can perform a printing process. The printing process may refer to a process of forming a specific pattern on an object using ink or the like. For example, as described above, when the inkjet printing device 10 is used to manufacture a display device DD (see Figure 1 ), the printing process may refer to forming a display device DD (see Figure 1 ) in various patterns (for example, such as the light-emitting layer EML (see Figure 3 ), color filter layer CFL (see Figure 3 ) and wavelength conversion layer WCL (see Figure 3) layer) process.

[0118] The inkjet printing apparatus 10 may include a stage 100 , an ink supply apparatus 200 , a buffer circulation system 300 , a supply circulation system 400 , an inkjet head 500 , and a discharge circulation system 600 .

[0119] The stage 100 may provide a space for mounting a target substrate S. Here, the target substrate S may be the above-mentioned display device DD (see Figure 1 ). The stage 100 may have a flat plate shape. The planar shape of the stage 100 may be similar to the planar shape of the target substrate S. For example, the planar shape of the stage 100 may be a substantially rectangular shape in a plan view, but embodiments according to the present disclosure are not limited thereto, and the stage 100 may have any suitable shape in a plan view.

[0120] According to some embodiments, the stage 100 may move in the first direction DR1 and / or the second direction DR2. According to some embodiments, the inkjet printing apparatus 10 may further include a separate driver for providing a driving force to the stage 100. When a separate driver for providing a driving force to the stage 100 is further included, the inkjet head 500 may eject the ink I to the target substrate S while the stage 100 moves instead of the inkjet head 500. However, embodiments according to the present disclosure are not limited thereto, and both the stage 100 and the inkjet head 500 may move.

[0121] The ink supply device 200 may store the ink I and supply the stored ink I to the buffer circulation system 300. The ink I as a solution may include a solute and a solvent that dissolves the solute. Figure 1 ) structure, solutions and solutes can contain different materials.

[0122] The ink supply device 200 may include an initial supply channel 210. The initial supply channel 210 may connect the ink supply device 200 and the buffer circulation system 300. The ink I of the ink supply device 200 may move to the buffer circulation system 300 through the initial supply channel 210.

[0123] According to some embodiments, a pump located in the initial supply channel 210 may be further included. The pump may provide a driving force so that some of the ink I stored in the ink supply device 200 may move to the buffer circulation system 300 through the initial supply channel 210. The pump may be a fluid pump that transfers power to a fluid such as ink I.

[0124] In some embodiments, the ink supply device 200 may supply the ink I to the inkjet head 500 through an ink storage device, rather than directly supplying the ink I to the inkjet head 500. The ink storage device may include a buffer storage device 310 of the buffer circulation system 300 and a supply storage device 410 of the supply circulation system 400.

[0125] The buffer circulation system 300 may be a buffer circulation system for preventing or reducing ink particles of the ink I from being precipitated in the inkjet printing apparatus 10 and removing bubbles generated in the ink I.

[0126] The buffer circulation system 300 may include a buffer storage device 310 , a first buffer channel 320 , a second buffer channel 330 , and a first pump P1 .

[0127] The buffer storage device 310 may temporarily store the ink I of the ink supply device 200 before the ink I moves to the supply circulation system 400 .

[0128] The first buffer channel 320 may connect the buffer storage device 310 and the supply circulation system 400. At least some of the ink I of the buffer storage device 310 may move to the supply circulation system 400 through the first buffer channel 320.

[0129] The second buffer channel 330 may connect the first buffer channel 320 and the buffer storage device 310. At least some of the ink I of the first buffer channel 320 may be returned to the buffer storage device 310 through the second buffer channel 330. Therefore, the negative pressure of the supply circulation system 400 and the flow rate of the ink I in the supply circulation system 400 may be maintained at a constant level. In addition, even when the ink I is not ejected for a long time, the ink I may be continuously circulated to prevent or reduce the situation where ink particles are deposited in the buffer circulation system 300.

[0130] The first pump P1 may provide a driving force so that some of the ink I stored in the buffer storage device 310 may move to the supply circulation system 400 through the first buffer channel 320. In addition, the first pump P1 may provide a driving force so that some of the ink I moving along the first buffer channel 320 may return to the buffer storage device 310. For example, the first pump P1 may be a fluid pump that transmits power to a fluid such as ink I.

[0131] In some embodiments, the first pump P1 may include a plurality of pumps. For example, the first pump P1 may include a first sub-pump that provides a driving force so that some of the ink I stored in the buffer storage device 310 can move to the supply circulation system 400 through the first buffer channel 320, and a second sub-pump that provides a driving force so that some of the ink I moving along the first buffer channel 320 can return to the buffer storage device 310.

[0132] The supply circulation system 400 may be a supply circulation system for supplying the ink I to the inkjet head 500 in the inkjet printing apparatus 10 by providing negative pressure.

[0133] The supply circulation system 400 may include a supply storage device 410 , a supply channel 420 , a branch point 430 , a pressure regulator 440 , a second pump P2 , one or more supply valves V1 and V2 , and one or more supply manifolds M1 and M2 .

[0134] The supply storage device 410 may store the ink I of the buffer storage device 310 before the ink I moves to the inkjet head 500 .

