Inkjet printing device and cleaning method for inkjet printing device

Abstract

To provide an inkjet printing apparatus that can reduce the defect rate of the organic light-emitting layer. [Solution] The inkjet printing apparatus may include a first stage, a second stage on which a substrate is placed, which includes a heater located inside the first stage and includes a print area that overlaps with the heater in a plan view, a housing located on the substrate, a plurality of print heads located inside the housing, a plurality of nozzles located on the underside of each print head, and an ink supply device that supplies ink to the print heads, and a head unit that moves in a first direction, a cleaning unit located on the first stage and moving in a second direction intersecting the first direction, and a cleaning head located on the cleaning unit, which includes a plurality of recesses defined that overlap at least partially with the nozzles in a plan view, contains a hygroscopic substance, and moves in the first and second directions.

Description

[[Technical Field]]

[0001] The present invention relates to an inkjet printing apparatus and a cleaning method for an inkjet printing apparatus. [[Background Art]]

[0002] In general, organic light emitting diode displays (OLEDs), which are excellent in luminance characteristics and viewing angle characteristics and do not require a separate light source unit unlike liquid crystal display devices, have attracted attention as next-generation flat panel display devices. Organic light emitting display devices do not require a separate light source and can be manufactured to be lightweight and thin. Furthermore, organic light emitting display devices have characteristics such as low power consumption, high luminance, and high response speed.

[0003] An organic light emitting display device includes a plurality of light emitting elements each including an anode, an organic light emitting layer, and a cathode. Holes and electrons are respectively injected from the anode and the cathode into the organic light emitting layer to form excitons, and the light emitting element emits light as the excitons transition to the ground state.

[0004] When manufacturing a light emitting element, the organic light emitting layer is manufactured by an inkjet printing apparatus. An organic material (or ink) for forming the organic light emitting layer is ejected onto a substrate from the inkjet printing apparatus, whereby the organic light emitting layer can be formed.

[0005] When manufacturing an organic light emitting display device, a high-resolution precision patterning process is required. As the pixel size of a high-resolution organic light emitting display device becomes smaller, the inkjet printing apparatus must eject a smaller amount of ink. If the amount of ink ejected from the inkjet printing apparatus is not finely controlled, a defective organic light emitting layer is produced. There is a demand for the development of an inkjet printing apparatus capable of finely controlling the amount of ink jetted from inkjet nozzles. [[Summary of the Invention]] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide an inkjet printing apparatus that can reduce the defect rate of the organic light-emitting layer.

[0007] The object of the present invention is to provide a cleaning method for an inkjet printing apparatus that can reduce the defect rate of the organic light-emitting layer. [Means for solving the problem]

[0008] An inkjet printing apparatus according to one embodiment of the present invention may include a first stage, a second stage on which a substrate is disposed on and located above the first stage and includes a heater located inside, and on which a substrate is disposed including a print area that overlaps with the heater in a plan view, a housing located on the substrate, a plurality of print heads located inside the housing, a plurality of nozzles located on the lower surface of each of the print heads, and an ink supply device that supplies ink to the print heads, and a head unit that moves in a first direction, disposed above the first stage and moving in a second direction intersecting the first direction, and a cleaning head disposed above the cleaning unit and having a plurality of recesses defined that overlap at least a portion with the nozzles in a plan view, containing a hygroscopic substance, and moving in the first and second directions.

[0009] The nozzle may include a first nozzle group defined as a plurality of first nozzles arranged in the first direction, a second nozzle group defined as a plurality of second nozzles arranged in the first direction, and a third nozzle group defined as a plurality of third nozzles arranged in the first direction.

[0010] The first nozzle group, the second nozzle group, and the third nozzle group may be arranged in the second direction.

[0011] The first nozzle and the third nozzle may be arranged in the same row corresponding to the second direction.

[0012] The second nozzles may be arranged in rows between the rows in which the first nozzles are located.

[0013] In a plan view, the cleaning head may include a first cleaning head portion in which the first nozzle, the third nozzle, and the recess overlap.

[0014] In a plan view, the cleaning head may include a second cleaning head portion in which the second nozzle and the recess overlap.

[0015] In the inkjet printing apparatus, the second stage may further include adsorption pores.

