KR102237721B1 - Inkjet printing apparatus - Google Patents

Abstract

The present invention relates to an inkjet printing device, which is moved to a second position after controlling an inkjet head to primary jetting operation at a first position when the inkjet head comprises at least one abnormal nozzle and at least one normal nozzle and controls secondary jetting operation of discharging a droplet by replacing the normal nozzle by the abnormal nozzle at the second position to normally apply the droplet on a substrate regardless of replacement even though the inkjet head has defects.

Description

Inkjet printing device {INKJET PRINTING APPARATUS}

This document relates to an inkjet printing apparatus, and specifically, relates to a technique for efficiently controlling the movement and jetting of a defective inkjet head having a normal nozzle and an abnormal nozzle.

Recently, a display device using an organic light emitting diode (OLED) is attracting attention.

The organic light-emitting display device has a self-emission characteristic, and unlike a liquid crystal display device, since it does not require a separate light source, thickness and weight can be reduced. The organic light emitting diode display exhibits high quality characteristics such as low power consumption, high luminance, and fast reaction speed.

In the case of applying UV ink or a color filter on a substrate to manufacture such an organic light emitting display device, a printing device having an inkjet head, that is, a droplet ejection printer is used.

In the process of using the inkjet head, the droplet must be smoothly discharged from a plurality of nozzles provided in the inkjet head. If any one of the plurality of nozzles does not smoothly discharge the droplets, it leads to a process failure, and thus the inkjet head must be replaced, resulting in a problem of high cost and delay in working time.

Korean Patent Publication (Registration Publication No.: 10-1657530, "Drop Discharge Device and Method") discloses that when an abnormality occurs in any one or more of the plurality of nozzles of the first inkjet head, the liquid is transferred to the substrate instead of the first inkjet head. Including a second inkjet head that is provided to be arranged for each area in which the first inkjet head is disposed so that the droplets can be discharged, and when the droplets are discharged to the substrate using the second inkjet head, the droplets are aligned so as to correspond to the first inkjet head. In addition, a technique for solving a defect in a nozzle provided in the first inkjet head by discharging droplets more than twice in a portion corresponding to a nozzle in which an abnormality occurs in the first inkjet head is disclosed. However, no technology has been disclosed for solving by efficiently controlling the printing drive of the first inkjet head itself without the aid of the second inkjet head.

An object of the present invention is to control the movement and jetting of a defective inkjet head having a normal nozzle and an abnormal nozzle so that a complete and normal droplet application can be achieved on a substrate without replacing the head.

An inkjet printing apparatus according to an aspect for achieving this object includes a plurality of nozzles, an inkjet head that moves on a substrate and performs jetting driving to discharge droplets through the nozzles at a specific position, and

It includes a control unit that is electrically connected to the inkjet head and controls the movement and jetting driving of the inkjet head,

The inkjet head,

Having at least one abnormal nozzle and at least one normal nozzle,

The control unit,

After controlling the inkjet head to perform the first jetting drive at the first position, it moves to the second position, and the normal nozzle replaces the abnormal nozzle at the second position to discharge droplets. By controlling to perform the second jetting drive, complete droplet application can be achieved on the substrate.

The present invention enables complete droplet application on the substrate even when a specific nozzle is abnormal in which droplets are not discharged smoothly, so that there is no need to replace the inkjet head, thereby reducing cost and delaying the operation time due to the replacement. Can be prevented. In addition, the number of jetting of the inkjet head or the moving time of the inkjet head can be reduced, thereby further reducing the working time.

1 is a diagram illustrating an inkjet printing apparatus according to an exemplary embodiment.
2 is a diagram illustrating functions of an inkjet head unit and a control unit of an inkjet printing apparatus according to an exemplary embodiment.
3 is a view for explaining determining a second position for a second jetting drive of an inkjet printing apparatus according to another exemplary embodiment.
4 is a block diagram illustrating again the contents of FIG. 3 relating to the inkjet printing apparatus.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily understand and reproduce the present invention through preferred embodiments described with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the embodiments of the present invention, the detailed description thereof will be omitted. Terms used throughout the specification of the present invention are terms defined in consideration of functions in the embodiments of the present invention, and can be sufficiently modified according to the intention and custom of a user or operator, so the definitions of these terms are defined throughout the present specification. It will have to be made based on the contents of

In addition, the above-described and additional aspects of the invention will become apparent through the following embodiments. Aspects or configurations of the embodiments that are selectively described in the present specification may be freely combined with each other, unless otherwise indicated, unless otherwise indicated, unless otherwise indicated, even if they are shown as a single integrated configuration, they may be freely combined with each other unless it is obvious that there is a technical contradiction to the person skilled in the art. I understand.

Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations. For example, the meaning of droplet in this specification includes not only ink droplets but also optically clear resin (OCR) droplets.

1 is a diagram illustrating an inkjet printing apparatus 100 according to an exemplary embodiment. As shown, the inkjet printing apparatus 100 includes a stage 10, a gantry scale 20, a gantry 30, a droplet supply unit 40, a head unit 50, a head 51, and a rail ( 60), may be configured to include a maintenance unit (70).

The stage 10 supports an object to print the droplets 2, that is, a substrate, and can move back and forth. The substrate may include an organic light emitting display panel 1 or a protective cover 3. The gantry stage 20 functions to support the gantry 30 and the maintenance unit 70. The gantry 30 serves to support the head unit 50 and the droplet supply unit 40, and the head unit 50 receives droplets 2 from the droplet supply unit 40 and dispenses them onto the substrate. . The droplet supply unit 40 does not need to be mounted on the gantry 30 and may be present in the inkjet head unit 50.

The inkjet head unit 50 has a head underneath, and the head 51 has tens to thousands of nozzles 52 so that droplets can be dispensed (jetted) while moving according to a program stored in advance. The programming data is stored in a memory unit (not shown), and the operation and dispensing operation (eg, discharge amount, frequency, and speed) of the head unit 50 may be controlled by a control unit (not shown). The inkjet head unit 50 may move in a direction perpendicular to the stage 10 by the rail 60. The maintenance unit 70 performs a function for maintenance and repair of the inkjet head 51.

2 is a diagram illustrating functions of an inkjet head unit and a control unit of an inkjet printing apparatus according to an exemplary embodiment. As shown, the inkjet printing apparatus 100 may include an inkjet head unit 50 and a control unit 80. The inkjet head unit 50 includes a plurality of inkjet heads 51, and the inkjet head 51 includes a plurality of nozzles 52.

An inkjet printing apparatus according to an embodiment includes a plurality of nozzles 52, an inkjet head 51 that moves on a substrate and discharges droplets through a nozzle at a specific position, and is electrically connected to the inkjet head. It includes a control unit 80 connected to control the movement of the inkjet head and the jetting drive of the inkjet head,

The inkjet head,

Having at least one abnormal nozzle and at least one normal nozzle,

The control unit,

After controlling the inkjet head to perform the first jetting drive at the first position, it moves to the second position, and at the second position, the normal nozzle replaces the abnormal nozzle and discharges droplets. It can be controlled to perform the secondary jetting drive.

The inkjet head unit 50 is supported by a gentry 30 of the inkjet printing apparatus 100 and performs a translational motion (in the direction of an arrow) along the rail 60 to jet and discharge droplets onto the display substrate. The head unit is electrically connected to the control unit (solid line), receives a control signal from the control unit, and performs translational motion through a motor (not shown). Each head is electrically connected (dotted line) to the control unit so that droplets may be jetted through the nozzle.

The inkjet head 51 includes a plurality of nozzles 52, moves on a substrate, and performs jetting driving in which droplets are discharged from a specific position through the nozzle 52. When the inkjet head unit 50 moves, the inkjet head 51 moves together and the nozzle 52 moves together. The arrangement of the inkjet head 51 may vary.

Droplets are discharged through the nozzle, and when a foreign substance is caught in the nozzle, when the hardened droplet blocks the nozzle, or when the jetting is not driven, there is a defect in the nozzle. Jetting (dispensing) may be a method of pushing a droplet out of a nozzle by applying a voltage using a piezo-electric method.

The inkjet head 51 may include at least one abnormal nozzle and at least one normal nozzle. As shown, in the case of the inkjet head 52A, the nozzle N1 is an abnormal nozzle, and the remaining seven nozzles including N2 are normal nozzles.

The controller 80 may be electrically connected to the inkjet head to control driving of the inkjet head. That is, the control unit 80 may move the inkjet head unit so that the inkjet head moves together, and droplets may be individually discharged from the nozzle 52 of the inkjet head 51.

