Control method of printing device, printing method, and inkjet device

Abstract

This invention provides a control method for a printing apparatus, a printing method, and an inkjet apparatus. The printing method for the substrate includes: an illumination mark imaging step, wherein an imaging component is positioned below a vision section of a printhead unit, and with the illumination device in the vision section turned on, the imaging component images the vision section to obtain an image containing an illumination mark; a printhead imaging step, wherein the imaging component is positioned below a printhead of the printhead unit, and an image of the lower part of the printhead is obtained; and an offset calculation step, wherein the distance between the printhead and the vision section is measured, and an offset is calculated based on the measured distance.

Description

Cross-reference to related applications

[0001] This application claims priority to Korean Patent Application No. 10-2024-0195184, filed on December 24, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a control method for a printing apparatus, a printing method, and an inkjet apparatus. Background Technology

[0003] In manufacturing displays, it is crucial to precisely apply ink to substrates such as glass. With the increasing performance of displays manufactured in recent years, even greater demands have been placed on the technology to apply precise amounts of ink to accurate locations on the substrate.

[0004] Inkjet printing technology, which uses an inkjet device to spray ink in the form of droplets onto a substrate, has the advantage of being able to attach ink droplets with high precision, and therefore can be widely used in display manufacturing processes.

[0005] An inkjet device has a printhead unit, which has nozzles that eject ink droplets. A substrate passes beneath the printhead unit, and the printhead unit ejects ink droplets onto the substrate passing through this area. To ensure that the printhead unit ejects ink droplets onto the desired area of ​​the substrate, the position of the printhead unit must be controlled. Only by precisely controlling the relative position of the printhead unit and the substrate can the ink droplets ejected by the printhead unit adhere to the accurate location on the substrate.

[0006] However, as the number of substrates processed by the inkjet printer increases, the position of the printhead unit, more specifically, the position of the printhead within the printhead unit, may shift. For example, the printhead position may shift due to various reasons such as degradation, wear, or loosening of fasteners caused by mechanical vibration. Therefore, in order to accurately attach ink droplets to the substrate, it is necessary to consider the situation of printhead position shift as described above and control the relative position of the substrate and the printhead unit. Summary of the Invention

[0007] (a) Technical problems to be solved The purpose of this invention is to provide a control method, a printing method, and an inkjet device for a printing apparatus capable of effectively performing printing steps on a substrate.

[0008] In addition, the present invention aims to provide a control method for a printing apparatus, a printing method, and an inkjet apparatus, which can accurately control the relative position of the printhead unit and the substrate even if the position of the printhead unit and / or the printhead provided by the printhead unit is offset.

[0009] In addition, the present invention aims to provide a control method for a printing apparatus, a printing method, and an inkjet apparatus, which can accurately control the relative position of the printhead unit and the substrate even if the position of the vision section of the printhead unit is shifted.

[0010] In addition, the present invention aims to provide a control method for a printing apparatus, a printing method, and an inkjet apparatus, which can accurately control the relative position of the printhead unit and the substrate even if part of the printhead unit is contaminated during the printing process.

[0011] The purpose of this invention is not limited thereto, and those skilled in the art will clearly understand other purposes not mentioned from the following description.

[0012] (II) Technical Solution This invention provides a method for printing on a substrate. The method may include: an illumination mark imaging step, wherein an imaging component is positioned below a vision section of a printhead unit, and with the illumination device in the vision section turned on, the imaging component images the vision section to obtain an image containing illumination marks; a printhead imaging step, wherein the imaging component is positioned below a printhead of the printhead unit, and an image of the lower part of the printhead is obtained; and an offset calculation step, wherein the distance between the printhead and the vision section is measured, and an offset is calculated based on the measured distance.

[0013] In addition, the present invention provides a control method for a printing apparatus. In this control method, the printing apparatus may include a printing table for performing a printing step on a substrate, a transport unit for transporting the substrate along the printing table, a printhead unit for ejecting ink droplets onto the substrate transported by the transport unit, and an imaging unit for photographing the printhead unit. The printhead unit includes a printhead having a nozzle for ejecting the ink droplets and a vision section disposed separately from the printhead and including an illumination device. The control method includes, with the illumination device of the vision section turned on, the imaging unit photographing the printhead and the vision section to measure the distance between the printhead and the vision section.

[0014] Additionally, the present invention provides an inkjet apparatus, which may include: a printing section for performing a printing step on a substrate; a maintenance section disposed side-by-side with respect to the printing section along a first direction; a gantry disposed to extend along the first direction when viewed from above and pass through the printing section and the maintenance section; a printhead unit disposed on the gantry and movably configured along the first direction for ejecting ink droplets onto the substrate; an imaging unit disposed in the maintenance section for imaging the printhead unit; and a controller, wherein the printing section includes: a printing table for ejecting gas onto the lower surface of the substrate to suspend the substrate; and a transport unit for moving the suspended substrate in a second direction perpendicular to the first direction, and the printhead unit... The unit includes: a housing; a plurality of printheads disposed in the housing; and a vision unit disposed in the housing. The controller is configured to control the imaging unit to capture images of the vision unit while the illumination device of the vision unit is turned on, and to move the imaging unit to capture images of the lower part of the printheads; to measure the distance between the vision unit and the printheads based on the captured images; to calculate the difference between the measured distance and the reference distance by comparing the measured distance with a pre-stored reference distance, i.e., to calculate an offset; and to control the printhead unit to adjust the position of the printheads ejecting ink droplets onto the substrate based on the calculated offset, i.e., to adjust the printing position.