[0016] The inkjet printing apparatus may further include a first frame connecting the first stage and the head unit.

[0017] The inkjet printing apparatus may further include a second frame positioned above the cleaning unit and connecting the cleaning unit and the cleaning head.

[0018] A cleaning method for an inkjet printing apparatus according to one embodiment of the present invention may include the steps of: placing a first stage and a second stage having a heater inside on the first stage; placing a substrate having a print area that overlaps with the heater on the second stage in a plan view; placing a head unit having a plurality of nozzles on the substrate; ejecting ink toward the substrate through the nozzles; placing a cleaning head adjacent to the lower surface of the nozzles; and absorbing the ink remaining on the nozzles through the cleaning head.

[0019] The head unit moves in a first direction, and the head unit further includes a housing, a plurality of print heads disposed inside the housing, and an ink supply device for supplying ink to the print heads, wherein the nozzles may be located on the underside of each of the print heads.

[0020] The step of positioning the cleaning head adjacent to the lower surface of the nozzle may include moving the cleaning head in the first direction, a second direction intersecting the first direction, and a third direction intersecting the plane defined by the first and second directions, to position the cleaning head adjacent to the lower surface of the nozzle.

[0021] The cleaning method for the inkjet printing apparatus may further include the step of positioning a cleaning unit, which moves the cleaning head in the first and second directions, below the cleaning head.

[0022] The cleaning head contains a hygroscopic substance, and the cleaning head may have a plurality of recesses that overlap with, at least in part, the nozzle.

[0023] The cleaning method for the inkjet printing apparatus may further include the step of bringing the cleaning head into contact with the ink remaining in the nozzle.

[0024] The nozzles include a first nozzle group defined as a plurality of first nozzles arranged in the first direction, a second nozzle group defined as a plurality of second nozzles arranged in the first direction, and a third nozzle group defined as a plurality of third nozzles arranged in the first direction, wherein the first nozzle group, the second nozzle group, and the third nozzle group may be arranged in the second direction.

[0025] The cleaning head may include: the first cleaning head portion disposed adjacent to lower surfaces of the first and third nozzles and configured to absorb ink remaining in the first and third nozzles; and the second cleaning head portion disposed adjacent to a lower surface of the second nozzle and configured to absorb ink remaining in the second nozzle.

Effects of the Invention

[0026] According to the above description, in the inkjet printing apparatus according to an embodiment of the present invention, the cleaning head is movable in a first direction. The cleaning head contains a hygroscopic material, and when the cleaning head vibrates in the first direction, residual ink remaining in the nozzles after the ink INK (see FIG. 5a) ejection process of the nozzles can be absorbed by the cleaning head. The cleaning head removes residual ink without directly contacting the nozzles, thereby reducing or eliminating damage to the nozzle ejection portions and clogging of the nozzle ejection portions caused by drying of residual ink. Furthermore, it can prevent damage to the water-repellent material coated on the nozzle ejection portions.

Brief Description of the Drawings

[0027] [Figure 1] It is a block diagram of an electronic device according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of an electronic device according to an embodiment of the present invention. [Figure 3] It is a diagram showing a method of forming an organic light-emitting layer using an inkjet printing apparatus. [Figure 4] It is a diagram exemplarily showing a cross-section of any one pixel shown in FIG. 3. [Figure 5a] It is a perspective view of an inkjet printing apparatus according to an embodiment of the present invention. [Figure 5b] It is a cross-sectional view showing a section taken along line I-I’ of FIG. 5a. [Figure 6] It is a schematic perspective view showing a head unit according to an embodiment of the present invention. [Figure 7a]This is a plan view of an inkjet printing apparatus according to one embodiment of the present invention. [Figure 7b] This is a plan view of an inkjet printing apparatus according to one embodiment of the present invention. [Figure 8a] This is a cross-sectional view of a head unit and cleaning unit according to one embodiment of the present invention. [Figure 8b] This is a cross-sectional view of a head unit and cleaning unit according to one embodiment of the present invention. [Figure 8c] This is a cross-sectional view of a head unit and cleaning unit according to one embodiment of the present invention. [Figure 9a] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Figure 9b] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Figure 9c] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Figure 9d] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Figure 9e] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Figure 9f] This is a schematic cross-sectional view showing a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0028] In this specification, when a component (or region, layer, part, etc.) is referred to as being "on top of," "connected to," or "joined" another component, it means that it can be directly placed on top of, connected to, or joined to the other component, or that a third component can be placed between them.