[0135] The supply channel 420 may include one or more supply channels 421, 422, and 423. For example, the supply channel 420 may include a first supply channel 421, a second supply channel 422, and a third supply channel 423. The branch point 430 may include at least one branch point. However, the number of supply channels 420 and the number of branch points 430 are not limited thereto, and may be variously changed according to the number of inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0136] The first supply channel 421 may connect the supply storage device 410 and the branch point 430. The branch point 430 may be a branch point at which the first supply channel 421 branches into the second supply channel 422 and the third supply channel 423.

[0137] The second supply channel 422 may connect the branch point 430 and the first manifold M1. The third supply channel 423 may connect the branch point 430 and the second manifold M2. The second supply channel 422 and the third supply channel 423 may supply the ink I to the first inkjet head 510 and the second inkjet head 520, respectively.

[0138] The pressure regulator 440 may provide negative pressure to the supply circulation system 400. For example, the pressure regulator 440 may be a vacuum regulator or an air regulator. The pressure regulator 440 may provide negative pressure to the supply circulation system 400 so that the ink I in the nozzles NZ of the inkjet head 500 may form a meniscus. In addition, the ink I in the nozzles NZ of the inkjet head 500 may be prevented or reduced from being ejected randomly due to gravity.

[0139] The second pump P2 may provide a driving force so that the ink I stored in the supply storage device 410 moves to the inkjet head 500 through the supply channel 420. For example, the second pump P2 may be a fluid pump that transmits power to the fluid such as the ink I.

[0140] The supply valves V1 and V2 may control whether the ink I flows in the supply channel 420. According to some embodiments, the supply valves V1 and V2 may be on / off valves. For example, when the supply valves V1 and V2 are open, the ink I may pass through the supply channel 420, and when the supply valves V1 and V2 are closed, the ink I may not pass through the supply channel 420.

[0141] According to some embodiments, the supply valves V1 and V2 may include a first valve V1 and a second valve V2. The first valve V1 may be located in the second supply channel 422 to control whether the ink I flows in the second supply channel 422. The second valve V2 may be located in the third supply channel 423 to control whether the ink I flows in the third supply channel 423. However, the number of the supply valves V1 and V2 is not limited thereto, and may be variously changed according to the number of the inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0142] The supply manifolds M1 and M2 may supply the ink I to each inlet IL of the inkjet head 500. For example, the supply manifolds M1 and M2 may branch the supply channel 420 into one or more sub-supply channels SSL respectively connected to the one or more inlets IL.

[0143] According to some embodiments, the supply manifolds M1 and M2 may include a first manifold M1 and a second manifold M2. The first manifold M1 may be connected to the second supply channel 422 to supply the ink I to one or more inlets IL of the first inkjet head 510. The second manifold M2 may be connected to the third supply channel 423 to supply the ink I to one or more inlets IL of the second inkjet head 520. However, the number of the supply manifolds M1 and M2 is not limited thereto and may be variously changed according to the number of the inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0144] The inkjet head 500 may be located on the stage 100. The inkjet head 500 may eject ink I toward the stage 100. The ink I ejected from the inkjet head 500 may be deposited on a target substrate S placed on the stage 100.

[0145] In some embodiments, the inkjet head 500 may move in the first direction DR1 and / or the second direction DR2. According to some embodiments, the inkjet printing apparatus 10 may further include a separate driver for providing a driving force to the inkjet head 500. If a separate driver for providing a driving force to the inkjet head 500 is further included, the inkjet head 500 may move instead of the stage 100 to eject the ink I onto the target substrate S. However, embodiments according to the present disclosure are not limited thereto, and both the stage 100 and the inkjet head 500 may move.

[0146] The inkjet head 500 may include at least one inlet IL, at least one outlet OL, and at least one nozzle NZ.

[0147] The inlet IL may be an inlet through which the ink I enters the inkjet head 500. One or more inlets IL may be connected to each of the supply manifolds M1 and M2. The ink I supplied from the supply manifolds M1 and M2 may be ejected onto the stage 100 through the nozzles NZ, or may be moved to the discharge circulation system 600 through the outlet OL.

[0148] The nozzles NZ may face the stage 100. The ink I supplied from the inlet IL may be ejected onto the stage 100 through at least one nozzle NZ.

[0149] The outlet OL may be an outlet through which the ink I is discharged from the inkjet head 500. One or more outlets OL may be connected to each of the discharge manifolds M3 and M4. The ink I remaining in the inkjet head 500 without being ejected through the nozzles NZ may move to the discharge manifolds M3 and M4 through the outlet OL.

[0150] According to some embodiments, the inkjet head 500 may include a first inkjet head 510 and a second inkjet head 520. The first inkjet head 510 and the second inkjet head 520 may be arranged along the first direction DR1 or the second direction DR2. As shown in the figure, the first inkjet head 510 and the second inkjet head 520 may be arranged to be spaced apart from each other, but are not limited thereto according to embodiments of the present disclosure. Although the case where the number of inkjet heads 500 is two is described as an example, embodiments of the present disclosure are not limited thereto, and the number of inkjet heads 500 may vary.

[0151] The discharge circulation system 600 may be a discharge circulation system for reusing the ink I remaining in the inkjet head 500 without being ejected through the nozzles NZ.