[0015] (III) Beneficial Effects According to one embodiment of the present invention, the printing step on the substrate can be performed efficiently.

[0016] Furthermore, according to one embodiment of the present invention, even if the position of the nozzle unit and / or the nozzles provided by the nozzle unit is offset, the relative position of the nozzle unit and the substrate can be precisely controlled.

[0017] Furthermore, according to one embodiment of the present invention, even if the position of the vision portion of the nozzle unit is shifted, the relative position of the nozzle unit and the substrate can be precisely controlled.

[0018] Furthermore, according to one embodiment of the present invention, even if a portion of the printhead unit becomes contaminated during the printing process, the relative position of the printhead unit and the substrate can be precisely controlled.

[0019] The effects of the present invention are not limited to those described above. For any effects not mentioned, those skilled in the art will clearly understand them through this specification and the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a diagram of a printing apparatus according to an embodiment of the present invention, viewed from above.

[0021] Figure 2 Viewed from below Figure 1 A diagram of the nozzle plate of the nozzle.

[0022] Figure 3 and Figure 4 This diagram illustrates the state of the printing apparatus of the present invention performing the printing step on the substrate.

[0023] Figure 5 This is a flowchart illustrating a printing method according to an embodiment of the present invention.

[0024] Figure 6 Is to show execution Figure 5 A diagram of the shooting unit for the lighting marker shooting steps.

[0025] Figure 7 It is a symbol indicating passage. Figure 6 The image obtained by the camera unit.

[0026] Figure 8 Is to show execution Figure 5 The image shows the shooting unit of the nozzle shooting process.

[0027] Figure 9 It is used to explain in Figure 5 The diagram shows the method for calculating the offset in the offset calculation steps.

[0028] Figure 10 Is to show execution Figure 5 A diagram showing the state of the nozzle unit during the alignment and marking process.

[0029] Figures 11a to 11d This is a diagram illustrating the offset calculation steps included in a printing method according to another embodiment of the present invention.

[0030] Figure 12 This is a diagram illustrating the printing steps included in a printing method according to another embodiment of the present invention.

[0031] Figure 13 This is a diagram of a printing apparatus according to another embodiment of the present invention, viewed from above.

[0032] Figure 14 This is a diagram of a printing apparatus according to another embodiment of the present invention, viewed from above.

[0033] Explanation of reference numerals in the attached figures G: Substrate; 1: Printing apparatus; 10: Printing Department; 11: Printing Table; 12: Conveyor clamps; 20: Maintenance unit; 21: Maintenance console; 30: Gantry; 40: Nozzle unit; 41: Housing; 42: Nozzle; NP: Nozzle plate; N: Nozzle; 43: Vision unit; 50: Shooting unit; 51: Moving plate; 52: Camera component; 60: Controller; S1: Illumination mark shooting procedure; S2: Nozzle shooting procedure; S3: Offset calculation step; S4: Alignment mark shooting step; S5: Printing steps. Detailed Implementation

[0034] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Furthermore, in describing preferred embodiments of the invention in detail, detailed descriptions of relevant well-known functions or structures are omitted if it is deemed unnecessary to obscure the spirit of the invention. Additionally, the same reference numerals are used in all the drawings for parts with similar functions and effects.

[0035] When describing the inclusion of other components, unless specifically stated otherwise, other components are not excluded and may be further included. Specifically, the terms "comprising" or "having" in the specification are used to specify the presence of the described features, numbers, steps, actions, components, parts, or combinations thereof, without pre-excluding the presence or additional possibilities of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0036] Unless explicitly stated in the context, singular expressions include plural forms. Furthermore, for greater clarity, the shapes and dimensions of elements in the accompanying drawings may be enlarged.

[0037] Terms such as "first" and "second" can be used to describe various constituent elements, but these constituent elements should not be limited by these terms. These terms are used to distinguish one constituent element from another. For example, without departing from the scope of the invention, a first constituent element may be named a second constituent element, and similarly, a second constituent element may be named a first constituent element.

[0038] When describing a component as "connected" or "linked" to other components, it should be understood as being directly connected or linked to those other components, although other components may exist in between. Conversely, when describing a component as "directly connected" or "directly linked" to other components, it should be understood as meaning that no other components exist in between. Other expressions used to describe the relationship between components, such as "between ~" and "directly ~ between", or "~ adjacent" and "~ directly adjacent", should also be interpreted similarly.

[0039] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries shall be interpreted as having the same meaning as those in the relevant technical documents, and shall not be construed as having an idealized or overly formal meaning unless expressly defined in this application.

[0040] Figure 1 This is a top view of a printing apparatus according to an embodiment of the present invention. (Refer to...) Figure 1 According to one embodiment of the present invention, the printing apparatus 1 can jet ink droplets onto a substrate G to form an ink film on the substrate G. The printing apparatus 1 can be an inkjet device. The substrate G can be a glass substrate.

[0041] The printing apparatus 1 may include a printing unit 10, a maintenance unit 20, a gantry 30, a printhead unit 40, a shooting unit 50, and a controller 60.