[0029] The same drawing symbol refers to the same component. Furthermore, in drawings, the thickness, proportions, and dimensions of components are exaggerated for the sake of effective explanation of the technical content. "and / or" includes all combinations of one or more components defined by the relevant component.

[0030] Terms such as "first," "second," etc., are used to describe a variety of components, but the components are not limited to those terms. The terms are used solely for the purpose of distinguishing one component, part, region, layer, or part from other components, parts, regions, layers, or parts. For example, without departing from the scope of the present invention, a first component, first part, first region, first layer, or first part may be named a second component, second part, second region, second layer, or second part, and similarly, a second component, second part, second region, second layer, or second part may be named a first component, first part, first region, first layer, or first part. A singular expression includes plural expressions unless the context clearly indicates otherwise.

[0031] Furthermore, terms such as "down," "on the lower side," "up," and "on the upper side" are used to describe the correlations between the components shown in the drawing. These terms are relative concepts and are described in relation to the direction shown in the drawing.

[0032] Terms such as "includes" or "has" indicate the presence of features, figures, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood not to pre-exist to exclude the presence or possibility of adding one or more other features, figures, steps, actions, components, parts, or combinations thereof.

[0033] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as those generally understood by those skilled in the art in the field to which the present invention pertains. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an overly idealistic or formal sense unless expressly defined herein.

[0034] Embodiments of the present invention will be described below with reference to the drawings.

[0035] Figure 1 is a block diagram of an electronic device according to one embodiment of the present invention.

[0036] Referring to Figure 1, an electronic device 10 according to one embodiment may include a display module 11, a processor 12, a memory 13, and a power supply module 14.

[0037] The processor 12 may include at least one of the following: a central processing unit (CPU), an application processor (AP), a graphics processing unit (GPU), a communication processor (CP), an image signal processor (ISP), and a controller.

[0038] Memory 13 can store data information necessary for the operation of the processor 12 and the display module 11. When the processor 12 executes an application stored in memory 13, video data signals and / or input control signals are transmitted to the display module 11, which can process the provided signals and output video information via the display screen.

[0039] The power module 14 may include a power supply module such as a power adapter or a battery device, and a power conversion module that converts the power supplied by the power supply module to generate the power necessary for the operation of the electronic device 10.

[0040] At least one of the components of the electronic device 10 described above may be included in the display device according to the embodiment described above. Furthermore, some of the individual modules functionally contained within a single module may be included in the display device, while others may be provided separately from the display device. For example, the display device includes a display module 11, while the processor 12, memory 13, and power supply module 14 may be provided in the form of other devices within the electronic device 10 rather than in the display device.

[0041] Figure 2 is a schematic diagram of an electronic device according to one embodiment of the present invention.

[0042] Referring to Figure 2, the various electronic devices to which the display device according to the embodiment is applied include not only image display electronic devices such as smartphones 10_1a, tablet PCs 10_1b, laptops 10_1c, televisions 10_1d, and desk monitors 10_1e, but also wearable electronic devices including display modules such as smart glasses 10_2a, head-mounted displays 10_2b, and smartwatches 10_2c, and vehicle electronic devices 10_3 including display modules such as CIDs (Center Information Displays) and rearview mirror displays located on the instrument panel, center fascia, and dashboard of an automobile.

[0043] The electronic device may include a display device that displays images and a processor that processes image signals and provides them to the display device. The display device may include pixels manufactured by a cleaning method for an inkjet printing apparatus, which will be described later.

[0044] Figure 3 shows a method for forming an organic light-emitting layer using an inkjet printing apparatus. Figure 4 is an illustrative diagram showing a cross-section of one of the pixels shown in Figure 3.

[0045] For the sake of explanation, Figure 3 shows an illustrative cross-section of the nozzle NZ portion where three nozzle holes NH are defined.

[0046] Referring to Figures 3 and 4, an inkjet printing apparatus IPA (see Figure 5a) may be used to form the light-emitting layer EML. A pixel PX may include a transistor TR and a light-emitting element OLED connected to the transistor TR. Although one pixel PX is shown exemplarily, substantially multiple pixels PX may be arranged on the base layer BS.

