JP2008237952A - Method of manufacturing coated body and droplet spray coating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of defective quality of a coated body caused by the presence of remaining vibration of a meniscus by quickly attenuating the remaining vibration of the meniscus in liquid after spraying droplets. <P>SOLUTION: The method of manufacturing coated body comprises: a process of applying a first pulse voltage P1 to a piezoelectric element to change the volume of a liquid chamber in which the liquid is stored, and spraying a part of the liquid from a nozzle communicated with the liquid chamber as the droplets to be applied onto a coating object; and a process of applying a plurality of second pulse voltages P2 to the piezoelectric element to change the volume of the liquid chamber and continuously producing vibration of a phase opposite to the phase of the remaining vibration of the meniscus produced in the liquid in the liquid chamber after spraying the droplets to attenuate the remaining vibration of the meniscus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a coated body and a droplet spray coating apparatus, and more particularly to a method for manufacturing a coated body that attenuates meniscus residual vibration that occurs when droplets are ejected from a nozzle, and attenuates meniscus residual vibration. The present invention relates to a droplet spray coating apparatus having a function of causing

  Droplet ejection that displaces a piezoelectric element by applying a pulse voltage, ejects the liquid in the liquid chamber as a droplet from the nozzle using the displacement of the piezoelectric element, and applies the ejected liquid droplet to a coating object Application devices are known. The droplets ejected from the droplet spray coating apparatus fly in the form of water droplets composed of a head located on the tip side in the ejecting direction and a tail extending behind the head.

  In such a droplet spray coating apparatus, as described in Patent Document 1 below, a first pulse voltage having a large pulse width and a second pulse voltage having a small pulse width are applied to the piezoelectric element. The present invention is known.

According to the present invention, by applying the first pulse voltage to the piezoelectric element, a part of the liquid in the liquid chamber is ejected as a droplet from the orifice. By applying the second pulse voltage to the piezoelectric element, the tail part is well separated from the head part, the length of the generated tail part is shortened, and the length dimension of the ejected droplet is small. Become.
JP 2001-518030 A

  However, in the invention described in the above-mentioned special table 2001-518030, the following points are not considered.

  When a droplet is ejected by applying a pulse voltage to the piezoelectric element, residual meniscus vibration in which the meniscus on the liquid level of the nozzle vibrates occurs in the liquid after the droplet is ejected. If droplets are ejected continuously when meniscus residual vibration is generated in the liquid, the liquid volume “sparse” part and “dense” part appear in the flying liquid droplet due to the influence of the meniscus residual vibration. As a result, the presence / absence of “dense / dense” in the droplets causes a problem that the flying droplets are constricted in the “sparse” part and separated into two or more.

  When the droplets that should fly as one droplet fly in a state in which the droplets are separated into two or more, the droplets that have separated and flew are applied one after another on the object to be coated. For this reason, the shape of the applied droplet may be an elongated streak or ellipse, or may be applied separately at two or more locations.

  If the flying droplets are elongated, oval, or separated into two or more and applied to the application object, the application state of the droplets on the application object becomes poor, and the application object The quality of the coated body produced by applying droplets to an object varies.

  The present invention has been made to solve such a problem, and its purpose is to quickly attenuate the meniscus residual vibration in the liquid after ejecting the liquid droplets, and to cause the meniscus residual vibration to exist. Another object of the present invention is to provide an application body manufacturing method and a droplet spray coating apparatus capable of preventing the occurrence of poor quality of the applied body.

  A first feature according to an embodiment of the present invention is that, in the method of manufacturing an application body, the first pulse voltage is applied to the piezoelectric element to change the volume of the liquid chamber in which the liquid is stored, and a part of the liquid Spraying from a nozzle communicating with the liquid chamber as a droplet to be applied to an object to be applied, and applying a plurality of second pulse voltages to the piezoelectric element to vary the volume of the liquid chamber, And attenuating the meniscus residual vibration by continuously generating in the liquid a vibration having a phase opposite to that of the meniscus residual vibration generated in the liquid in the liquid chamber.

  According to a second aspect of the present invention, in the droplet spray coating apparatus, the liquid chamber storing the liquid, the nozzle communicating with the liquid chamber, the volume of the liquid chamber is varied, A piezoelectric element that ejects a part of the liquid as droplets from the nozzle, and a first pulse voltage and a second pulse voltage of the method for manufacturing a coated body according to any one of claims 1 to 3 are applied to the piezoelectric element. And a control unit.