[0042] The printing section 10 can be the area where printing is performed on the substrate G. The printing section 10 may include a printing table 11 and a transport fixture 12 (an example of a transport unit). The substrate G can be loaded and / or unloaded on the printing table 11. The printing table 11 can spray air onto the lower surface of the substrate G, causing the substrate G to float. When the lower surface of the substrate G is in direct contact with the printing table 11, impurities such as particles may be generated due to the contact. These impurities may adhere to the upper surface of the substrate G, resulting in a decrease in the quality of the manufactured display panel. To solve this problem, the printing table 11 sprays air onto the lower surface of the substrate G, thus separating the lower surface of the substrate G from the printing table 11.

[0043] The suspended substrate G can be held by the transport clamp 12. The transport clamp 12 can hold one side of the substrate G (or both sides if needed). The transport clamp 12 can hold the lower part of the edge region of the substrate G by vacuum adsorption. The transport clamp 12 can be configured to move along the second direction Y. The transport clamp 12 can hold one side of the suspended substrate G and move the substrate G along the second direction Y while moving along the second direction Y.

[0044] In the above example, although the illustration uses the example of the printing table 11 spraying gas (Air) onto the lower surface of the substrate G to suspend the substrate G, it is not limited to this. For example, the printing table 11 may include a substrate moving plate and a moving mechanism, the substrate moving plate being capable of moving the substrate G in the front-back direction, and the moving mechanism including a motor, guide rails, and guide blocks capable of moving the substrate moving plate. The substrate moving plate and the moving mechanism (another example of a transport unit) may be configured to move the substrate G in the second direction Y. In addition, the upper surface of the substrate moving plate may be a placement surface for placing the entire lower surface of the substrate G.

[0045] Below, the transport direction of substrate G can be defined as the second direction Y, the direction perpendicular to the second direction Y when viewed from above can be defined as the first direction X, and the direction perpendicular to the first direction X and the second direction Y can be defined as the third direction Z. The third direction Z can represent the direction perpendicular to the ground.

[0046] The maintenance unit 20 may include a maintenance table 21 having the same or similar shape and function as the printing table 11 described above. The maintenance unit 20 may be arranged side-by-side with respect to the printing unit 10 along the first direction X. In the maintenance unit 20, maintenance operations such as inspection, test spraying, cleaning spraying, cleaning, replacement, and repair can be performed on the printhead unit 40, which will be described later. Furthermore, in the maintenance unit 20, the imaging unit 50, described later, can capture images of the vision section 43 and the reference nozzle RN to calculate the distances OX and OY between the vision section 43 and the reference nozzle RN of the printhead unit 40.

[0047] The maintenance unit 20 can have a similar structure and environment to the printing unit 10. For example, the printing unit 10 and the maintenance unit 20 can be located in the same sealed chamber. The sealed chamber can contain an inert gas such as nitrogen. That is, both the printing unit 10 and the maintenance unit 20 can be controlled in an inert gas atmosphere. As described above, the printing unit 10 and the maintenance unit 20 are controlled in the same or similar process environment because operations such as test spraying to test the performance of the printhead unit 40 are performed in the maintenance unit 20.

[0048] The gantry 30 may have a vertical extension extending in a vertical direction and a horizontal extension extending in a horizontal direction. The vertical extension may be located on the side of the printing table 11 of the printing unit 10 and the side of the maintenance table 21 of the maintenance unit 20, respectively. Furthermore, the horizontal extension may be located above the printing table 11 and the maintenance unit 20. The horizontal extension may extend in a first direction X.

[0049] Furthermore, the gantry 30 may include a moving mechanism capable of moving the printhead unit 40. For example, the moving mechanism in the gantry 30 may consist of a motor, a guide rail, and a moving bracket that moves along the guide rail. The printhead unit 40 can move along the first direction X via this moving mechanism. The printhead unit 40 can move between the printing section 10 and the maintenance section 20 via the gantry 30.

[0050] When the printhead unit 40 is located above the printing section 10, the printing process can be performed on the substrate G. When the printhead unit 40 is located above the maintenance section 20, maintenance operations such as inspection, test spraying, cleaning spraying, cleaning, replacement, and repair can be performed on the printhead unit 40.

[0051] The printhead unit 40 can eject ink droplets onto the substrate G. The printhead unit 40 can eject ink droplets onto the substrate G to form an ink film on the substrate G. The printhead unit 40 may include a housing 41, a plurality of printheads 42, and a vision unit 43.

[0052] The housing 41 can be combined with the moving mechanism in the gantry 30. The housing 41 can be a main component for inserting and fixing the nozzles 42. Multiple nozzles 42 can be inserted and fixed into the housing 41. Figure 2 As shown, each of the multiple printheads 42 may have a nozzle plate NP. Multiple nozzles N are formed in each nozzle plate NP. Each nozzle N can eject ink droplets. Although Figure 2 The example shows 24 nozzles N formed in each nozzle plate NP, but it is not limited to this. For example, the number of nozzles N formed in each nozzle plate NP can be tens to thousands, and varies greatly.

[0053] In addition, among the multiple nozzles N formed in the nozzle plate NP, the nozzle N closest to the corner of the nozzle plate NP can be used as the reference nozzle RN for calculating the spacing OX and OY as described later.