[0047] A light-emitting element (OLED) may include a first electrode AE, a second electrode CE, and a light-emitting layer EML. The first electrode AE ​​may be the anode electrode, and the second electrode CE may be the cathode electrode.

[0048] The transistor TR and the light-emitting element OLED may be placed on the base layer BS. The planar region of the base layer BS may be divided into a light-emitting area PA and a non-light-emitting area NPA surrounding the light-emitting area PA. The light-emitting element OLED may be placed on top of the light-emitting area PA.

[0049] A buffer layer BFL is placed on top of the base layer BS, and the buffer layer BFL may be an inorganic layer.

[0050] Semiconductor patterns S, A, and D may be arranged on the buffer layer BFL. The semiconductor patterns S, A, and D may contain polysilicon, but are not limited to this; the semiconductor patterns S, A, and D may also contain amorphous silicon or metal oxides.

[0051] The semiconductor patterns S, A, and D can be doped with an N-type dopant or a P-type dopant. The semiconductor patterns S, A, and D may include high-doping and low-doping regions. The conductivity of the high-doping region is greater than that of the low-doping region and can substantially function as the source and drain electrodes of a transistor TR. The low-doping region can substantially correspond to the active (or channel) of the transistor.

[0052] The source S, active A, and drain D of the transistor TR may consist of semiconductor patterns S, A, and D. A first insulating layer INS1 may be placed on the semiconductor patterns S, A, and D. The gate electrode G of the transistor TR may be placed on the first insulating layer INS1. A second insulating layer INS2 may be placed on the gate electrode G. A third insulating layer INS3 may be placed on the second insulating layer INS2.

[0053] The connecting electrode CNE can be positioned between the transistor TR and the light-emitting element OLED to connect the transistor TR and the light-emitting element OLED. The connecting electrode CNE may include a first connecting electrode CNE1 and a second connecting electrode CNE2.

[0054] The first connecting electrode CNE1 is placed on the third insulating layer INS3 and may be connected to the drain D via the first contact hole CH1 defined in the first to third insulating layers INS1 to INS3. The fourth insulating layer INS4 may be placed on the first connecting electrode CNE1. The fifth insulating layer INS5 may be placed on the fourth insulating layer INS4.

[0055] A second connecting electrode CNE1 may be placed on a fifth insulating layer INS5. A second connecting electrode CNE2 may be connected to a first connecting electrode CNE1 via a second contact hole CH2 defined in the fifth insulating layer INS5. A sixth insulating layer INS6 may be placed on top of the second connecting electrode CNE2. The first insulating layer INS1 to the sixth insulating layer INS6 may be inorganic or organic layers.

[0056] A first electrode AE ​​may be placed on a sixth insulating layer INS6. The first electrode AE ​​may be connected to a second connecting electrode CNE2 via a third contact hole CH3 defined in the sixth insulating layer INS6. A pixel definition film PDL may be placed on the first electrode AE ​​and the sixth insulating layer INS6 to expose a predetermined portion of the first electrode AE. A pixel opening PX_OP may be defined in the pixel definition film PDL to expose a predetermined portion of the first electrode AE.

[0057] The light-emitting layer (EML) may be positioned above the first electrode (AE). The EML may be positioned in the region corresponding to the pixel aperture (PX_OP). The EML may contain organic and / or inorganic materials. The EML may generate one of the following light colors: red, green, and blue.

[0058] The second electrode CE is positioned on top of the light-emitting layer EML. The second electrode CE may be commonly positioned in pixels PX.

[0059] A thin-film encapsulation layer (TFE) may be placed on top of a light-emitting element (OLED). The TFE may be placed on top of a second electrode (CE) to cover a pixel (PX). The TFE may include at least two inorganic layers and an organic layer between the inorganic layers. The inorganic layers may protect the pixel (PX) from moisture / oxygen. The organic layer may protect the pixel (PX) from foreign matter such as dust particles.

[0060] A first voltage can be applied to the first electrode AE ​​via a transistor TR, and a second voltage having a lower level than the first voltage can be applied to the second electrode CE. Holes injected into the light-emitting layer EML combine with electrons to form excitons, and the light-emitting element OLED can emit light as the excitons transition to the ground state.

