JP2009269336A - Liquid droplet ejection method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable ejection of a liquid droplet material even if the consumption of the liquid droplet material is reduced. <P>SOLUTION: In the case that a head 1 having a nozzle 2 for discharging a liquid droplet is stopped for discharging for a long period of time in order to seal the surface of the head 1 having the nozzle 2 from the outside atmosphere, a plate cap 4 is contacted and pressed to the head 1 so that stable liquid droplet ejection is enabled by press-adhhering the nozxle 2 even if the solution is not sucked like a prior art. Alternatively, the plate cap 4 is made to contact with and pressed to the head 1 after a plate cap is immersed in the liquid droplet material or a solvent for creating the liquid droplet material before the plate cap 4 is made to contact with and pressed to the head 1. Thereby, close contact reliability is further improved, the consumption of the liquid droplet material is reduced and the stable ejection of the liquid droplet material can be performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet ejection method and apparatus for stabilizing droplet ejection, and is particularly applied to an inkjet droplet ejection apparatus.

  2. Description of the Related Art Conventionally, an ink jet method has been used in a manufacturing process of a display for a consumer printer, an industrial printing device, or an electro-optical device. The ink jet method is used as a technique for depositing a material on an object, and is a method for discharging a liquid material from a nozzle provided in an ejection head, which is more liquid than other coating techniques such as a spin coat method. There is an advantage that the material can be used and the patterning can be applied directly and accurately on the object with less wasteful consumption of material.

  Furthermore, in the inkjet method, application to various product fields is expected by using a special material such as a special ink or a photosensitive resin as a liquid material.

  In a droplet discharge device such as an ink jet printer, a material obtained by dissolving a solute with a solvent is generally used as a droplet material. For this reason, when the operation is stopped, the solvent evaporates over time, and the viscosity of the droplet material on the droplet discharge surface of the inkjet head increases.

When the viscosity of the droplet material in the droplet discharge hole on the ink jet head surface increases, the droplet discharge nozzle becomes clogged, causing non-discharge or unstable discharge. Therefore, conventionally, a method of using a head cap to cover the head surface and suck the droplet material has been performed.
JP-A-47-30337 JP 2004-142422 A

  By the way, when the cap for preventing clogging of the discharge head described in Patent Documents 1 and 2 is used, it is a method of sucking the droplet material. In the case of expensive droplet material, there is a problem that the cost becomes high. For example, depending on the usage, it may be necessary to suction several tens of cc per time with one head. In particular, if the discharge stops frequently, the number of times of suction increases, and a large amount of droplet material is consumed.

  For this reason, it is conceivable to reduce the suction amount, but when the head is stopped for a long time, the cap is not in direct contact with the nozzle hole of the head. Increases viscosity. Therefore, there is a problem that clogging is not improved and non-ejection or unstable ejection occurs.

  In addition, due to the chemical nature of the solvent of the droplet material, there is a problem that normal rubber-based resins swell and cannot be sucked. Depending on the type of solvent, there are almost no solvent-resistant materials at present, and some of the solvent-resistant materials are difficult to mold with a mold or the like, and in that case, must be machined. For this reason, there exists a problem that manufacturing cost becomes high when making it annular shape.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a droplet discharge method and apparatus that can realize stable discharge of a droplet material even if consumption of the droplet material is reduced.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a droplet ejection method for ejecting droplets using a head having a nozzle for ejecting droplets, wherein the droplet ejection from the nozzles is stopped. The member is pressure-bonded to the surface on which the nozzle is formed in order to block the surface on which the nozzle is formed from the external atmosphere.

  According to a second aspect of the present invention, in the droplet discharge method according to the first aspect of the present invention, after the member is immersed in a droplet material or a solvent that generates the droplet material, the member is pressure-bonded to the head.

  According to a third aspect of the present invention, in the droplet discharge method according to the first or second aspect, the member is brought into elastic contact with the head.

According to a fourth aspect of the present invention, in the droplet discharge method according to any one of the first to third aspects, the member is pressure-bonded to the head at a pressure of 15 to 80 gf / cm ² .

  According to a fifth aspect of the present invention, in the droplet discharge method according to the first aspect, the displacement of the head is measured, the measured displacement is compared with a preset reference displacement, and the member is brought into close contact with the head. It is characterized by determining whether or not.

  According to a sixth aspect of the present invention, in the droplet discharge device, a head having a nozzle for discharging a droplet, and a surface having the nozzle in the head when the droplet discharge of the nozzle is stopped for a long time And a member that is pressure-bonded to the head in order to cut off from the external atmosphere.