[0054] Refer again Figure 1 The vision unit 43 can be disposed on the side of the housing 41. The vision unit 43 can be a camera including an illumination device. The vision unit 43 is capable of capturing images of ink droplets ejected onto the substrate G. Ink droplets ejected onto the substrate G refer to ink droplets that have already adhered to the surface of the substrate G or are in the process of falling to adhere to the surface of the substrate G. The vision unit 43 can capture images that can confirm the ejection position of the ink droplets ejected onto the substrate G, the size of the ejected ink droplets, etc. In addition, the vision unit 43 can obtain images of the alignment mark AM, which will be described later.

[0055] Furthermore, the illumination device included in the visual unit 43 can be a polarized light illumination device. A polarized light illumination device can be an illumination device that includes a polarizing filter. Typically, the light emitted by an illumination device is a transverse wave whose electric and magnetic fields vibrate perpendicularly to each other and propagate forward. Most light in nature can be unpolarized light vibrating in various directions. The polarizing filter in a polarized light illumination device can allow only light vibrating in a certain direction to pass through.

[0056] The polarizing filter can be controlled to have different rotational positions when the vision unit 43 captures the alignment mark AM on the substrate G (described later) and when the imaging unit 50 captures the illumination mark LM (described later). Therefore, the polarizing illumination device can illuminate different forms of light. For example, when the vision unit 43 captures the alignment mark AM, the rotational position of the polarizing filter can be adjusted so that the polarizing illumination device illuminates unpolarized light onto the upper surface of the substrate G. Similarly, when the imaging unit 50 captures the illumination mark LM, the rotational position of the polarizing filter can be adjusted so that the polarizing illumination device illuminates polarized light.

[0057] Furthermore, when the imaging unit 50 (described later) captures images for calculating the distances OX and OY between the nozzle 42 and the vision section 43, the rotation position of the polarizing filter can be adjusted so that the polarizing illumination device illuminates polarized light. During the capture of the images for calculating the distances OX and OY, the polarizing filter rotates, causing the illuminated portion of the vision section 43 to appear as a black illumination mark LM in the image obtained by the imaging unit 50.

[0058] When the polarizing filter is rotated by a certain angle, in the image obtained by the imaging unit 50 (described later), the illuminated portion of the visual section 43 appears as a black illumination mark LM due to polarized light, while the remaining portion appears white due to light reflection. When the rotation angle of the polarizing filter is appropriately adjusted, the illuminated portion of the visual section 43 seen by the imaging unit 50 appears black, while the illuminated portion of the visual section 43 seen from other directions appears bright (white). When a polarized light illumination device including a polarizing filter is used, phenomena such as halo, glare, and reflection generated on the illuminated portion of the visual section 43 when the imaging unit 50 captures the image can be minimized. Therefore, when a polarized light illumination device is used, the imaging unit 50 (described later) can obtain an image of the illumination mark LM with higher precision.

[0059] The imaging unit 50 can be mounted on the maintenance unit 20. The imaging unit 50 may include a movable plate 51 and an imaging component 52. The imaging component 52 may be a camera. The imaging component 52 can capture images from above. The movable plate 51 can change position on the maintenance table 21 along the first direction X and / or the second direction Y via a moving mechanism such as a motor, guide rail, or guide block that moves along the guide rail, which can be configured on the maintenance table 21. Therefore, in order to calculate the distances OX and OY between the nozzle 42 and the vision section 43 (described later), when the imaging unit 50 captures images of the vision section 43, the movable plate 51 of the imaging unit 50 can change the position of the imaging component 52 between below the vision section 43 and below the nozzle 42.

[0060] The controller 60 can control the operation of the printing apparatus 1. The controller 60 can generate control signals for controlling the operation of the printing apparatus 1. The controller 60 may include: a process controller, consisting of a microprocessor (computer) for controlling the printing apparatus 1; a user interface, consisting of a keyboard or display for operator management of the printing apparatus 1, the keyboard for command input, and the display for visually displaying the driving status of the printing apparatus 1; and a storage unit storing a control program or procedure that causes the printing apparatus 1 to perform processes under the control of the process controller, the procedure causing each component to process according to various data and processing conditions. Additionally, the controller 60 may have a storage medium storing a program for enabling the printing apparatus 1 to perform the printing method described later. The storage medium may be a hard disk, a removable disk such as a CD-ROM / DVD, or a semiconductor memory such as flash memory.

[0061] The following describes the method by which the printing apparatus 1 of the present invention performs the printing step on the substrate G.

[0062] Figure 3 and Figure 4 This diagram illustrates the state in which the printing apparatus of the present invention performs the printing step on the substrate. (Refer to...) Figure 3 and Figure 4 The controller 60 can pre-select the levels of multiple nozzles N in the printhead unit 40 through a test spray previously performed in the maintenance unit 20. For example, the maintenance unit 20 may be equipped with a test unit (not shown) that provides test components such as test films, and the printhead unit 40 can spray ink droplets into the test unit. Furthermore, the vision unit 43 can capture images of the ink adhering to the test components. The images captured by the vision unit 43 can be transmitted to the controller 60. The controller 60 can determine the status of the multiple nozzles N in the printhead unit 40 based on the received images. For example, the multiple nozzles N in the printhead unit 40 can be managed hierarchically.