[0152] The exhaust circulation system 600 may include an exhaust passage 610 , a junction 620 , one or more exhaust valves V3 and V4 , and one or more exhaust manifolds M3 and M4 .

[0153] The discharge manifolds M3 and M4 may discharge the ink I from each outlet OL of the inkjet head 500. For example, the discharge manifolds M3 and M4 may combine one or more sub discharge channels SOL connected to one or more outlets OL into the discharge channel 610.

[0154] According to some embodiments, the discharge manifolds M3 and M4 may include a third manifold M3 and a fourth manifold M4. The third manifold M3 may be connected to the first discharge channel 611 to discharge the ink I from the outlet OL of the first inkjet head 510. The fourth manifold M4 may be connected to the second discharge channel 612 to discharge the ink I from the outlet OL of the second inkjet head 520. However, the number of the discharge manifolds M3 and M4 is not limited thereto, and may be variously changed according to the number of the inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0155] The discharge channel 610 may include one or more discharge channels 611, 612, and 613. For example, the discharge channel 610 may include a first discharge channel 611, a second discharge channel 612, and a third discharge channel 613. The junction 620 may include at least one junction. However, the number of the discharge channels 610 and the number of the junctions 620 are not limited thereto, and may be variously changed according to the number of the inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0156] The first exhaust passage 611 may connect the junction point 620 and the third manifold M3. The second exhaust passage 612 may connect the junction point 620 and the fourth manifold M4. The junction point 620 may be a junction point where the first exhaust passage 611 and the second exhaust passage 612 are combined into the third exhaust passage 613.

[0157] The third discharge channel 613 may connect the junction point 620 and the supply storage device 410. Since the third discharge channel 613 re-supplies the ink I to the supply storage device 410, the ink I that is not ejected may be reused.

[0158] The discharge valves V3 and V4 may control whether the ink I flows in the discharge channel 610. According to some embodiments, the discharge valves V3 and V4 may be on / off valves. For example, when the discharge valves V3 and V4 are open, the ink I may pass through the discharge channel 610, and when the discharge valves V3 and V4 are closed, the ink I may not pass through the discharge channel 610.

[0159] According to some embodiments, the one or more discharge valves V3 and V4 may include a third valve V3 and a fourth valve V4. The third valve V3 may be located in the first discharge channel 611 to control whether the ink I flows in the first discharge channel 611. The fourth valve V4 may be located in the second discharge channel 612 to control whether the ink I flows in the second discharge channel 612. However, the number of the discharge valves V3 and V4 is not limited thereto, and may be variously changed according to the number of the inkjet heads 500 and the design structure of the inkjet printing apparatus 10.

[0160] In the discharge circulation system 600, the ink I may be moved by the driving force of the supply circulation system 400. For example, the ink I may circulate through the supply circulation system 400, the inkjet head 500, and the discharge circulation system 600 by the driving force of the second pump P2 of the supply circulation system 400.

[0161] Figure 6 is a cross-sectional view illustrating a state in which an inkjet printing apparatus according to some embodiments performs a head care process. Figure 7 is a cross-sectional view illustrating a state in which a head care process is completed in an inkjet printing apparatus according to some embodiments.

[0162] refer to Figure 6 and Figure 7 , the inkjet printing apparatus 10 may perform a head care process. The head care process may refer to a maintenance and repair process performed to maintain printing quality by removing deposits or bubbles formed at the inkjet head 500 and preventing or reducing drying of the ink 1. The head care process may include a cleaning process and a splashing process.

[0163] The purging process may be a process of continuously discharging the ink I to the outside through the nozzles NZ by forcibly pushing the ink I into the inkjet head 500 for the purpose of maintaining printing quality and inspecting the head when replenishing the ink I or in the middle of the printing process.

[0164] The splattering process may be a process of periodically ejecting ink I to the outside of the nozzle NZ when the printing process is idle to prevent or reduce drying of the ink I in the nozzle NZ. According to some embodiments, the inkjet printing apparatus 10 may eject approximately 1 to 10,000 drops of ink I to the outside at intervals of approximately 1 to 600 seconds during the splattering process.

[0165] The inkjet printing apparatus 10 according to some embodiments may reuse the ink I consumed in a head care process such as a cleaning process and a splattering process in a printing process.

[0166] According to some embodiments, the inkjet printing apparatus 10 may further include a storage circulation system 700. The storage circulation system 700 may be a circulation system for reusing the ink I consumed in a head care process such as a cleaning process and a splattering process in a printing process. The storage circulation system 700 may include a cleaning tank 710, a concentration measuring device 720, a solvent supply device 730, a removal tank 740, a storage channel 750, a third pump P3, a fourth pump P4, and a fifth pump P5.

[0167] The cleaning cylinder 710 may be a container for collecting the ink I ejected by the head care process. During the head care process, the cleaning cylinder 710 may be located under the inkjet head 500. According to some embodiments, the cleaning cylinder 710 may have a shape whose width narrows toward the lower portion. For example, the cleaning cylinder 710 may have a reverse trapezoidal shape. However, embodiments according to the present disclosure are not limited thereto, and the shape of the cleaning cylinder 710 may be variously changed.