  According to a seventh aspect of the present invention, in the droplet discharge device according to the sixth aspect, the container is provided with a droplet material that immerses the member or a solvent that generates the droplet material before the member is pressure-bonded to the head. It is characterized by that.

  According to an eighth aspect of the present invention, in the liquid droplet ejection apparatus according to the sixth or seventh aspect, the apparatus includes a plurality of elastic members for pressing the member to the head.

According to a ninth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the sixth to eighth aspects, the pressure of the member that is in pressure contact with the head is set to 15 to 80 gf / cm ² .

  According to a tenth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the sixth to ninth aspects, the shape of the member is a plate.

  The invention according to claim 11 is the droplet discharge device according to any one of claims 6 to 9, wherein the member is formed of a tube.

  According to a twelfth aspect of the present invention, in the liquid droplet ejection device according to any one of the sixth to eleventh aspects, a resin material having corrosion resistance to the liquid material to be ejected is used as a material of the member. Features.

  According to a thirteenth aspect of the present invention, in the droplet discharge device according to the sixth aspect, in order to check whether or not the member is in close contact with the head, the displacement of the piezoelectric element incorporated in the head is measured. And a means for controlling the compression by comparing the measured displacement with a preset reference displacement.

  According to the present invention, even when the operation is stopped for a long time, stable discharge of the droplet material can be realized without consuming the droplet material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a configuration of an inkjet head and a cap in a droplet discharge device for explaining Embodiment 1 of the present invention.

  As shown in FIG. 1, the head 1 is provided with a plurality of nozzles 2 for discharging droplets. A plate-like cap 4 made of a solvent-resistant material is placed and fixed on a pressure contacting table 3 made of stainless steel. The press contact table 3 is supported by a press contact plate 6 by a support column 5 made of stainless steel so as to be movable up and down, and is urged toward the head 1 by a spring 7 which is an elastic member. The pressure contact plate 6 that supports the column 5 is rotatably installed. Further, as will be described later, in order not to dry the plate-like cap 4, a container 9 filled with a droplet material or a solvent 8 for generating the droplet material is provided along with the head 1.

The solvent 8 is automatically supplied by a supply device (not shown). In this example, methoxytoluene (CH ₃ OC ₆ H ₄ CH ₃ ) having a boiling point of 175 ° C. was used as the solvent 8. Kalrez (registered trademark, manufactured by DuPont), which is a fluorine-based material, was used for the plate-like cap 4 as a solvent-resistant material.

  Next, the operation in the first embodiment will be described. In FIG. 1, the discharge position is a position for discharging a droplet, and the stop position is a position where the droplet discharge is stopped for a long time.

  When the droplet discharge is stopped for a long time, the head 1 that stopped the droplet discharge moves from the discharge position to the stop position. After moving to the stop position, the pressure contact plate 6 is driven to rotate, whereby the plate-like cap 4 is inverted and lowered to be immersed in the solvent 8 in the container 9. FIG. 2 shows a state where the plate cap 4 is immersed in the solvent 8.

  When the plate-like cap 4 is immersed in the solvent 8, the plate-like cap 4 pressurizes the head 1 by driving the pressure-contact plate 6 in the reverse direction to face the head 1 and ascend. At this time, since the spring 7 urges the plate-like cap 4 through the press contact table 3 at two locations, the plate-like cap 4 pressurizes the nozzles 2 of the head 1 evenly. The surface of the nozzle 2 of the head 1 is subjected to water repellent treatment in order to stably discharge droplets. Since the water-repellent surface (not shown) is uniformly pressed by the plate-like cap 4, the water-repellent surface near the nozzle 2 of the head 1 is not damaged, and thus stable discharge is possible during discharge. It becomes.

In this example, the pressure applied to the nozzle 2 surface of the head 1 was equivalent to a pressure of 25 gf / cm ² . Actually, the experimental results show that the plate cap 4 is in close contact unless it is less than 15 gf / cm ² . The upper limit of the pressure is considered to be an appropriate value of 80 gf / cm ² or less at which the nozzle hole shape does not remain in the plate-like cap 4 after pressurization. If the shape of the nozzle hole remains in the plate-like cap 4 after pressurization, the close contact is complete and the reliability is improved. However, considering the frequency of repeated use, the frequency of replacement as a consumable increases and the cost increases. is there.

  As described above, the stable discharge was evaluated in a state where the nozzle 2 of the head 1 was completely shut off from the outside air by the plate-shaped cap 4. Even when ejected at a discharge cycle of 30 kHz after moving from 1 to the discharge position, stable droplet discharge could be obtained.