[0061] Figure 5a is a perspective view of an inkjet printing apparatus according to one embodiment of the present invention. Figure 5b is a cross-sectional view showing the section obtained by cutting along line I-I' in Figure 5a.

[0062] Referring to Figures 5a and 5b, the inkjet printing apparatus IPD may include a first stage STG1, a second stage STG2, a head unit HU, a cleaning unit CLU, and a cleaning head CLH.

[0063] The second stage STG2 may include a heater HTR and a circuit board SUB. The second stage STG2 may be placed on top of the first stage STG1. The heater HTR may be placed inside the second stage STG2.

[0064] The heater HTR can dry the ink (see Figure 3) by applying heat to it. In other words, once the ink is applied to the print area TPA, the heater HTR can dry the ink.

[0065] The second stage STG2 may have adsorption holes (not shown). A substrate SUB may be adsorbed and fixed onto the second stage STG2 through the adsorption holes of the second stage STG2. In plan view, the substrate SUB may include a printed area TRP that overlaps with a heater HTR.

[0066] The circuit board SUB may move in the second direction DR2 during the second stage STG2. When the circuit board SUB moves in the second direction, the head unit HU appears to move in the second direction DR2 on the second stage STG2.

[0067] The head unit HU can discharge ink onto the substrate SUB. The ink discharged from the head unit HU can be cured to form the light-emitting layer EML (see Figure 4). The details of the head unit HU will be described later.

[0068] An inkjet printing apparatus IPD may include a cleaning unit CLU positioned above a first stage STG1 and moving in a second direction DR2. The cleaning unit CLU may clean the nozzles NZ of the printhead PHD as it moves in the second direction DR2. A head unit HU may be positioned above the cleaning unit CLU, and the cleaning unit CLU may move in the second direction DR2, while the head unit HU moves in the first direction DR1, respectively, to clean the nozzles NZ.

[0069] The cleaning head CLH may be positioned on top of the cleaning unit CLU. In a plan view, the cleaning head CLH may be defined by a plurality of recesses RCS that overlap at least partially with the nozzle NZ. The recesses RCS may contain a hygroscopic material.

[0070] The inkjet printing apparatus IPD may further include a first frame FR1 connecting a head unit HU on a first stage STG1. The inkjet printing apparatus IPD may further include a second frame FR2 connecting a cleaning unit CLU and a cleaning head CLH. The second frame FR2 may be positioned on top of the cleaning unit CLU. Through the second frame FR2, the cleaning head CLH may move in a first direction DR1, a second direction DR2, and a third direction DR3.

[0071] Figure 6 is a schematic perspective view showing a head unit according to one embodiment of the present invention. Figures 7a and 7b are plan views of an inkjet printing apparatus according to one embodiment of the present invention.

[0072] For the sake of clarity, the first frame FR1 and the second frame FR2 are omitted in Figures 7a and 7b.

[0073] Referring to Figures 6, 7a, and 7b, the head unit HU may include a housing HOU positioned on a substrate SUB, a plurality of print heads PHD positioned inside the housing HOU, a plurality of nozzles NZ1, NZ2, NZ3, and an ink supply unit ISU. The head unit HU may move in a first direction DR1.

[0074] Nozzles NZ1, NZ2, and NZ3 may be positioned on the underside of each printhead PHD. Nozzles NZ1, NZ2, and NZ3 may include a plurality of first nozzles NZ1 arranged in the first direction DR1. The first nozzles NZ1 may be defined as the first nozzle group NZ1G. Nozzles NZ1, NZ2, and NZ3 may include a plurality of second nozzles NZ2 arranged in the first direction DR1. The second nozzles NZ2 may be defined as the second nozzle group NZ2G. Nozzles NZ1, NZ2, and NZ3 may include a plurality of third nozzles NZ3 arranged in the first direction DR1. The third nozzles NZ3 may be defined as the third nozzle group NZ3G.

