JP2022061890A - Maintenance method and maintenance device of ink discharge head - Google Patents

Abstract

To perform maintenance of removing clogging or a deposition in a nozzle by eliminating a harmful effect on ink flight without damaging a nozzle surface.SOLUTION: A maintenance method of an ink discharge head includes an immersing step of immersing a nozzle surface of the ink discharge head into cleaning liquid input to a cleaning tank, a suction step of draining the cleaning liquid in the cleaning tank and sucking in the cleaning tank to suck and remove the cleaning liquid adhered to the nozzle surface and remove clogging in the nozzle in the ink discharge head, and a liquid suction step of bringing a liquid suction sheet into contact with the nozzle surface to suck and remove residual liquid in the nozzle surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a maintenance method and a maintenance device for an ink ejection head in an inkjet printer or a dispenser device.

Liquid material ejection devices such as inkjet devices and dispenser devices are used in various fields such as printing, painting, and application / injection of liquid materials. Particularly in recent years, in the field called printed electronics, an inkjet device has been used when forming a circuit pattern using conductive ink as a liquid material. Such an ejection device includes an ink ejection head that ejects a liquid material (ink) by various drive methods such as a piezoelectric method, a thermal method, an air pulse method, and a wave method, depending on the application.

Further, in the field of printable electronics described above, a technique for ejecting ink in all directions (omnidirectional inkjet (OIJ) printing technique, etc.) assuming that the work to be ejected ink has a three-dimensional curved surface. ) Is being studied. In such a technique, the ink ejection head is held by a multi-axis articulated robot so that the direction of the ink ejection head can be changed by 360 °, and the multi-axis articulated robot moves the height of the ink ejection head in the horizontal plane. The position and angle are controlled independently (see Patent Document 1 below).

Since the ink ejection head ejects ink, which is a liquid material, from the nozzle by various methods, clogging of the nozzle becomes a problem. Generally, a cleaning mechanism is adopted to solve this problem. The conventional cleaning mechanism has a wiper for scraping off dirt adhering to the vicinity of the nozzle of the ink ejection head, a mechanism for sucking out air bubbles in the nozzle and high-viscosity ink from the nozzle side, or a mechanism for pushing out ink from the supply side. (See Patent Document 2 below).

Japanese Patent No. 6482914 Japanese Unexamined Patent Publication No. 3-99857

In the conventional cleaning mechanism, when the ink contains particles such as metal like conductive ink, the particles attached to the nozzle surface of the ink ejection head rub the nozzle surface by the operation of the wiper, and the ink There is a problem that the nozzle surface of the discharge head is damaged. Then, when the nozzle surface is scratched, it has been confirmed that the ink droplets do not fly straight due to the capillary phenomenon caused by the scratches.

Further, if the contact pressure of the wiper with respect to the nozzle surface is reduced so as not to cause scratches, the particles contained in the ink may not be completely removed only by the operation of the wiper. If particles or particles remain on the nozzle surface or near the nozzle outlet, this may cause problems such as ink flight impossibility and variation in the flight direction.

An object of the present invention is to deal with such a problem. That is, it is an object of the present invention to perform maintenance for removing clogging and deposits of the nozzle without damaging the nozzle surface and eliminating an adverse effect on ink flight.

In order to solve such a problem, the present invention has the following configurations.

By immersing the nozzle surface of the ink ejection head in the cleaning liquid injected into the cleaning tank and draining the cleaning liquid from the cleaning tank and sucking the inside of the cleaning tank, the cleaning liquid adhering to the nozzle surface is removed. It has a suction step of removing the clogging of the nozzle in the ink ejection head and a liquid absorbing step of contacting the nozzle surface with a liquid absorbing sheet to remove the residual liquid on the nozzle surface. A maintenance method for the ink ejection head, which is characterized by this.

It is a maintenance device for the ink ejection head, and is provided with a cleaning tank into which the cleaning liquid for immersing the nozzle surface of the ink ejection head is injected. An ink ejection head maintenance device characterized by being connected to a drainage / suction flow path that drains the cleaning liquid and sucks the inside of the tank.