  As described above, by completely contacting the nozzle 2 of the head 1 with the plate-like cap 4, stable droplet discharge can be realized without sucking droplets as in the prior art. Consumption can also be reduced. In addition, since the cap shape is a plate shape, an inexpensive device can be obtained.

(Embodiment 2)
FIG. 3 is a cross-sectional view showing a configuration of an inkjet head and a cap in a droplet discharge device for explaining Embodiment 2 of the present invention.

  FIG. 3 is a cross-sectional view of the head 11 as viewed from the short side. The configuration of the head 11 is the same as that of the first embodiment, and a plurality of nozzles 12 for discharging droplets are provided. A tube 14 made of a solvent-resistant material is placed and fixed on a pressure contact table 13 made of stainless steel. The press contact table 13 is supported by the press contact plate 16 and has a function of a container for storing the solvent 15 for generating the droplet material. The solvent 15 is automatically supplied by a supply device (not shown).

Methoxytoluene (CH ₃ OC ₆ H ₄ CH ₃ ) having a boiling point of 175 ° C. was used as the solvent 15. The tube 14 is a fluorine material tube as a solvent resistant material. A normal rubber-based tube swells, and a result that a fluorine-based material is good is obtained. The pressure plate 16 has a pressure mechanism and pressurizes the pressure table 13.

  FIG. 4 is a cross-sectional view of the head 11 as seen from the side surface on the long side. A rotating shaft 17 for rotating the tube 14 is inserted and fixed in a hole at one end of the tube 14. Air is supplied to the tube 14 on the side opposite to the installation side of the rotary shaft 17 by an air supply device (not shown). A resin material (silicon) was used for the rotating shaft 17. The rotary shaft 17 is rotationally driven by the rotary drive device 18, and the rotary shaft 17 is rotated only in half rotation. For example, when the rotary shaft 17 is rotated halfway in the clockwise direction, the next rotation is rotated counterclockwise by half.

  Next, the operation in the second embodiment will be described. In FIG. 3, the discharge position is a position for discharging a droplet, and the stop position is a position where the droplet discharge is stopped for a long time.

  When the droplet discharge is stopped for a long time, the head 11 which stopped the droplet discharge moves from the discharge position to the stop position. After moving to the stop position, the tube 14 is driven half-turn, the surface immersed in the solvent 15 faces in the direction of the head 11 surface, and air is supplied to the tube 14.

  The pressure plate 16 rises and presses the pressure table 13 toward the head 11, and indirectly presses the head 11 through the tube 14. In order to pressurize with the tube 14, the nozzle 12 of the head 11 is pressurized uniformly. The surface of the nozzle 12 of the head 11 is subjected to water repellent treatment in order to stably discharge droplets. By evenly pressurizing the water repellent surface (not shown), the water repellent surface near the nozzle 12 of the head 11 is not damaged, and thus stable discharge is possible even after long-term use. Become.

In this example, the pressure applied to the head was applied to the surface of the head 11 so as to correspond to a pressure of 20 gf / cm ² .

  As described above, the stable discharge was evaluated in a state where the nozzle 12 of the head 11 was completely blocked from the outside air by the tube 14, and as a result, the tube 14 was separated from the head 11 again after stopping for 72 hours in a close contact state. Stable droplet ejection could be obtained even when ejection was performed at a 30 kHz ejection cycle after moving to the ejection position.

  As described above, when the nozzle 12 of the head 11 is completely brought into close contact with the tube 14, stable droplet discharge can be realized without sucking droplets as in the conventional case. Therefore, wasteful consumption of droplets can be suppressed. Moreover, since the cap shape is a tube, an inexpensive device can be obtained.

(Embodiment 3)
FIG. 5 is a schematic configuration diagram of a droplet discharge device for explaining the third embodiment of the present invention. The third embodiment is basically an inkjet head and cap having the same configuration as that of the first embodiment. It is a system that measures and evaluates whether or not the inkjet head and the cap are completely in close contact with each other.

  As shown in FIG. 5, as described in the first embodiment, the head 1 is provided with a plurality of nozzles 2 for discharging droplets. A plate-like cap 4 made of a solvent-resistant material is placed and fixed on a pressure contacting table 3 made of stainless steel. The press contact table 3 is supported by a support column 5 made of stainless steel so as to be movable up and down with respect to the press contact plate 6, and is pressed toward the head 1 by a spring 7 which is an elastic member. The pressure contact plate 6 that supports the column 5 is rotatably installed. Further, as will be described later, in order not to dry the plate-like cap 4, a container 9 filled with a droplet material or a solvent 8 for generating the droplet material is provided along with the head 1.