[0168] According to some embodiments, the inner wall of the washing cylinder 710 may be subjected to super-hydrophobic coating. For example, the inner wall of the washing cylinder 710 may include a super-hydrophobic coating film. Therefore, it is possible to prevent or reduce the situation where the ink I remains on the inner wall of the washing cylinder 710 and does not circulate in the storage circulation system 700. In addition, it is possible to prevent or reduce the situation where deposits are formed on the inner wall of the washing cylinder 710 due to the drying of the ink I.

[0169] In some embodiments, the level H of the ink I in the washing tank 710 may be maintained at a constant level. For example, when the level H of the ink I in the washing tank 710 exceeds a certain level, the third pump P3 may operate to adjust the level H of the ink I in the washing tank 710. Therefore, the distance between the surface of the ink I in the washing tank 710 and the inkjet head 500 may be maintained at a constant distance. When the ink I ejected from the inkjet head 500 falls on the surface of the ink I in the washing tank 710, its splashing to the outside may be prevented or reduced.

[0170] In some embodiments, the cleaning tub 710 may include a door 711. The door 711 may control the opening and closing of the cleaning tub 710. Figure 6 As shown in FIG. 1 , when the head care process is performed, the door 711 can be opened and Figure 7 As shown in , when the head care process is idle, the door 711 can be closed. According to some embodiments, the door 711 can include a separate door driver capable of providing a driving force to the door 711.

[0171] The concentration measurement device 720 may include a densitometer 721 and a filter 722 .

[0172] The densitometer 721 may be located between the cleaning tank 710 and the ink supply device 200. For example, the densitometer 721 may be located in a first storage channel 751 connecting the cleaning tank 710 and the ink supply device 200.

[0173] The densitometer 721 can measure the concentration of the ink I moved from the cleaning tank 710 to the ink supply device 200. The inkjet printing device 10 according to some embodiments includes the densitometer 721 so that the concentration of the ink I can be maintained at a constant level. Therefore, the reliability of the quality of the ink I can be improved. Figures 8 to 10 The specific structure of the densitometer 721 is described.

[0174] The filter 722 may remove impurities contained in the ink I moved from the cleaning tank 710 to the ink supply device 200. For example, if the door 711 of the cleaning tank 710 is opened during the head care process, external contaminants such as dust or other impurities may penetrate into the cleaning tank 710. The filter 722 may prevent or reduce the contaminants such as impurities from moving to the ink supply device 200.

[0175] The filter 722 may be located between the densitometer 721 and the cleaning tub 710. Since the filter 722 removes impurities contained in the ink I flowing into the densitometer 721, the concentration of the ink I may be prevented or reduced from being erroneously measured due to the impurities contained in the ink I.

[0176] The solvent supply device 730 may control the concentration of the ink I in the cleaning tank 710. For example, the solvent supply device 730 may supply a solvent SLV to the cleaning tank 710. The solvent SLV may refer to a liquid component for dissolving a solute contained in the ink I as an example of a solution. As described above, depending on the display device DD to be printed (see Figure 1 ) structure, the solvent SLV can include different materials.

[0177] Due to the characteristics of the printing process, the solvent SLV may have high volatility. Therefore, when the ink I remains or circulates in the inkjet printing apparatus 10 for a certain time or longer, the solvent SLV component of the ink I may volatilize, and the concentration of the ink I may increase. The inkjet printing apparatus 10 according to some embodiments includes a solvent supply device 730 for supplying the solvent SLV to the washing tank 710, so that the concentration of the ink I can be maintained at a constant level.

[0178] The removal tank 740 may be a container for temporarily storing or discharging the contaminated and non-reusable ink I. The removal tank 740 may prevent or reduce the contaminated and non-reusable ink I from flowing into the ink supply device 200 through the first storage channel 751 .

[0179] According to some embodiments, the inkjet printing device 10 includes a separate removal tank 740 to prevent or reduce the contaminated and non-reusable ink I from flowing into the ink supply device 200, the buffer circulation system 300, the supply circulation system 400, the inkjet head 500 and the exhaust circulation system 600, thereby preventing or reducing their contamination.

[0180] The storage channel 750 may include one or more storage channels 751, 752, 753, and 754. For example, the storage channel 750 may include a first storage channel 751, a second storage channel 752, a third storage channel 753, and a fourth storage channel 754.

[0181] The first storage channel 751 may connect the cleaning cylinder 710 and the ink supply device 200. At least some of the ink I in the cleaning cylinder 710 may be moved to the ink supply device 200 through the first storage channel 751. At least some of the ink I moved from the cleaning cylinder 710 to the ink supply device 200 may be returned to the buffer circulation system 300 and the supply circulation system 400 to be reused in the printing process. Therefore, the ink I consumed in the head care process may be reused in the printing process.

[0182] The second storage channel 752 may connect the ink supply device 200 and the cleaning tank 710. At least some of the ink I of the ink supply device 200 may be returned to the cleaning tank 710 through the second storage channel 752. In the inkjet printing device 10 according to some embodiments, a circulation system that circulates the ink supply device 200 and the cleaning tank 710 may be formed by the first storage channel 751 and the second storage channel 752. Therefore, even if the solvent supply device 730 for adjusting the concentration by injecting the solvent SLV is connected to the cleaning tank 710, a constant concentration of the ink I may be maintained even in the ink supply device 200 due to one circulation system in which the ink supply device 200 and the cleaning tank 710 are connected to each other. In addition, the flow rate between the ink supply device 200 and the cleaning tank 710 is maintained, so that precipitation of the ink I in the ink supply device 200 and the cleaning tank 710 may be prevented or reduced.