The control unit 80 controls the inkjet head 51 to perform a first jetting drive that discharges droplets from the first position, and then the normal nozzle moves to the second position where the abnormal nozzle was located, and The nozzle may be controlled to replace the abnormal nozzle and perform the second jetting drive for discharging droplets. For example, when a droplet is not discharged from the inkjet head 52A due to an abnormality in the nozzle N1, the control unit 80 first performs a first jetting drive, and then moves the inkjet head unit 50 to cause the nozzle N2 to It is possible to control to move to the position of the nozzle N1 (the second position), and to perform additional jetting (second jetting) driving by replacing the nozzle N1 with the nozzle N2. It is preferable that the second jetted normal nozzle is a nozzle closest to the abnormal nozzle. As shown, it is preferable that the nozzle N2 moves to the position of the nozzle N1 to be replaced. This shortens the travel distance and reduces the overall printing time. If the nozzles N1 and N2 are abnormal, N3 and N4 can be replaced.

The meaning of'replacement' means that the normal nozzle moves to the position of the abnormal nozzle so that droplets can be discharged in place of the abnormal nozzle. N2 functions as a substitute.

3 is a view for explaining determining a second position for a second jetting drive of an inkjet printing apparatus according to another exemplary embodiment. As shown, FIG. 3(a) shows the nozzle state of a specific head, FIG. 3(b) shows the nozzle used for the first jetting drive, and FIG. 3(c) shows the second The second position of the inkjet head for driving the vehicle jetting and the priority of the position are shown.

As shown in (a) of FIG. 3, the inkjet head is equipped with eight nozzles, of which nozzle N2, nozzle N4, nozzle N7, and nozzle N8 are normal nozzles O, while medium nozzle N1, The nozzles N3, N5, and N6 are abnormal nozzles X in which droplets are not discharged or are not smooth.

As shown in (b) of FIG. 3, the first jetting drive jets the normal nozzles N2, N4, N7, and N8 (block display). That is, nozzles used for the first jetting drive are N2, N4, N7, and N8. Accordingly, droplets may be discharged and applied to an area of the substrate located below the normal nozzle. The position of the inkjet head where the first jetting drive is performed becomes the first position.

As shown in FIG. 3C, in determining the second position for the second jetting drive, the second position is determined based on the first position. Droplets applied to positions on the substrate corresponding to the first position were applied only to positions corresponding to normal nozzles (N2, N4, N7, N8), and positions corresponding to abnormal nozzles (N1, N3, N5, N6) Not applied. Therefore, it is necessary to move the inkjet head so that the normal nozzle replaces the abnormal nozzle, and the number of cases in which the inkjet head can be positioned may be 13, as shown.

When the inkjet head is moved to the position of (1), the nozzle N8 can replace the nozzle N1, and when the inkjet head is moved to the position of (2), the nozzle N7 can replace the nozzle N1, and the inkjet head is ( When moved to the position of 3), nozzle N8 can replace nozzle N3. As described above, when the inkjet head moves to the positions of (1), (2), (3), and (4), it can be seen that only one abnormal nozzle can be replaced. Similarly, it can be seen that only one abnormal nozzle can be replaced even when the inkjet head is moved to the positions of (10)-(13), and that the position of (8) cannot replace any abnormal nozzles. Able to know.

On the other hand, when the inkjet head moves to the positions of (5), (6), and (9), it can be seen that the normal nozzle can replace the two abnormal nozzles.

In addition, when the inkjet head moves to the position of (7), it can be seen that the normal nozzles (N2, N4, N7, N8) can replace the three abnormal nozzles (N1, N3, N6).

Therefore, it can be seen that the position of (7) that can replace the most abnormal nozzles with one movement of the inkjet head is the position of (5), (6), and (9).

When scoring the positions of each inkjet head based on the replaceable abnormal nozzle, the positions of (7) are 3 points, the positions of (5), (6), and (9) are 2 points, The positions of (1)-(4), (10)-(13) can be scored with 1 point and the position of (8) with 0 points. A separate calculation unit (not shown) is provided for scoring to perform this.

In the inkjet printing apparatus according to an exemplary embodiment, the controller 80 may determine a position where the largest number of normal nozzles can replace abnormal nozzles as the second position. The controller 80 may sequentially move the inkjet head according to the priority of the position calculated based on the scoring data. In other words, the control unit determines the area in which the highest score appears as the second position by assigning a score to the normal nozzle, excluding the area where the first jetting drive and the droplets are applied on the substrate, and at the second position. It is possible to control the jetting of the inkjet head.