The solvent 8 is automatically supplied by a supply device (not shown). In this example, methoxytoluene (CH ₃ OC ₆ H ₄ CH ₃ ) having a boiling point of 175 ° C. was used as the solvent 8. The plate-like cap 4 uses Kalrez (registered trademark: DuPont), which is a fluorine-based material, as a solvent-resistant material.

  In the third embodiment, the head 1 is provided with a piezoelectric element 21 that is a mechanism for discharging droplets. The piezoelectric element 21 vibrates by application of a voltage, the vibration is transmitted to the diaphragm 22, and a droplet is ejected from the nozzle 2 by the movement of the diaphragm 22.

  Further, a laser light emitting / receiving device 23 is installed at the installation portion of the piezoelectric element 21, and the laser emitting / receiving device 23 irradiates the piezoelectric element 21 in the head 1 with light and receives reflected light from the piezoelectric element 21. To do. Further, the displacement of the piezoelectric element 21 is measured by the Doppler displacement measuring device 24. A signal from the Doppler displacement measuring device 24 is sent to the oscilloscope 25. The oscilloscope 25 also receives a timing signal of a signal for driving the piezoelectric element 21, and can represent an actual driving waveform of the piezoelectric element 21 from the driving timing signal and the displacement signal of the piezoelectric element 21. Then, the data processor 26 evaluates the difference between the waveform actually obtained from the displacement of the piezoelectric element 21 and the drive waveform input to the piezoelectric element 21.

  FIG. 6A is a diagram showing a driving waveform obtained from the displacement of the piezoelectric element 21 when a droplet is ejected from the head 1, and FIG. 6B is a diagram showing a droplet in which the plate cap 4 is in close contact with the head 1. It is a figure which shows the drive waveform calculated | required from the displacement of the piezoelectric element 21 when not discharging.

  When discharging, a steep vibration is observed in the waveform as shown in FIG. 6A, but when a droplet is not discharged, as shown in FIG. 21 has the same shape as the drive waveform of the voltage input to 21 and no vibration is observed.

  Next, the operation in the third embodiment will be described.

  When the droplet discharge is stopped for a long time, the head 1 that stopped the droplet discharge moves from the discharge position to the stop position. After moving to the stop position, the pressure contact plate 6 is driven to rotate, whereby the plate-like cap 4 is inverted and lowered to be immersed in the solvent 8 in the container 9.

When the plate-like cap 4 is immersed in the solvent 8, the plate-like cap 4 pressurizes the head 1 by driving the pressure-contact plate 6 in the reverse direction to face the head 1 and ascend. At this time, since the spring 7 urges the plate-like cap 4 through the press contact table 3 at two locations, the plate-like cap 4 pressurizes the nozzles 2 of the head 1 evenly. The surface of the nozzle 2 of the head 1 is subjected to water repellent treatment in order to stably discharge droplets. When the plate-like cap 4 pressurizes the water repellent surface (not shown) evenly, the water repellent surface near the nozzle 2 of the head 1 is not damaged, and stable discharge is possible during discharge. . The pressure applied to the nozzle 2 surface of the head 1 was equivalent to a pressure of 25 gf / cm ² .

  At the stage where the plate-like cap 4 is pressure-bonded to the head 1, the laser light emitting / receiving light emitting device 23 irradiates the piezoelectric element 21 in the head 1 with laser light and receives the reflected light, and the Doppler displacement measuring device 24 uses the piezoelectric element. 21 is measured, and a displacement signal is input to the oscilloscope 25. At the same time, a drive waveform signal for driving the actual piezoelectric element 21 input from the discharge waveform generation device (not shown) and the discharge waveform amplifier (not shown) is also input to the oscilloscope 25.

  Then, the respective signals of the drive waveform indicating the displacement of the drive waveform and the actually input drive waveform are input to the data processing device 26, and the plate-like cap 4 is securely attached based on the difference between the two drive waveforms. Judge whether or not. When it is determined that the contact is not complete, the pressurizing operation is performed again, and the driving waveform is observed in the data processing device 26 in the same manner. Crimping control is repeated until it is determined that this is completely adhered. Alternatively, when it is determined that the contact is not complete, a warning buzzer (not shown) or the like is notified.

  As described above, the displacement of the piezoelectric element 21 in the head 1 is measured, and the displacement waveform is compared with the reference waveform (reference displacement) when the plate-like cap 4 is completely in close contact with the head 1. Thus, it is possible to determine whether or not the contact is complete, and it is possible to obtain more reliable and stable droplet discharge. As a result, it is possible to realize stable droplet discharge without sucking droplets as in the prior art, so that wasteful consumption of droplets can be suppressed.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said Embodiment 1-3, A various change is possible.