[0183] The third storage channel 753 may connect the solvent supply device 730 and the cleaning tank 710. At least some of the solvent SLV of the solvent supply device 730 may move to the cleaning tank 710 through the third storage channel 753. Therefore, the concentration of the ink I in the cleaning tank 710 and the ink supply device 200 may be maintained at a constant level.

[0184] The fourth storage channel 754 may connect the cleaning cylinder 710 and the removal tank 740. At least some of the ink I in the cleaning cylinder 710 (e.g., the ink I that is contaminated and cannot be reused) may be moved to the removal tank 740 through the fourth storage channel 754. The inkjet printing apparatus 10 according to some embodiments includes a separate fourth storage channel 754 that is not connected to the ink supply apparatus 200, so that the contaminated and cannot be reused ink I is prevented or reduced from flowing into the ink supply apparatus 200, the buffer circulation system 300, the supply circulation system 400, the inkjet head 500, and the exhaust circulation system 600, thereby preventing or reducing contamination thereof.

[0185] The third pump P3 may provide driving force so that the ink I collected in the cleaning cylinder 710 may move to the ink supply device 200 through the first storage channel 751. For example, the third pump P3 may be a fluid pump that transmits power to the fluid such as the ink I.

[0186] The fourth pump P4 may provide driving force so that the solvent SLV of the solvent supply device 730 may move to the washing tub 710 through the third storage channel 753. For example, the fourth pump P4 may be a fluid pump that transmits power to a fluid such as the solvent SLV.

[0187] The fifth pump P5 may provide driving force so that the contaminated and non-reusable ink I in the washing cylinder 710 may be moved to the removal tank 740 through the fourth storage channel 754. For example, the fifth pump P5 may be a fluid pump that transmits power to a fluid such as ink I.

[0188] In some embodiments, the fourth pump P4 and / or the solvent supply device 730 may receive a driving signal DS from the densitometer 721. The fourth pump P4 and / or the solvent supply device 730 may supply a required amount of solvent SLV to the washing tank 710 based on the driving signal DS. In the inkjet printing apparatus 10 according to some embodiments, the fourth pump P4 and / or the solvent supply device 730 may automatically supply the solvent SLV to the washing tank 710 by the driving signal DS provided from the densitometer 721. Therefore, process efficiency may be improved, and reliability of the quality of the ink I may be improved.

[0189] Figure 8 yes Figure 6 Magnified view of area B. Fig. 9 is a schematic block diagram illustrating a densitometer according to some embodiments. Fig.10 is a schematic block diagram illustrating a densitometer according to some embodiments.

[0190] Apart from Figure 6 In addition, reference Figures 8 to 10In some embodiments, the densitometer 721 may include a measurement source generator 721a, a measurement source detector 721b, and a controller 721c.

[0191] The measurement source generator 721a may generate the measurement source Z1. The measurement source Z1 generated from the measurement source generator 721a may be detected by the measurement source detector 721b after the measurement source Z1 interacts with the ink I in the first storage channel 751. The measurement source generator 721a may provide a generation signal GS including information about the generated measurement source Z1 to the controller 721c.

[0192] The measurement source detector 721b may detect the measurement source Z1 interacting with the ink I in the first storage channel 751. The measurement source detector 721b may provide a sensing signal SS including information about the detected measurement source Z1 to the controller 721c.

[0193] The controller 721c may measure the concentration of the ink I by comparing the information about the measurement source Z1 included in the generation signal GS with the information about the measurement source Z1 included in the sensing signal SS. When the measured concentration of the ink I is different from the reference value, the controller 721c may provide a driving signal DS to the fourth pump P4 and / or the solvent supply device 730.

[0194] The fourth pump P4 receiving the driving signal DS may provide driving force so that the solvent SLV of the solvent supply device 730 may move to the washing tub 710. The solvent supply device 730 receiving the driving signal DS may supply the solvent SLV to the washing tub 710.

[0195] According to some embodiments, the densitometer 721 may include an optical densitometer. Figure 8 As shown in , when the densitometer 721 includes an optical densitometer, the measuring source generator 721a and the measuring source detector 721b can be located on opposite sides, and the first storage channel 751 is interposed therebetween. The measuring source generator 721a can irradiate light as the measuring source Z1 toward the measuring source detector 721b. When the light as the measuring source Z1 passes through the ink I, the inherent energy such as brightness can be reduced according to the concentration of the ink I. The measuring source detector 721b can measure the inherent energy of the light passing through the ink I. The controller 721c can measure the concentration of the ink I by comparing the inherent energy value of the light originally generated by the measuring source generator 721a with the inherent energy value of the light detected by the measuring source detector 721b.