  According to the present invention, the residual meniscus vibration in the liquid after ejecting the liquid droplets can be quickly damped, and the occurrence of poor quality of the coated body due to the presence of the residual meniscus vibration can be prevented. Can do.

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

  A liquid droplet spray coating apparatus according to an embodiment of the present invention ejects a liquid such as ink as liquid droplets, and applies liquid droplets that are ejected and flying to a coating object to provide a liquid crystal panel or the like as an application body. It is a device to manufacture. As shown in FIG. 1, the droplet spray coating apparatus 1 includes a droplet spray coating head 2 that is a portion that sprays droplets E, and a moving mechanism that moves the droplet spray coating head 2 to a droplet spray position. (Not shown) and a liquid supply mechanism (not shown) for supplying the liquid to the droplet jet coating head 2.

  The droplet spraying application head 2 includes a plurality of liquid chambers 3 in which liquid is stored, a liquid reservoir 4 communicating with each liquid chamber 3, and a nozzle plate 5 that forms a part of the wall of each liquid chamber 3. And a diaphragm 6 that forms another part of the wall of the liquid chamber 3, and a piezoelectric element 8 that is provided for each liquid chamber 3 and is fixed to the diaphragm 6 via an elastic material 7. .

  A plurality of nozzles 9 are formed on the nozzle plate 5, and each nozzle 9 communicates with each liquid chamber 3 one by one. From each nozzle 9, the liquid in each liquid chamber 3 is ejected as droplets E. Connected to the piezoelectric element 8 is a controller 10 that applies a pulse voltage to the piezoelectric element 8 to deform the piezoelectric element 8 in the expansion / contraction direction and controls the voltage value and timing of the applied pulse voltage. Yes.

  Examples of the pulse voltage applied to the piezoelectric element 8 under the control of the control unit 10 include a first pulse voltage P1 and a second pulse voltage P2. The first pulse voltage P1 is applied once every time one droplet E is ejected. The second pulse voltage P2 is continuously applied a plurality of times each time one droplet E is ejected.

  When the first pulse voltage P1 is applied to the piezoelectric element 8, the piezoelectric element 8 is deformed in a contracting direction, and the diaphragm 6 is bent to a position indicated by a solid line in FIG. 1 to increase the volume of the liquid chamber 3. As a result, the liquid on the nozzle 9 side in the liquid chamber 3 is sucked into the diaphragm 6 side as indicated by an arrow A, and the liquid in the liquid reservoir 4 is sucked into the liquid chamber 3 as indicated by an arrow B. Is done. Thereafter, when the application of the first pulse voltage P1 is completed, the piezoelectric element 8 and the diaphragm 6 are returned to the positions indicated by the broken lines in FIG. 1, and the volume in the liquid chamber 3 is reduced. Thereby, a part of the liquid in the liquid chamber 3 is ejected as a droplet E from the nozzle 9, and the droplet E ejected from the nozzle 9 is applied to the application object 11 disposed at a position facing the nozzle 9. The In addition, after the droplet E is ejected from the nozzle 9, a meniscus residual vibration in which the meniscus on the liquid surface of the nozzle 9 vibrates is generated in the liquid in the liquid chamber 3.

  By applying the second pulse voltage P <b> 2 to the piezoelectric element 8, a vibration having a phase opposite to the meniscus residual vibration generated in the liquid in the liquid chamber 3 after the ejection of the droplet E from the nozzle 9 is generated in the liquid chamber 3. Occurs in liquids.

  Since the meniscus residual vibration is a free vibration having a natural frequency determined by the geometric shape of the liquid chamber 3, the viscosity of the liquid, and the like, the generation timing can be predicted. Therefore, it is also possible to predict the timing of applying a plurality of second pulse voltages P2 that generate vibrations in phase opposite to the meniscus residual vibration. The second pulse voltage P2 is applied at a timing that is in reverse phase to the predicted meniscus residual vibration.