Explanatory drawing which shows the maintenance method of an ink ejection head. Explanatory drawing which shows the maintenance apparatus of an ink ejection head. Explanatory drawing explaining the dipping step (see (a)) and the suction step (see (b)). Explanatory drawing which shows the liquid absorption sheet unit and the liquid absorption process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different figures indicate parts having the same function, and duplicate description in each figure will be omitted as appropriate.

As shown in FIG. 1, the maintenance method of the ink ejection head according to the embodiment of the present invention includes a dipping step S1, a suction step S2, a liquid absorbing step S3, and a trial striking step S4. In these steps, the steps other than the dipping step S1 and the suction step S2 can be omitted as necessary.

Maintenance of the ink ejection head having each of the above-mentioned steps is appropriately performed before the inkjet device or the dispenser apparatus ejects ink from the ink ejection head to perform a series of printing operations. For example, a series of printing operations is executed. It is also performed later, such as before starting the next printing operation. The maintenance here is performed on the nozzle surface of the ink ejection head, removes deposits on the nozzle surface and clogging of the nozzle, and returns the flying state of the ink ejected from the nozzle to a normal state. As described above, when performing omnidirectional inkjet printing, the flying state of ink due to gravity differs in each direction, so a correction step for correcting this is performed before a series of printing operations. By performing the maintenance in the previous stage of this correction step, the effect of the correction can be enhanced, and a stable and accurate ink flight state can be maintained.

A device configuration for executing the above-mentioned maintenance method will be described with reference to FIG. 2. Explaining the case of performing omnidirectional inkjet printing as an example, the ink ejection head H is supported by the arm tip of a multi-axis articulated robot (not shown) and can move in any position and direction for maintenance. Even at times, the processing of each step is performed on the nozzle surface Ha of the ink ejection head H while being supported by the multi-axis articulated robot.

As a device for executing the maintenance method, a cleaning tank 10 and a liquid absorbing sheet unit 20 are arranged on the support surface F. The cleaning tank 10 is above it as a standby position for the ink ejection head H during maintenance, and is provided with an inner tank 11 into which the cleaning liquid is injected and an outer tank 11 in which the cleaning liquid is poured onto the nozzle surface Ha and receives the cleaning liquid overflowing from the inner tank 11. It has a two-tank structure consisting of a tank 12. The liquid absorbing sheet unit 20 is provided with a mechanism for bringing the liquid absorbing sheet T into contact with the nozzle surface Ha.

Further, as an apparatus for executing the maintenance method, a cleaning liquid supply unit 30 and a gas-liquid separation box 40 are provided. The cleaning liquid supply unit 30 includes a cleaning liquid tank 31 in which the cleaning liquid is stored. The cleaning liquid tank 31 is connected to the inner tank 11 of the cleaning tank 10 via the flow path (piping) a and the flow path b. Further, the inner tank 11 of the washing tank 10 is connected to the gas-liquid separation box 40 via the flow path b, the flow path c, and the flow path d. The outer tank 12 of the washing tank 10 is connected to the gas-liquid separation box 40 via the flow path e. An ejector 50 is provided between the flow path c and the flow path d.

In each of the above-mentioned flow paths, the valve V3 of the flow path c is closed and the valve V1 of the flow path a and the valve V2 of the flow path b are opened, so that the cleaning liquid from the cleaning liquid tank 31 to the inner tank 11 of the cleaning tank 10 is reached. An injection flow path is formed, and this cleaning liquid injection flow path is connected to the inner tank 11. Further, by closing the valve V1 of the flow path a and opening the valve V2 of the flow path b and the valve V3 of the flow path c, the drainage / suction flow path from the inner tank 11 of the cleaning tank 10 to the gas-liquid separation box 40 is reached. Is formed, and one of the drainage / suction flow paths is connected to the inner tank 11. The flow path e is a drainage flow path for draining the cleaning liquid overflowing in the outer tank 12 of the cleaning tank 10 into, for example, a gas-liquid separation box 40.

The ejector 50 positively circulates the drainage in the drainage / suction flow path described above, and also performs suction in the drainage / suction flow path to suck the inside of the inner tank 11 of the cleaning tank 10 to a negative pressure. The cleaning liquid and air in the inner tank 11 drained or sucked by the ejector 50 are separated in the gas-liquid separation box 40, and the cleaning liquid falls into the box and is appropriately drained from the drain port. The air is separated in the gas-liquid separation box 40 and is appropriately exhausted from the exhaust port.