[0196] According to some embodiments, the densitometer 721 may include an acoustic wave type densitometer. Fig. 9As shown in , when the densitometer 721 includes an acoustic wave type densitometer, the measuring source generator 721a and the measuring source detector 721b can be integrated. However, the embodiments according to the present disclosure are not limited thereto, and the measuring source generator 721a and the measuring source detector 721b can be configured separately, but can be located on the same side relative to the first storage channel 751. The measuring source generator 721a can emit acoustic waves as the measuring source Z1 toward the ink I in the first storage channel 751. When the acoustic wave as the measuring source Z1 is reflected by the ink I, the inherent energy such as the amplitude can be reduced according to the concentration of the ink I. The measuring source detector 721b can measure the inherent energy of the acoustic wave reflected by the ink I. The controller 721c can measure the concentration of the ink I by comparing the inherent energy value of the acoustic wave originally generated by the measuring source generator 721a with the inherent energy value of the acoustic wave detected by the measuring source detector 721b.

[0197] According to some embodiments, the densitometer 721 may include an electronic densitometer. Fig.10 As shown in , when the densitometer 721 includes an electronic densitometer, the measurement source generator 721a and the measurement source detector 721b can be integrated. The measurement source generator 721a can apply a voltage to the ink I in the first storage channel 751 so that a current as a measurement source Z1 can flow. The size of the resistance or the intensity of the current as the measurement source Z1 can be different according to the concentration of the ink I. The measurement source detector 721b can measure the size of the resistance or the intensity of the current flowing through the ink I. The controller 721c can measure the concentration of the ink I by comparing the voltage generated by the measurement source generator 721a with the size of the resistance or the intensity of the current detected by the measurement source detector 721b.

[0198] The inkjet printing apparatus 10 according to some embodiments includes the densitometer 721 so that the concentration of the ink I can be maintained at a constant level. Therefore, the reliability of the quality of the ink I can be improved. In addition, the fourth pump P4 and / or the solvent supply device 730 can automatically supply the solvent SLV to the washing tank 710 in response to the driving signal DS provided from the densitometer 721. Therefore, the process efficiency can be improved.

[0199] Hereinafter, aspects of the inkjet printing apparatus according to some embodiments will be described in more detail. In the following embodiments, descriptions of components identical to those in the above embodiments may be omitted or simplified, are denoted by the same reference numerals, and differences will be mainly described.

[0200] Fig.11 is a cross-sectional view of an inkjet printing apparatus according to some embodiments.

[0201] refer to Fig.11The inkjet printing device 10 according to this embodiment is different from the one described in reference Figure 6 The inkjet printing apparatus 10 according to some embodiments described in , etc. is different in that a solvent supply apparatus 730 is connected to the ink supply apparatus 200 .

[0202] More specifically, the solvent supply device 730 may adjust the concentration of the ink I in the ink supply device 200. For example, the solvent supply device 730 may supply the solvent SLV to the ink supply device 200. The inkjet printing apparatus 10 according to some embodiments includes the solvent supply device 730 for supplying the solvent SLV to the ink supply device 200 so that the concentration of the ink I can be maintained at a constant level.

[0203] The second storage channel 752 may connect the ink supply device 200 and the cleaning tank 710. At least some of the ink I of the ink supply device 200 may be returned to the cleaning tank 710 through the second storage channel 752. In the inkjet printing device 10 according to some embodiments, a circulation system that circulates the ink supply device 200 and the cleaning tank 710 may be formed by the first storage channel 751 and the second storage channel 752. Therefore, even if the solvent supply device 730 for adjusting the concentration by injecting the solvent SLV is connected to the ink supply device 200, a constant concentration of the ink I may be maintained even in the cleaning tank 710 due to one circulation system in which the ink supply device 200 and the cleaning tank 710 are connected to each other. In addition, the flow rate between the ink supply device 200 and the cleaning tank 710 is maintained at a constant level, so that precipitation of the ink I in the ink supply device 200 and the cleaning tank 710 may be prevented or reduced.

[0204] The third storage channel 753 may connect the solvent supply device 730 and the ink supply device 200. At least some of the solvent SLV of the solvent supply device 730 may move to the ink supply device 200 through the third storage channel 753. Therefore, the concentration of the ink I in the cleaning tank 710 and the ink supply device 200 may be maintained at a constant level.

[0205] The fourth pump P4 may provide a driving force so that the solvent SLV of the solvent supply device 730 may move to the ink supply device 200 through the third storage channel 753 .

[0206] In some embodiments, the fourth pump P4 and / or the solvent supply device 730 may receive a driving signal DS from the densitometer 721. The fourth pump P4 and / or the solvent supply device 730 may supply a required amount of solvent SLV to the ink supply device 200 based on the driving signal DS. In the inkjet printing apparatus 10 according to some embodiments, the fourth pump P4 and / or the solvent supply device 730 may automatically supply the solvent SLV to the ink supply device 200 by the driving signal DS provided from the densitometer 721. Therefore, process efficiency may be improved.

[0207] Although it is shown in reference Figure 6 In the inkjet printing apparatus 10 according to some embodiments described, the solvent supply device 730 is connected to the cleaning tank 710, and in the inkjet printing apparatus 10 according to the present embodiment, the solvent supply device 730 is connected to the ink supply device 200, but the embodiments according to the present disclosure are not limited thereto. For example, the solvent supply device 730 may be connected to both the cleaning tank 710 and the ink supply device 200. For another example, the solvent supply device 730 may be connected to at least one of the first storage channel 751 and the second storage channel 752.