[0063] For example, a grade A nozzle N can be a nozzle where the ink droplet adhesion position, adhesion size, and adhesion are all good; a grade B nozzle N can be a nozzle N where two or more of the ink droplet adhesion position, adhesion size, and adhesion are good; a grade C nozzle N can be a nozzle N where only one of the ink droplet adhesion position, adhesion size, and adhesion is good; and a grade D nozzle N can be a nozzle where the ink droplet adhesion position, adhesion size, and adhesion are all poor. The poorly performing nozzles described below refer to the grade C or D nozzles N mentioned above.

[0064] Furthermore, the controller 60 considers the grades of the multiple nozzles N as described above and the desired ink film thickness (hereinafter referred to as the target thickness), and calculates the number of printing steps required for the printhead unit 40 to achieve the target thickness. Figure 3In the process, with the printhead unit 40 in the first position, the substrate G passes through the area below the printhead unit 40. During the passage of the substrate G through the area below the printhead unit 40, the printhead unit 40 ejects ink droplets onto the substrate G. This printing operation is defined as performing one printing operation. When one printing operation ends, the printhead unit 40 moves a set distance D along the first direction X and is located in the second position. With the printhead unit 40 in the second position, the substrate G passes through the area below the printhead unit 40. During the passage of the substrate G through the area below the printhead unit 40, the printhead unit 40 ejects ink droplets onto the substrate G. This printing operation is defined as performing a second printing operation.

[0065] That is, the controller 60 calculates the minimum number of printing steps required to achieve the target thickness. Furthermore, the required number of printing steps may vary depending on the printing requirements of the substrate G. Additionally, the printing steps can be performed sequentially from one side of the substrate G to the other. In each printing step, each print has a printing path, which, when viewed from above, can be arranged sequentially from one side of the substrate G to the other. In short, multiple printing steps can be performed sequentially from the right edge to the left edge of the substrate G. This reduces the time required for the printhead unit 40 to move between printing steps.

[0066] The printing method according to an embodiment of the present invention will now be described. The printing method described below can be implemented using a printing apparatus 1. Furthermore, the printing method described below can be implemented by controlling the components of the printing apparatus 1 using a controller 60 within the printing apparatus 1.

[0067] Figure 5 This is a flowchart illustrating a printing method according to an embodiment of the present invention.

[0068] Reference Figure 5 A printing method according to an embodiment of the present invention may include an illumination mark shooting step S1, a printhead shooting step S2, an offset calculation step S3, an alignment mark shooting step S4, and a printing step S5. The illumination mark shooting step S1, the printhead shooting step S2, the offset calculation step S3, the alignment mark shooting step S4, and the printing step S5 may be executed sequentially.

[0069] Figure 6 Is to show execution Figure 5 A diagram of the shooting unit for the lighting marker shooting steps.

[0070] Reference Figure 5 and Figure 6In the illumination mark imaging step S1, the imaging unit 50 can image the visual section 43. The imaging component 52 of the imaging unit 50 can be located below the visual section 43. Specifically, in the illumination mark imaging step S1, the illumination device of the visual section 43 can be imaged. The imaging component 52 images the visual section 43, and an image including the illumination mark LM can be obtained. When performing the illumination mark imaging step S1, the illumination device of the visual section 43 can be in an on state. Furthermore, the illumination device can illuminate polarized light. As described above, when the polarizing filter included in the illumination device is rotated to a certain angle, the illumination device of the visual section 43 can only transmit light vibrating in a certain direction.

[0071] Therefore, the illuminated area appears black, as... Figure 7 As shown, the marking is LM, while the rest is displayed in white. That is, by using the color contrast between the LM and the rest of the image achieved through the polarizing filter, the LM can be identified more accurately. Furthermore, by illuminating polarized light through the polarizing filter, when the imaging unit 50 acquires an image of the LM, phenomena such as reflections and halos near the LM can be minimized.

[0072] The controller 60 can calculate the position coordinates of the illumination mark LM based on the image containing the illumination mark LM and the current position coordinates of the imaging unit 50. For example, it detects the coordinates of the illumination mark LM within the image (specifically, the coordinates of the center of the illumination mark LM within the image) and calculates the position coordinates of the illumination portion of the vision unit 43 based on the current position coordinates of the imaging unit 50. Furthermore, the controller 60 can pre-store the distance between the illumination mark LM and the lens portion of the vision unit 43. Thus, the position coordinates of the lens portion of the vision unit 43 can be calculated simultaneously.

[0073] In short, the position coordinates of the vision unit 43 can be calculated based on the image containing the illumination marker LM and the current position coordinates of the imaging unit 50.

[0074] Figure 8 Is to show execution Figure 5 The image shows the shooting unit of the nozzle shooting process.

[0075] Reference Figure 5 and Figure 8 When the illumination mark imaging step S1 ends, the nozzle imaging step S2 can be executed. In the nozzle imaging step S2, the position of the nozzle unit 40 can remain unchanged, while the position of the imaging unit 50 can change. For example, the imaging unit 50 can move along the second direction Y and move towards the area below the nozzle 42 of the nozzle unit 40. In addition, the imaging unit 50 can capture an image of the lower part of the nozzle unit 40, thereby obtaining an image of the lower part of the nozzle 42.