Each of the above-mentioned steps will be specifically described. In the immersion step S1, the valve V1 and the valve V2 are opened and the valve V3 is closed to form a cleaning liquid injection flow path, and the cleaning liquid supply unit 30 is operated (pressurized) to clean the cleaning liquid in the cleaning liquid tank 31. Is filled and injected into the inner tank 11 of the washing tank 10. Then, the ink ejection head H is moved to a standby position on the cleaning tank 10, and the nozzle surface Ha of the ink ejection head H is immersed in the injected cleaning liquid as shown in FIG. 3A. This immersion state is continued for a time suitable for the deposits on the nozzle surface Ha to swell or dissolve. During that time, the injection of the cleaning liquid into the inner tank 11 is continued, and the cleaning liquid in the inner tank 11 is poured onto the nozzle surface Ha and overflows into the outer tank 12. The cleaning liquid overflowing to the outer tank 12 is drained to the gas-liquid separation box 40 or the like through the flow path e at any time.

In the suction step S2, the valve V2 and the valve V3 are opened, the valve V1 is closed to form a drainage / suction flow path, and the ejector 50 is operated to drain the cleaning liquid in the inner tank 11 of the cleaning tank 10. Then, as shown in FIG. 3B, the front surface of the ink ejection head H is brought into contact with the sealing material 13 provided at the upper end of the inner tank 11, and the inside of the inner tank 11 of the cleaning tank 10 is sucked into a negative pressure state. do. As a result, the cleaning liquid adhering to the nozzle surface Ha and the one dissolved by the cleaning liquid are sucked and removed, and the nozzles in the ink ejection head H are unclogging.

In the maintenance before the printing operation, the liquid absorbing step S3 described later is performed after the suction step S2 described above, but during the standby after the series of printing operations are performed, the immersion step S1 and the suction step S2 described above are performed. Later, the inside of the inner tank 11 is filled with the cleaning liquid again, and the front surface of the ink ejection head H is made to stand by in contact with the sealing material 13 provided at the upper end of the inner tank 11. At this time, by bringing the front surface of the head H into contact with the sealing material 13, the inner tank 11 can be closed with the head H and the inside of the inner tank 11 can be sealed, and the cleaning liquid stored in the inner tank 11 can be sealed. Volatilization can be suppressed.

In the liquid absorbing step S3, the ink ejection head H is moved onto the liquid absorbing sheet unit 20 and the liquid absorbing sheet T is brought into contact with the nozzle surface Ha to absorb and remove the residual liquid on the nozzle surface Ha. At this time, it is required that the liquid absorbing sheet T does not rub the surface of the nozzle surface Ha.

FIG. 4 shows a configuration example of the liquid absorbing sheet unit 20. As shown in FIG. 4, the liquid absorbing sheet unit 20 supports a liquid absorbing sheet T having both ends wound on a roll on a support frame 21. The liquid absorbing sheet T is pulled out from the unused roll T'to the used roll T'in a loose state or under tension under the nozzle surface Ha, and the liquid absorbing sheet T is pulled out by the contact roll 22. A part of the sheet T is in linear contact with the nozzle surface Ha. The contact roll 22 moves in the direction of the arrow in the drawing with respect to the support frame 21, so that the contact position between the liquid absorbing sheet T and the nozzle surface Ha Will move, and the entire surface of the nozzle surface Ha will come into contact with the liquid absorbing sheet T. At this time, since the nozzle surface Ha and the liquid absorbing sheet T do not move relatively, the nozzle surface Ha is the liquid absorbing sheet T. It will not be rubbed.

In each liquid absorbing step in which the entire surface of the nozzle surface Ha comes into contact with the liquid absorbing sheet T, the used liquid absorbing sheet T is wound around the used roll T ”and is unused from the unused roll T ′. The liquid absorbing sheet T is sent out below the nozzle surface Ha. At this time, the nozzle surface Ha is separated from the liquid absorbing sheet T.