[0075] The first nozzle group NZ1G, the second nozzle group NZ2G, and the third nozzle group NZ3G can be arranged in the second direction DR1 intersecting the first direction DR1. In other words, the first nozzle group NZ1G, the second nozzle group NZ2G, and the third nozzle group NZ3G can be connected to the ink supply device ISU and grouped together. Figures 6 and 7 show exemplary nozzles NZ1, NZ2, and NZ3 of the first nozzle group NZ1G, the second nozzle group NZ2G, and the third nozzle group NZ3G, respectively, but the number of nozzles NZ1, NZ2, and NZ3 is not limited to these, as long as the nozzles NZ1, NZ2, and NZ3 can form groups.

[0076] The first nozzle NZ1 and the third nozzle NZ3 may be arranged in the same corresponding column in the second direction DR2. The first nozzle NZ1 and the third nozzle NZ3 may overlap in the second direction DR2. The second nozzle NZ2 may be positioned in a column between the columns in which the first nozzle NZ1 is positioned. In other words, the second nozzle NZ2 does not have to overlap with the first nozzle NZ1 and the third nozzle NZ3 in the second direction DR2. From the perspective of the second direction DR2, the second nozzle NZ2 may be positioned between the first nozzle NZ1 and the third nozzle NZ3.

[0077] The ink supply unit (ISU) may be connected to the print head (PHD). The ink supply unit (ISU) may supply ink (see Figure 2) to the print head (PHD). Ink may be discharged from nozzles NZ1, NZ2, and NZ3 via the ink supply unit (ISU).

[0078] The cleaning head CLH may include a first cleaning portion CLHP1 and a second cleaning portion CLHP2.

[0079] The first cleaning head portion CLHP1 may be a position where the cleaning head CLH overlaps the first nozzle NZ1 and the third nozzle NZ3 with the recess RCS in a plan view. In the first cleaning head portion CLHP1, the cleaning head CLH can move in the first direction DR1 and the second direction DR2 to clean the first nozzle NZ1 and the third nozzle NZ3.

[0080] The second cleaning head portion CLHP2 may be a position where the cleaning head CLH overlaps the second nozzle NZ2 and the recess RCS in a plan view. In the second cleaning head portion CLHP2, the cleaning head CLH can move in the first direction DR1 and the second direction DR2 to clean the second nozzle NZ2.

[0081] Figures 8a to 8c are cross-sectional views of a head unit and cleaning unit according to one embodiment of the present invention. For convenience of explanation, only the housing HOU, print head PHD, and nozzle NZ are shown in the head unit HU.

[0082] Referring to Figures 8a to 8c, the cleaning head CLH may move in the first direction DR1. The nozzle NZ may be located inside the print head PHD. The bottom surface of the print head PHD in the third direction DR3 and the bottom surface of the nozzle NZ in the third direction DR3 may be the same plane. The cleaning head CLH contains a hygroscopic material, and when the cleaning head CLH vibrates in the first direction DR1, residual ink remaining in the nozzle NZ after the ink ejection process (see Figure 5a) can be absorbed by the cleaning head CLH. The cleaning head CLH removes residual ink without direct contact with the nozzle NZ, reducing or eliminating damage to the nozzle ejection part and clogging of the nozzle ejection part due to drying of residual ink. It can also prevent damage to the water-repellent material coated on the nozzle ejection part of the nozzle NZ.

[0083] Figures 9a to 9g are schematic cross-sectional views illustrating a cleaning method for an inkjet printing apparatus according to one embodiment of the present invention.

[0084] For the sake of explanation, in Figures 9d and 9f, components other than the print head PHD, housing HOU, and nozzle NZ are omitted in the head unit HU.

[0085] Referring to Figure 9a, the cleaning method for an inkjet printing apparatus may include the step of preparing the first stage STG1.

[0086] Referring to Figure 9b, a cleaning method for an inkjet printing apparatus may include the step of placing a second stage STG2 on top of a first stage STG1. The second stage STG2 may include a heater HTR inside.

[0087] Referring to Figure 9c, a cleaning method for an inkjet printing apparatus may include, in plan view, the step of placing a substrate SUB containing a print area TPA superimposed on a heater HTR on a second stage STG2.