[0076] The imaging unit 50 can capture images of nozzle N in the outermost nozzle 42 among the multiple nozzles 42 included in the nozzle unit 40. The nozzle N captured by the imaging unit 50 can be the aforementioned reference nozzle RN. The imaging unit 50 can obtain an image of the reference nozzle RN. Furthermore, the controller 60 can detect the coordinates of the reference nozzle RN within the image. Additionally, the position coordinates of the reference nozzle RN can be calculated based on the coordinates of the reference nozzle RN within the image and the current position coordinates of the imaging unit 50.

[0077] Figure 9 It is used to explain in Figure 5 The diagram shows the method for calculating the offset in the offset calculation steps.

[0078] Reference Figure 5 and Figure 9 In the offset calculation step S3, the distances OX and OY between the nozzle 42 and the visual part 43 can be calculated based on the position coordinates of the visual part 43 obtained through the illumination mark shooting step S1 and the position coordinates of the reference nozzle RN obtained through the nozzle shooting step S2.

[0079] The calculated spacings OX and OY can include a first measured spacing OX in the first direction X and a second measured spacing OY in the second direction Y. Furthermore, the controller 60 may pre-store a first reference spacing in the first direction X and a second reference spacing in the second direction Y. The first and second reference spacings can be normal spacing values ​​corresponding to the design values ​​of the printing apparatus 1.

[0080] Furthermore, the offset of the nozzle 42 can be confirmed by comparing the first measuring distance OX and the first reference distance, and by comparing the second measuring distance OY and the second reference distance. This offset can be represented by a first offset in the first direction X and a second offset in the second direction Y. The controller 60 can store the first and second offsets.

[0081] Figure 10 Is to show execution Figure 5 A diagram showing the state of the nozzle unit during the alignment and marking process.

[0082] Reference Figure 5 and Figure 10 The alignment mark imaging step S4 can be a step of aligning the position between the substrate G and the printhead unit 40 before the printhead unit 40 performs printing on the substrate G. At least one alignment mark AM is marked near the edge of the substrate G. The controller 60 can move the printhead unit 40 so that the vision unit 43 can capture the alignment mark AM marked on the substrate G. Alternatively, the controller 60 can control the printhead unit 40 or the transport fixture 12 so that the alignment mark AM on the substrate G seen through the vision unit 43 is aligned with the center of the vision unit 43.

[0083] Furthermore, in the alignment mark imaging step S4, the illumination device of the vision unit 43 may also be turned on. However, in the alignment mark imaging step S4, the light illuminated by the illumination device of the vision unit 43 can be unpolarized light. That is, the light illuminated by the illumination device of the vision unit 43 in the alignment mark imaging step S4 and the illumination mark imaging step S1 can be different types of light. In the alignment mark imaging step S4, if the polarizing filter is rotated by a certain angle as in the illumination mark imaging step S1, the illumination device may not be able to fully illuminate the alignment mark AM. At this time, the vision unit 43 may have difficulty effectively acquiring an image of the alignment mark AM.

[0084] Refer again Figures 3 to 5 In the printing step S5, when the alignment mark AM of the substrate G is aligned with the center of the vision section 43, the print head unit 40 can be moved by taking into account the relative positions of the vision section 43 and the print head 42, thereby adjusting the printing position of the print head 42.

[0085] When the printhead 42 is not offset, the printing position of the printhead 42 is adjusted by considering at least one of the first reference spacing and the second reference spacing. For example, when the printhead 42 is not offset, the printing position of the printhead 42 (i.e., the position of the printhead 42 in the first direction X during printing) can be adjusted by considering only the first reference spacing.

[0086] However, when the aforementioned first measurement spacing OX exceeds a critical value, the controller 60 adds an adjustment to the printing position of the printhead 42 based on a first offset. That is, the aforementioned set distance D value changes when based on the first offset.

[0087] Furthermore, when the aforementioned second offset exceeds a critical value, the controller 60 may consider the second offset to advance or delay the spraying timing of the multiple nozzles N of each nozzle 42 from the preset timing. For example, when considering the second offset, if it is determined that the substrate G enters the area below the nozzle 42 later, the spraying timing can be delayed; if it is determined that the substrate G enters earlier, the spraying timing can be advanced.

[0088] Furthermore, the timing of this spraying can be set differently depending on the direction of movement of the substrate G. For example, as Figure 3 As shown, when the substrate G moves in the second direction Y, specifically in the forward direction, the spraying timing can be preset by a value, such as... Figure 4 As shown, when the substrate G moves in the second direction Y, specifically in the backward direction, the ejection timing can be delayed by the aforementioned setting value. The positional offset of the printhead unit 40 may cause the ink droplet attachment position to shift forward or backward depending on the direction in which the substrate G enters.

[0089] As described above, in the alignment mark imaging step S4, the relative positions of the printhead unit 40 and the substrate G are adjusted based on the image captured by the vision unit 43. This is because the aforementioned spacings OX and OY are calculated based on the vision unit 43. That is, since the original spacings OX and OY are calculated based on the vision unit 43, even if the vision unit 43 itself shifts position, the ink can still be smoothly adhered to the accurate position by adjusting the printing position of the printhead 42 through the spacings OX and OY.