  For example, the heads 1 and 11 have been shown as an example with a single head in the above embodiment, but even when a plurality of heads are arranged side by side, they are individually crimped by the plate cap 4 and the tube 14, respectively. A similar effect can be obtained.

  In order to improve the reliability of complete adhesion, the plate-like cap 4 and the tube 14 are immersed in the solvents 8 and 15 and then completely adhered to the heads 1 and 14. It is not always necessary to immerse in the solvents 8 and 15.

  Further, Kalrez (registered trademark) is used as the material of the plate-shaped cap 4 and a fluorine-based tube is used as the material of the tube 14. However, any other material having solvent resistance such as silicon can be used. it can.

  In order to pressurize the plate-shaped cap 4, the example which pressurized with the two springs 7 was shown, However, If it pressurizes with many springs, it can press more uniformly.

  In the second embodiment, in order to uniformly pressurize the nozzle 12 surface of the head 11, an example is shown in which air is supplied to the tube 14 to pressurize it. However, even if air is not supplied, depending on the structure of the tube 14. The same adhesion can be ensured only by its elasticity.

  The present invention is not limited to the application of a solution using an organic solvent, not only for consumer and industrial printing, but particularly for the application of droplets used in the manufacturing process of displays and semiconductors using high-performance and expensive ink. It can be used as an inkjet head.

Sectional drawing which shows the structure of the inkjet head and cap in the droplet discharge apparatus for describing Embodiment 1 of this invention The figure which shows the state which immersed the plate-shaped cap in the solvent in Embodiment 1. Sectional drawing which shows the structure of the inkjet head and cap in the droplet discharge apparatus for describing Embodiment 2 of this invention Sectional drawing which looked at the head from the side surface of the longitudinal side in Embodiment 2 Schematic configuration diagram of a droplet discharge device for explaining Embodiment 3 of the present invention (A) is a figure which shows the drive waveform calculated | required from the displacement of a piezoelectric element in case Embodiment 3 discharges the droplet from a head, (b) is a plate-shaped cap contact | adhered to a head, and a droplet discharges. Diagram showing drive waveform obtained from displacement of piezoelectric element when not

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Head 2,12 Nozzle 3,13 Pressure-contact base 4 Plate-shaped cap 5 Support | pillar 6,16 Pressure-contact plate 7 Spring 8,15 Solvent 9 Container 14 Tube 21 Piezoelectric element 22 Vibrating plate 23 Laser receiving and emitting device 24 Doppler displacement measuring device 26 Data processing device

Claims (13)

  In a droplet discharge method for discharging droplets using a head having a nozzle for discharging droplets, a member for blocking the surface on which the nozzles are formed from an external atmosphere when stopping droplet discharge from the nozzles A droplet discharge method, wherein the nozzle is pressure-bonded to a surface on which the nozzle is formed.   The droplet discharge method according to claim 1, wherein the member is pressed against the head after the member is immersed in a droplet material or a solvent that generates the droplet material.   The droplet discharging method according to claim 1, wherein the member is brought into elastic contact with the head. The droplet discharge method according to claim 1, wherein the member is pressure-bonded to the head at a pressure of 15 to 80 gf / cm ² .   The displacement of the head is measured, and the measured displacement is compared with a preset reference displacement to determine whether or not the member is in close contact with the head. Droplet ejection method.   A head having a nozzle for ejecting liquid droplets, and a member that presses against the head in order to shield the surface of the head having the nozzle from the external atmosphere when the liquid droplet ejection of the nozzle is stopped for a long time; A droplet discharge apparatus comprising:   7. The droplet discharge device according to claim 6, further comprising a container for storing a droplet material for dipping the member or a solvent for generating the droplet material before the member is pressure-bonded to the head.   8. The droplet discharge device according to claim 6, further comprising a plurality of elastic members for pressing the member against the head. 9. The droplet discharge device according to claim 6, wherein the pressure of the member pressed against the head is set to 15 to 80 gf / cm ² .   The droplet discharge device according to claim 6, wherein the member has a plate shape.   The droplet discharge device according to claim 6, wherein the member is constituted by a tube.   The droplet discharge device according to any one of claims 6 to 11, wherein a resin material having a corrosion resistance against a liquid material to be discharged is used as a material of the member.   In order to check whether or not the member is in close contact with the head, a means for measuring the displacement of the piezoelectric element incorporated in the head, and comparing the measured displacement with a preset reference displacement 7. A droplet discharge device according to claim 6, further comprising means for controlling pressure bonding.

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