[0208] Fig.12 is a bottom view showing an inkjet head of an inkjet printing apparatus according to some embodiments. Fig.13 and Fig.14 is a cross-sectional view of an inkjet printing apparatus according to some embodiments.

[0209] refer to Figure 12 to Figure 14 The inkjet printing device 10 according to this embodiment is different from the one described in reference Figure 6 The inkjet printing apparatus 10 according to some embodiments described in is different in that it can be used in a squeegee wiping process as a head care process.

[0210] More specifically, if Fig.12 As shown in the figure, the inkjet head 500 may include a plurality of nozzles NZ spaced apart from each other in the first direction DR1 or the second direction DR2. Although the plurality of nozzles NZ are shown in the drawings as being arranged in a row while being spaced apart from each other in the first direction DR1, embodiments according to the present disclosure are not limited thereto. For example, the plurality of nozzles NZ may include a plurality of rows spaced apart from each other in the second direction DR2, and tens to thousands of nozzles NZ may be arranged in each row in the first direction DR1. The number and arrangement of the plurality of nozzles NZ are not limited to those shown in the drawings.

[0211] After a printing process or after a head care process such as a cleaning process and a splattering process, residual ink IRS may remain on the bottom surface 500a of the inkjet head 500. For example, the residual ink IRSa may include a first residual ink IRSa remaining in the nozzles NZ and a second residual ink IRSb remaining on the bottom surface 500a of the inkjet head 500. When they remain for a long time, the first residual ink IRSa may mainly cause clogging of the nozzles NZ, and the second residual ink IRSb may mainly cause contamination of the inkjet head 500.

[0212] Due to the head care process (such as the cleaning process and the splashing process), the first residual ink IRSa remaining in the nozzle NZ can be removed, or the situation where the first residual ink IRSa is preformed can be prevented or reduced. However, the second residual ink IRSb remaining on the bottom surface 500a of the inkjet head 500 may not be easily removed even through the cleaning process and the splashing process.

[0213] Therefore, the squeegee wiping process can also be performed as a head care process of the inkjet printing apparatus 10. Fig.13 and Fig.14 As shown in FIG. 1 , the blade wiping process refers to a process of wiping the bottom surface 500 a of the inkjet head 500 using a blade BLD to push and remove the residual ink IRS.

[0214] The inkjet printing apparatus 10 according to some embodiments can reuse the residual ink IRS removed in the scraper wiping process through the storage circulation system 700. For example, the residual ink IRS removed from the bottom surface 500a of the inkjet head 500 using the scraper BLD can be collected in the cleaning tank 710. Figure 6 As in the described inkjet printing apparatus 10 according to some embodiments, the residual ink IRS collected in the cleaning tank 710 can be reused in the printing process through the storage circulation system 700.

[0215] Fig.15 and Fig.16 is a cross-sectional view of an inkjet printing apparatus according to some embodiments.

[0216] Apart from Fig.12 In addition, reference Fig.15 and Fig.16 The inkjet printing device 10 according to this embodiment is different from the inkjet printing device 10 according to the reference Figure 6 The inkjet printing apparatus 10 of the embodiment described above is different in that it can be used in a suction process as a head care process.

[0217] More specifically, as mentioned above Fig.12As described, after the printing process or after the head care process such as the cleaning process and the splattering process, the residual ink IRS may remain on the bottom surface 500a of the inkjet head 500. For example, the residual ink IRSa may include the first residual ink IRSa remaining in the nozzles NZ and the second residual ink IRSb remaining on the bottom surface 500a of the inkjet head 500. When they remain for a long time, the first residual ink IRSa may mainly cause clogging of the nozzles NZ, and the second residual ink IRSb may mainly cause contamination of the inkjet head 500.

[0218] Due to the head care process (such as the cleaning process and the splashing process), the first residual ink IRSa remaining in the nozzle NZ can be removed, or the situation where the first residual ink IRSa is preformed can be prevented or reduced. However, some of the first residual ink IRSa may remain in the nozzle NZ, and the second residual ink IRSb remaining on the bottom surface 500a of the inkjet head 500 may not be easily removed even through the cleaning process and the splashing process.

[0219] Therefore, the suction process can also be performed as a head care process of the inkjet printing device 10. Fig.15 and Fig.16 As shown in , the suction process may be a process of sucking and removing the residual ink IRS using a suction device SUC connected to the suction channel SUCa. For example, the suction device SUC may suck and remove the first residual ink IRSa in the nozzle NZ and the second residual ink IRSb on the bottom surface 500a of the inkjet head 500 through the suction channel SUCa.

[0220] The inkjet printing apparatus 10 according to some embodiments can reuse the residual ink IRS removed in the suction process through the storage circulation system 700. For example, the residual ink IRS removed using the suction device SUC connected to the suction channel SUCa can be collected in the cleaning tank 710. Figure 6 As in the described inkjet printing apparatus 10 according to some embodiments, the residual ink IRS collected in the cleaning tank 710 can be reused in the printing process through the storage circulation system 700.