In the test shot step S4, the nozzle surface Ha of the ink ejection head H is moved to a standby position on the cleaning tank 10, and the ink ejection head H is used to test ink. By performing a trial shot on the cleaning tank 10, the ink ejected from the nozzle can be stored in the cleaning tank 10, and the surrounding contamination due to ink scattering can be prevented. In addition, a target for trial striking may be prepared separately, and trial striking may be performed toward the target.

In the trial striking step S4, it is desirable to confirm the flight of the ink. To confirm the flight of ink, the flight state of the ink ejected from the nozzle is photographed by a camera (for example, moving image is photographed), and whether or not the flight state is normal is confirmed. As an example, the camera used at this time can be a camera mounted on the head in order to control the operation of the ink ejection head, but the camera is not limited to this, and a camera fixed to the outside or the like can be used. You may use it. If it is confirmed that the flight state is not normal, the above-mentioned steps S1 to S4 are repeated to perform maintenance again, and if it is confirmed that the flight state is normal, the maintenance is completed and the next step is performed. Prepare for printing operation (track correction process, etc.).

As described above, according to the ink ejection head maintenance method and the maintenance apparatus according to the embodiment of the present invention, the nozzle surface of the ink ejection head is not damaged, the adverse effect on the ink flight is eliminated, and the nozzle is clogged. Deposits can be removed.

In particular, when performing omnidirectional inkjet printing, since the flying state of ink due to gravity differs in each direction, a correction step for correcting this is performed before the printing operation. By performing the maintenance method according to the form before the correction step, the effect of the correction can be enhanced, and a stable and accurate ink flight state can be maintained.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the design changes, etc. within the range not deviating from the gist of the present invention, etc. Even if there is, it is included in the present invention. Further, each of the above-described embodiments can be combined by diverting the techniques of each other as long as there is no particular contradiction or problem in the purpose and configuration thereof.

10: Cleaning tank, 11: Inner tank, 12: Outer tank, 13: Sealing material,
20: Liquid absorbing sheet unit, 21: Support frame, 22: Contact roll,
30: Cleaning liquid supply unit, 31: Cleaning liquid tank,
40: Gas-liquid separation box, 50: Ejector,
H: Ink ejection head, Ha: Nozzle surface, T: Liquid absorbing sheet, a to e: Flow path,
V1 to V3: Valve

Claims (7)

A dipping process in which the nozzle surface of the ink ejection head is immersed in the cleaning liquid injected into the cleaning tank, and
A suction step of draining the cleaning liquid from the cleaning tank and sucking the inside of the cleaning tank to suck and remove the cleaning liquid adhering to the nozzle surface and to unclog the nozzle in the ink ejection head.
A method for maintaining an ink ejection head, which comprises a liquid absorbing step of removing a residual liquid on the nozzle surface by bringing the liquid absorbing sheet into contact with the nozzle surface. The maintenance method for an ink ejection head according to claim 1, wherein the dipping step is performed by pouring the cleaning liquid injected into the cleaning tank onto the nozzle surface. After the liquid absorption step,
The maintenance method for an ink ejection head according to claim 1 or 2, wherein the nozzle surface is located on the cleaning tank, and the ink ejection head is used for trial printing of ink. It is a maintenance device for the ink ejection head.
Equipped with a cleaning tank in which the cleaning liquid that immerses the nozzle surface of the ink ejection head is injected.
The ink ejection head is characterized in that the cleaning tank is connected to a cleaning liquid injection flow path for injecting the cleaning liquid into the tank and a drainage / suction flow path for draining the cleaning liquid in the tank and sucking the cleaning liquid in the tank. Maintenance equipment. The ink ejection head according to claim 4, wherein the cleaning tank has a two-tank structure consisting of an inner tank into which the cleaning liquid is injected and an outer tank in which the cleaning liquid poured on the nozzle surface is received. Maintenance device. The maintenance device for an ink ejection head according to claim 4 or 5, wherein the drainage / suction flow path is connected to a gas-liquid separation box via an ejector. The maintenance device for an ink ejection head according to any one of claims 4 to 6, further comprising a liquid absorbing sheet unit that supports a liquid absorbing sheet that absorbs and removes residual liquid on the nozzle surface.

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