That is, the second position may be a position in which the largest number of normal nozzles can replace abnormal nozzles. In Fig. 3, the second position is the position (7).

After the inkjet head moves to the second position, the control unit moves the inkjet head to a third position where the next largest number of normal nozzles than the largest number can replace the abnormal nozzle. You can control it to move. In Fig. 3, the third position is the positions (5), (6), and (9).

In the inkjet printing apparatus according to an embodiment, when there are a plurality of third positions, the controller may determine a position having the shortest moving distance of the inkjet head as the third position. In the case of FIG. 3, it can be seen that the position of (6) has the shortest moving distance among the positions of (5), (6), and (9). This is because you only need to move the inkjet head one nozzle to the left. Accordingly, the control unit can determine the position of (6) as the third position.

Likewise, even when there are a plurality of second positions, a position having the shortest moving distance of the inkjet head may be determined as the second position.

FIG. 4 is a diagram for re-explaining the contents of FIG. 3 in a different manner in the inkjet printing apparatus according to an exemplary embodiment. As shown in (a) of FIG. 4, the (ink jet) head constitutes eight nozzles, of which nozzle N2, nozzle N4, nozzle N7, and nozzle N8 are normal nozzles (O). The middle nozzle N1, the nozzle N3, the nozzle N5, and the nozzle N6 are abnormal nozzles X from which droplets are not discharged.

As shown in (b) of FIG. 4, the first jetting drive jets the normal nozzles N2, N4, N7, and N8 (block display). Accordingly, droplets may be discharged and applied to an area of the substrate located below the normal nozzle. The position of the inkjet head where the first jetting drive is performed becomes the first position. According to the first jetting, it was applied (printed) to a position on the substrate corresponding to the position of the normal nozzles N2, N4, N7, and N8.

In the second jetting drive, the inkjet head moves to the left as much as one nozzle, and the normal nozzles N2, N4, N7 in the second position replace the three abnormal nozzles (N1, N3, N6) in the first position. do. According to the second jetting, it was applied (printed) to a position on the substrate corresponding to the position of the normal nozzles N2, N4, and N7. Normal nozzles N2, N4, and N7 perform the function of substitution in the second jetting.

However, since the nozzle N6 is an abnormal nozzle, it cannot replace the abnormal nozzle N5 at the position of (7) (the second position), so additional movement and additional jetting driving are required. The additional jetting drive, that is, the third jetting drive, allows the normal nozzle N2 at the position where the inkjet head has moved to the right by 3 nozzles (the third position) to replace the abnormal nozzle N5 at the second position. . Of course, as described above, even if the inkjet head is moved to the left by one nozzle (position of FIG. 3 (6)), the same effect can be obtained, and in this case, the moving distance of the inkjet head can be shortened.

Accordingly, in the inkjet printing apparatus according to an embodiment, a position at which the next largest number of normal nozzles can replace abnormal nozzles compared to the'most number' is determined as the third position, It is possible to control the inkjet head to move to the third position.

As a result, four of the eight nozzles were abnormal, but only two additional jettings (second jetting and third jetting) resulted in a complete application.

In the inkjet printing apparatus according to an embodiment, there may be additional jetting beyond the fourth jetting.

10: stage
20: Gantry Stage
30: gantry
40: droplet supply unit
50: head unit
51: head
60: rail
70: maintenance section
50: inkjet head unit
51: inkjet head
52: nozzle
80: control unit
100: inkjet printing device

Claims (5)

An inkjet head having a plurality of nozzles, moving on a substrate and performing jetting driving for discharging droplets through the nozzles at a specific position; And
Includes; a control unit electrically connected to the inkjet head to control movement of the inkjet head and jetting driving of the inkjet head,
The inkjet head,
Having at least one abnormal nozzle and at least one normal nozzle,
The control unit,
After controlling the inkjet head to perform the first jetting drive at the first position, it moves to the second position and replaces the abnormal nozzle with the'largest number' of normal nozzles at the second position. ) To perform the second jetting drive for discharging droplets, but when there are a plurality of second positions, the position of the inkjet head having the shortest movement distance is determined as the second position,
Then, a position at which the next largest number of normal nozzles can replace abnormal nozzles compared to the'most number' is determined as a third position, and the inkjet head moves to the third position. An inkjet printing apparatus that controls to move, but determines a position having the shortest moving distance of the inkjet head as the third position when there are a plurality of third positions. delete delete delete delete

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