[0221] In some embodiments, the door 711 of the cleaning cylinder 710 can be closed even during the suction process. For example, the door 711 of the cleaning cylinder 710 may include a suction opening 711_OP communicated with the suction channel SUCa. The suction opening 711_OP of the door 711 may move along the suction channel SUCa. The other parts of the door 711 except the suction opening 711_OP may seal the cleaning cylinder 710. Therefore, impurities infiltrated into the cleaning cylinder 710 may be prevented or reduced. In addition, the drying speed of the ink I may be minimized.

[0222] At the end of the detailed description, it will be appreciated by those skilled in the art that many changes and modifications may be made to the disclosed embodiments without departing substantially from the spirit and scope of the embodiments according to the present disclosure. Therefore, the disclosed embodiments according to the present disclosure are used only in a general and descriptive sense, and not for the purpose of limitation.

Claims

1. Inkjet printing equipment, including: Inkjet head; an ink supply device connected to the inkjet head; a cleaning cylinder, below the inkjet head and connected to the ink supply device; a first channel connecting the cleaning cylinder and the ink supply device; as well as Densitometer, in the first channel.

2. The inkjet printing device according to claim 1, wherein: The density meter comprises: Measurement source generator; a measurement source detector configured to detect a measurement source generated from the measurement source generator; and A controller is configured to receive information about the measurement source from the measurement source detector and the measurement source generator, respectively.

3. The inkjet printing apparatus according to claim 2, wherein: The measurement source generator and the measurement source detector are located on opposite sides, and the first channel is interposed between the measurement source generator and the measurement source detector.

4. The inkjet printing apparatus according to claim 2, wherein: The measurement source generator and the measurement source detector are located on the same side relative to the first channel.

5. The inkjet printing apparatus according to claim 2, wherein: The measurement source generated from the measurement source generator is configured to interact with ink located in the first channel.

6. The inkjet printing apparatus according to claim 5, wherein: The measurement source generator is configured to provide a first signal to the controller containing information about the measurement source generated from the measurement source generator, The measurement source detector is configured to provide a second signal to the controller containing information about the measurement source interacting with the ink, and The controller is configured to generate a third signal based on the first signal and the second signal.

7. The inkjet printing apparatus according to claim 6, further comprising a solvent supply device connected to at least one of the cleaning tank, the first channel, and the ink supply device, in, The controller is configured to provide the third signal to the solvent supply device.

8. The inkjet printing apparatus according to claim 7, wherein: The solvent supply device having received the third signal is configured to supply the solvent of the ink to at least one of the cleaning tank, the first channel, and the ink supply device.

9. The inkjet printing apparatus according to claim 1, further comprising a filter between the densitometer and the cleaning tank.

10. The inkjet printing apparatus according to claim 1, wherein: The washing tub includes a door configured to control opening and closing of the washing tub.

11. The inkjet printing apparatus according to claim 10, wherein: The door includes a door driver configured to provide a driving force to the door.

12. The inkjet printing apparatus according to claim 10, further comprising: a suction channel connecting the inkjet head and the door of the cleaning cylinder; as well as A suction device is connected to the suction channel.

13. The inkjet printing apparatus according to claim 12, wherein: The door includes a suction opening communicating with the suction passage, and The suction opening is configured to move along the suction channel.

14. The inkjet printing apparatus according to claim 1, wherein: The inner wall of the cleaning cylinder includes a super hydrophobic coating film.

15. The inkjet printing apparatus according to claim 1, wherein: The level of ink in the cleaning tank is maintained at a constant level.

16. The inkjet printing apparatus according to claim 1, further comprising a removal tank connected to the cleaning tank, in, The removal tank is not connected to the ink supply device.

17. The inkjet printing device according to claim 1, further comprising a second channel connecting the cleaning tank and the ink supply device and different from the first channel, in, The ink flow directions of the first channel and the second channel are different.

18. The inkjet printing apparatus according to claim 1, further comprising a scraper located between the inkjet head and the cleaning cylinder, in, The scraper is configured to wipe a bottom surface of the inkjet head.

19. Inkjet printing equipment, including: Ink supply equipment; an ink storage device configured to receive ink from the ink supply device; an inkjet head configured to receive the ink from the ink storage device; a cleaning cylinder configured to collect the ink ejected from the inkjet head; a first passage configured to move the ink from the cleaning tank to the ink supply; a densitometer configured to measure a concentration of the ink in the first channel; as well as A solvent supply device is configured to supply a solvent of the ink to at least one of the ink supply device, the cleaning tank, and the first channel.

20. The inkjet printing device of claim 19, further comprising a first pump in the first channel and configured to provide a driving force from the cleaning tank toward the ink supply device.

21. The inkjet printing device of claim 20, further comprising a second passage, the second passage being different from the first passage and configured to move the ink from the ink supply to the purge tank.

22. The inkjet printing apparatus of claim 21, further comprising a third channel configured to move the solvent of the ink from the solvent supply to at least one of the ink supply, the purge tank, and the first channel.

23. The inkjet printing apparatus according to claim 22, further comprising a second pump in the third channel and configured to provide a driving force from the solvent supply device toward at least one of the ink supply device, the cleaning tank, and the first channel.

Images