[0090] The present invention can use the illumination mark LM to calculate the distance OX and OY between the vision section 43 and the print head 42, thereby avoiding the printing position displacement of the print head 42 due to the position displacement of the vision section 43.

[0091] Furthermore, when additional physical labels are marked or affixed to the printhead unit 40, these labels may not be marked or affixed in the accurate position. With the increasing demands for precision in display manufacturing processes in recent years, printing position needs to be precisely controlled at the micrometer level. If the aforementioned physical labels are incorrectly marked or affixed, precise control of the printing position becomes impossible. Additionally, the physical labels may become contaminated during the process, making precise control of the printhead 42's printing position difficult. However, as described above, the present invention utilizes an illuminating marker (LM), thereby simultaneously solving the problems that may arise from marking or affixing additional physical labels to the printhead unit 40.

[0092] Furthermore, in this invention, by comparing the measured distance between the vision unit 43 and the printhead 42 measured by the imaging unit 50 with the pre-stored design distance, i.e., the reference distance, the difference is derived as a first offset and a second offset. The printing position of the printhead 42 is adjusted based on the derived first offset and second offset. Therefore, even if the position of the printhead 42 is offset, the ink droplets can be attached to the accurate position.

[0093] In the example above, although it is illustrated that the distance OX and OY between a reference nozzle RN and the vision unit 43 are measured in the offset calculation step S3, the offset is calculated therefrom, but it is not limited to this.

[0094] For example, such as Figures 11a to 11dAs shown, in the offset calculation step S3, the distances between the reference nozzles RN1, RN2, RN3, and RN4 in all nozzles 42 and the vision unit 43 can be calculated. For example, the first measurement distance OX1 and the first measurement distance OX1 between the first nozzle 42-1 and the vision unit 43, the second measurement distance OX2 and the second measurement distance OX2 between the second nozzle 42-2 and the vision unit 43, the third measurement distance OX3 and the third measurement distance OX3 between the third nozzle 42-3 and the vision unit 43, and the fourth measurement distance OX4 and the fourth measurement distance OX4 between the fourth nozzle 42-4 and the vision unit 43 can be measured respectively.

[0095] Furthermore, the offset can be calculated by comparing the measured distance with the reference distance pre-stored by the controller 60. In this way, the controller 60 can confirm whether there has been an offset in the relative position between the vision unit 43 and the first to fourth nozzles 42-1, 42-2, 42-3, and 42-4.

[0096] Next, as Figure 12 During printing, the controller 60 can adjust the spray timing of each of the first to fourth printheads 42-1, 42-2, 42-3, and 42-4 based on previously calculated offsets. That is, the spray timing of each of the first to fourth printheads 42-1, 42-2, 42-3, and 42-4 can be adjusted independently of each other based on the offsets.

[0097] Furthermore, the controller 60 can select the nozzles for printing from each of the first to fourth printheads 42-1, 42-2, 42-3, and 42-4 based on previously calculated offsets. For example, it is difficult to adjust the positions of the first to fourth printheads 42-1, 42-2, 42-3, and 42-4 in the first direction X individually. Each printhead 42 is equipped with multiple nozzles N, and different nozzles can be used when the positional offset described above occurs. For example, if printing was originally performed using the first to eighth nozzles N, when a positional offset occurs in a particular printhead 42, the aforementioned offset can be taken into account, and printing can be performed using the third to tenth nozzles N.

[0098] The above example illustrates that the maintenance section 20 is arranged relative to the printing section 10 along the first direction X, but it is not limited thereto. For example, as Figure 13 As shown, the maintenance unit 20 can also be configured relative to the printing unit 10 along the second direction Y. In this case, the gantry 30 can be configured to move along the second direction Y, so that the printhead unit 40 can move between the printing unit 10 and the maintenance unit 20.

[0099] In the example above, it is illustrated that the visual part 43 is attached to the housing 41 along the second direction Y, but it is not limited thereto. For example, as Figure 14 As shown, the vision unit 43 can be configured to be attached to the housing 41 along the first direction X.

[0100] The above detailed description is for illustrative purposes only. Furthermore, the foregoing content is intended to describe preferred embodiments of the invention, which can be implemented in various combinations, variations, and usage environments. That is, modifications or variations can be made within the scope of the inventive concept disclosed in this specification, within the equivalent scope of the disclosed content, and / or within the scope of the relevant technical or knowledge field. The described embodiments are intended to illustrate the optimal implementation state for realizing the technical idea of ​​the invention, and various variations can be made according to the specific application field and use of the invention. Therefore, the detailed description of the invention is not intended to limit the scope of protection to the disclosed embodiments. The claims should be interpreted to cover other embodiments.

Claims

1. A method for printing on a substrate, the method comprising: The illumination mark imaging step involves positioning the imaging component below the visual section of the nozzle unit, and with the illumination device in the visual section turned on, the imaging component images the visual section to obtain an image containing the illumination mark. The nozzle imaging step involves positioning the imaging component below the nozzle of the nozzle unit and obtaining an image of the lower part of the nozzle. as well as The offset calculation step involves measuring the distance between the nozzle and the vision unit, and calculating the offset based on the measured distance.

2. The printing method according to claim 1, further comprising: In the printing step, the printing position of the printhead unit for ejecting ink droplets onto the substrate is adjusted based on the offset, and the ink droplets are ejected onto the substrate using the printhead unit with the adjusted printing position.