  FIG. 2 shows the first pulse voltage P1 and a plurality of second pulse voltages P2. 2A, 2 </ b> B, and 2 </ b> C, the first pulse voltage P <b> 1 is applied to the piezoelectric element 8, whereby a part of the liquid in the liquid chamber 3 is changed to the droplet E. And is ejected from the nozzle 9. Regarding the plurality of second pulse voltages P2 applied after the droplet E is ejected from the nozzle 9, the voltage value and the pulse width may be the same as shown in FIG. As shown in FIG. 2 (b), the voltage value may be made smaller by making the pulse width the same, or by making the voltage value the same and making the pulse width gradually made smaller as shown in FIG. 2 (c). Also good.

  The voltage value and pulse width of the second pulse voltage P2 shown in FIGS. 2A, 2B, and 2C are the same as those of the droplet E from the nozzle 9 when the second pulse voltage P2 is applied. The value is set so that injection is not performed.

  The timing of applying the second pulse voltage P2, and the voltage value and pulse width reduction of the second pulse voltage P2 are controlled by the control unit 10 according to a preset algorithm.

  In such a configuration, after the droplet E is ejected from the nozzle 9, a meniscus residual vibration in which the meniscus on the liquid surface of the nozzle 9 vibrates occurs in the liquid in the liquid chamber 3. Therefore, by applying a plurality of second pulse voltages P <b> 2 to the piezoelectric element 8 and generating a vibration in the opposite phase to the meniscus residual vibration in the liquid in the liquid chamber 3, the meniscus residual vibration can be quickly attenuated. .

  For this reason, even when the droplets E are continuously ejected at short intervals, each droplet E is not affected by the residual meniscus vibration, and the flying droplet E is affected by the residual meniscus vibration. Therefore, it does not occur that it is separated into two or more. Then, the flying droplet E can be applied to the target application position on the application object 11 with high accuracy, and the quality of the application body manufactured by applying the droplet E to the application object 11. Can be made uniform and high quality can be achieved.

  The meniscus residual vibration is attenuated as the second pulse voltage P2 is applied. Therefore, according to the attenuation of the meniscus residual vibration, the meniscus residual vibration can be efficiently damped by gradually reducing the voltage values of the plurality of second pulse voltages P2 to be applied as shown in FIG. it can. Alternatively, the meniscus residual vibration can be efficiently damped by gradually reducing the pulse width of the applied plurality of second pulse voltages P2 as shown in FIG. 2 (c) in accordance with the attenuation of the meniscus residual vibration. . Further, the voltage values of the plurality of second pulse voltages P2 to be applied are gradually reduced as shown in FIG. 2B, or the pulse widths of the plurality of second pulse voltages P2 to be applied are shown in FIG. As shown in FIG. 5, the power consumed to apply the second pulse voltage P2 can be reduced by gradually reducing the voltage.

1 is a schematic diagram illustrating a droplet spray coating apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the pulse waveform of a 1st pulse voltage and a 2nd pulse voltage.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Liquid chamber, 8 ... Piezoelectric element, 9 ... Nozzle, 10 ... Control part, 11 ... Application | coating object, E ... Droplet, P1 ... 1st pulse voltage, P2 ... 2nd pulse voltage

Claims (4)

A first pulse voltage is applied to the piezoelectric element to vary the volume of the liquid chamber in which the liquid is stored, and a part of the liquid is ejected from a nozzle communicating with the liquid chamber as a droplet applied to the application target. Steps,
A plurality of second pulse voltages are applied to the piezoelectric element to vary the volume of the liquid chamber, and a vibration in the phase opposite to the meniscus residual vibration generated in the liquid in the liquid chamber after ejection of the liquid droplets is generated in the liquid. Dampening the meniscus residual vibration by continuously generating
The manufacturing method of the application body characterized by the above-mentioned.   The method of manufacturing an application body according to claim 1, wherein voltage values of the plurality of second pulse voltages are gradually reduced.   2. The method of manufacturing an application body according to claim 1, wherein pulse widths of the plurality of second pulse voltages are gradually reduced. A liquid chamber in which liquid is stored;
A nozzle communicating with the liquid chamber;
A piezoelectric element that varies the volume of the liquid chamber and ejects a part of the liquid as droplets from the nozzle;
A control unit that applies the first pulse voltage and the second pulse voltage of the manufacturing method of the application body according to any one of claims 1 to 3 to the piezoelectric element;
A droplet spray coating apparatus comprising:

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