[0088] Referring to Figure 9d, a cleaning method for an inkjet printing apparatus may include a step of positioning a head unit HD (see Figure 5a) that moves in a first direction DR1, comprising a housing HOU placed on a substrate SUB, a plurality of print heads PHD placed inside the housing HOU, a plurality of nozzles NZ placed on the underside of each print head PHD, and an ink supply unit ISU (see Figure 5a) that supplies ink (see Figure 5a) to the print heads PHD. A cleaning method for an inkjet printing apparatus may include a step of ejecting ink (see Figure 5a) toward the substrate SUB via the nozzles NZ.

[0089] Referring to Figure 9e, a cleaning method for an inkjet printing apparatus may include the step of positioning a cleaning unit CLU on a first stage STG1, moving in a second direction DR2 intersecting a first direction DR1. In a plan view, a cleaning head CLH containing a hygroscopic material may be positioned on the cleaning unit CLU, where a plurality of recesses RCS are defined, at least partially overlapping with the nozzle NZ.

[0090] Referring to Figure 9f, the head unit HU may move in a first direction DR1. A cleaning method for an inkjet printing apparatus may include the step of moving the cleaning unit CLU in a first direction DR1 so as to overlap the head unit HU in a plan view. A cleaning method for an inkjet printing apparatus may include the step of moving the cleaning unit CLU in a second direction DR2 so as to overlap the head unit HU in a plan view.

[0091] A cleaning method for an inkjet printing apparatus may include the step of moving a cleaning head CLH in a third direction DR3 that intersects both a first direction DR1 and a second direction DR2. The cleaning head CLH may be moved in the third direction DR3 by a second frame FR2 (see Figure 5a). The cleaning head CLH may be positioned so that the recess RCS overlaps with the nozzle NZ when it moves in the third direction DR3.

[0092] Referring to Figures 7b and 9f, the cleaning head CLH may include a first cleaning head portion CLHP1 positioned adjacent to the lower surfaces of the first nozzle NZ1 and the third nozzle NZ3 in a plan view, which absorbs ink remaining in the first nozzle NZ1 and the third nozzle NZ3 (see Figure 5a). The cleaning head CLH may also include a second cleaning head portion CLHP2 positioned adjacent to the lower surface of the second nozzle NZ2 in a plan view, which absorbs ink remaining in the second nozzle NZ2 (see Figure 5a).

[0093] Referring to Figure 9f, a cleaning method for an inkjet printing apparatus may include the step of positioning the upper surface of the cleaning head CLH on the lower surface of the print head PHD. A cleaning method for an inkjet printing apparatus may include the step of positioning the cleaning head CLH adjacent to the lower surface of the nozzle NZ. A cleaning method for an inkjet printing apparatus may include the step of absorbing the ink remaining on the nozzle NZ (see Figure 5a) via the cleaning head CLH. A cleaning method for an inkjet printing apparatus may further include the step of bringing the cleaning head CLH into contact with the ink remaining on the nozzle.

[0094] The cleaning head CLH may move in a third direction DR3 and be positioned to contact the head unit HU. This movement may cause the cleaning head CLH to begin removing residual ink (see Figure 5a) present in the ejection section of the nozzle NZ.

[0095] Although preferred embodiments of the present invention have been described so far with reference, a person skilled in the art or with ordinary knowledge in the art will understand that the present invention can be modified and altered in various ways without departing from the spirit and art domain of the invention as described in the claims below.

[0096] Therefore, the technical scope of the present invention is not limited to what is described in the detailed description of the specification, but should be determined by the claims. [Explanation of symbols]

[0097] STG1: Stage 1, STG2: Stage 2, HTR: Heater, TPA: Print Area, SUB: Circuit Board, HOU: Enclosure, PHD: Print Head, NZ: Nozzle, INK: Ink, ISU: Ink Supply Unit, HU: Head Unit, NZ1: Nozzle 1, NZ2: Nozzle 2, NZ3: Nozzle 3, CLU: Cleaning Unit, RCS: Recess, CLH: Cleaning Head

Claims

1. Stage 1 and A second stage is arranged on which a substrate is placed, which includes a heater located inside the first stage and a printed area that overlaps with the heater in a plan view. A head unit that moves in a first direction includes a housing disposed on the substrate, a plurality of print heads disposed inside the housing, a plurality of nozzles disposed on the lower surface of each of the print heads, and an ink supply device that supplies ink to the print heads. A cleaning unit positioned on the first stage and moving in a second direction intersecting the first direction, A cleaning head is provided, which is positioned on the cleaning unit and has a plurality of recesses defined such that at least a portion of it overlaps with the nozzle in a plan view, contains a hygroscopic substance, and moves in the first and second directions, Inkjet printing equipment, including [specific feature / feature].