3. The printing method according to claim 2, further comprising: In the printing step, the timing of ejecting ink droplets onto the substrate is adjusted based on the offset, and the ink droplets are ejected onto the substrate using the printhead unit with the adjusted ejection timing.

4. The printing method according to claim 3, wherein, The timing of the injection is controlled to be advanced or delayed depending on the direction of movement of the substrate.

5. The printing method according to claim 4, wherein, When the substrate moves forward in the second direction, the spraying timing is preset. When the substrate moves backward in the second direction, the timing of the spraying is delayed by the set value.

6. The printing method according to claim 2, wherein, Prior to performing the printing step, the method further includes: In the alignment mark imaging step, the vision unit images the alignment marks marked on the substrate.

7. The printing method according to claim 6, wherein, During the alignment mark shooting step, the visual part and the alignment mark are aligned.

8. The printing method according to claim 1, wherein, The nozzle unit moves in a first direction, and the substrate moves in a second direction. The spacing includes: The first measurement interval in the first direction; and The second measurement interval in the second direction, The first measurement interval and the second measurement interval are compared with the pre-stored first reference interval and second reference interval, respectively, to calculate the first offset and the second offset.

9. The printing method according to claim 8, wherein, The printing position of the printhead unit is adjusted based on either the first offset or the second offset. The timing of ink droplet ejection by the printhead unit is adjusted based on the other of the first offset and the second offset.

10. The printing method according to claim 2, wherein, The visual unit includes a polarized light illumination device with a polarizing filter.

11. The printing method according to claim 10, wherein, Prior to performing the printing step, the method further includes: In the alignment mark imaging step, the vision unit images the alignment marks marked on the substrate. In the alignment mark shooting step and the illumination mark shooting step, the type of light irradiated by the polarized light illumination device is different.

12. The printing method according to claim 11, wherein, The polarized light illumination device is configured as follows: During the alignment mark imaging step, unpolarized light is irradiated. Polarized light is irradiated during the illumination mark shooting step.

13. A method for controlling a printing apparatus, wherein, The printing apparatus includes a printing table for performing printing steps on a substrate, a transport unit for transporting the substrate along the printing table, a printhead unit for ejecting ink droplets onto the substrate transported by the transport unit, and an imaging unit for photographing the printhead unit. The printhead unit includes a printhead having a nozzle that ejects the ink droplets, and a vision unit spaced apart from the printhead and including an illumination device. The control method includes: With the illumination device of the visual section turned on, the imaging unit captures images of the nozzle and the visual section to measure the distance between the nozzle and the visual section.

14. The control method for the printing apparatus according to claim 13, the control method comprising: Calculate the difference between the measured spacing and the pre-stored reference spacing, wherein the difference between the measured spacing and the pre-stored reference spacing is the offset.

15. The control method for the printing apparatus according to claim 14, the control method comprising: The position at which the printhead ejects the ink droplets onto the substrate is adjusted based on the offset, wherein the position at which the printhead ejects the ink droplets onto the substrate is the printing position.

16. The control method for the printing apparatus according to claim 15, the control method comprising: The vision unit captures alignment marks marked on the substrate and aligns the nozzle unit relative to the substrate based on the image containing the alignment marks.

17. The control method for the printing apparatus according to claim 14, the control method comprising: The timing of the printhead ejecting ink droplets onto the substrate is adjusted based on the offset, wherein the timing of the printhead ejecting ink droplets onto the substrate is the ejection timing.

18. The control method for a printing apparatus according to claim 17, wherein, The nozzles are configured as multiple. Measure the spacing for each nozzle separately. Calculate the offset for each nozzle separately. The spray timing of each nozzle is adjusted independently based on its offset.

19. An inkjet device comprising: The printing department performs printing steps on the substrate; The maintenance section is arranged side by side with respect to the printing section along a first direction; The gantry is configured to extend along the first direction when viewed from above, and pass through the printing section and the maintenance section; A printhead unit, mounted on the gantry and movably configured along the first direction, ejects ink droplets onto the substrate; A camera unit, located in the maintenance unit, is used to photograph the nozzle unit. as well as Controller The printing section includes: A printing stage that sprays gas onto the lower surface of the substrate to suspend the substrate; and The conveying unit moves the suspended substrate in a second direction perpendicular to the first direction. The nozzle unit includes: case; Multiple nozzles are disposed within the housing; and The vision unit is disposed in the housing. The controller is configured to, The camera unit is controlled to capture images of the visual section while the illumination device of the visual section is on, and the camera unit is moved to capture images of the lower part of the nozzle. The distance between the visual unit and the nozzle is measured based on the captured image. The difference between the measured spacing and the pre-stored reference spacing is calculated by comparing the measured spacing with the reference spacing, wherein the difference between the spacing and the reference spacing is the offset. The printhead unit is controlled to adjust the position of the printhead ejecting the ink droplets onto the substrate based on the calculated offset, wherein the position of the printhead ejecting the ink droplets onto the substrate is the printing position.

20. The inkjet apparatus according to claim 19, wherein, The controller is configured to, The conveying unit and the printhead unit are controlled so that the printhead, whose printing position is adjusted, sprays ink droplets onto the upper surface of the substrate conveyed by the conveying unit.

Images