2. The aforementioned nozzle is A first nozzle group is defined as a plurality of first nozzles arranged in the first direction, A second nozzle group is defined as a plurality of second nozzles arranged in the first direction, The inkjet printing apparatus according to claim 1, comprising a plurality of third nozzles defined as a third nozzle group and arranged in the first direction.

3. The inkjet printing apparatus according to claim 2, wherein the first nozzle group, the second nozzle group, and the third nozzle group are arranged in the second direction.

4. The inkjet printing apparatus according to claim 2, wherein the first nozzle and the third nozzle are arranged in the same corresponding row in the second direction.

5. The inkjet printing apparatus according to claim 4, wherein the second nozzle is arranged in a row between the rows in which the first nozzle is arranged.

6. In a plan view, the cleaning head includes a first cleaning head portion in which the first nozzle, the third nozzle and the recess overlap, as described in claim 2 of the inkjet printing apparatus.

7. In a plan view, the cleaning head includes a second cleaning head portion in which the second nozzle and the recess overlap, as described in claim 2 of the inkjet printing apparatus.

8. The inkjet printing apparatus according to claim 1, wherein the second stage further comprises adsorption pores.

9. The inkjet printing apparatus according to claim 1, further comprising a first frame connecting the first stage and the head unit.

10. The inkjet printing apparatus according to claim 1, further comprising a second frame disposed on the cleaning unit and connecting the cleaning unit and the cleaning head.

11. The steps include placing a first stage and a second stage containing a heater inside on top of the first stage, In a plan view, the steps include placing a substrate including a printed area that overlaps with the heater on the second stage, The steps include: arranging a head unit including multiple nozzles on the aforementioned substrate; The steps include: ejecting ink toward the substrate through the nozzle; The steps include: positioning the cleaning head adjacent to the lower surface of the nozzle, The steps include: absorbing the ink remaining in the nozzle via the cleaning head; A cleaning method for an inkjet printing device, including [details omitted].

12. The head unit moves in the first direction, The head unit is The casing and Multiple print heads are arranged inside the aforementioned enclosure, The present invention further includes an ink supply device that supplies the aforementioned ink to the print head, The cleaning method for an inkjet printing apparatus according to claim 11, wherein the nozzles are arranged on the lower surface of each of the print heads.

13. The step of positioning the cleaning head adjacent to the lower surface of the nozzle is: A cleaning method for an inkjet printing apparatus according to claim 11, comprising the step of moving the cleaning head in the first direction, the second direction intersecting the first direction, and the third direction intersecting the plane defined by the first and second directions, so that the cleaning head is positioned adjacent to the lower surface of the nozzle.

14. A cleaning method for an inkjet printing apparatus according to claim 13, further comprising the step of positioning a cleaning unit for moving the cleaning head in the first and second directions below the cleaning head.

15. The cleaning method for an inkjet printing apparatus according to claim 13, wherein the cleaning head contains a hygroscopic substance, and the cleaning head is defined with a plurality of recesses that overlap with, at least a portion of, the nozzle.

16. A cleaning method for an inkjet printing apparatus according to claim 15, further comprising the step of bringing the cleaning head into contact with the ink remaining in the nozzle.

17. The aforementioned nozzle is A first nozzle group is defined as a plurality of first nozzles arranged in the first direction, A second nozzle group is defined as a plurality of second nozzles arranged in the first direction, A third nozzle group is defined and includes a plurality of third nozzles arranged in the first direction, The cleaning method for an inkjet printing apparatus according to claim 11, wherein the first nozzle group, the second nozzle group, and the third nozzle group are arranged in the second direction.

18. The cleaning head is, A first cleaning head portion is positioned adjacent to the lower surfaces of the first and third nozzles and absorbs ink remaining in the first and third nozzles, A cleaning method for an inkjet printing apparatus according to claim 17, comprising: a second cleaning head portion positioned adjacent to the lower surface of the second nozzle and absorbing ink remaining in the second nozzle.

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