JP2013199069A - Liquid ejection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejection device having stability in liquid ejection.SOLUTION: A liquid ejection device includes: an ejection head having a pressure chamber communicating with a nozzle and a pressure generating part for generating a pressure variation in a functioning liquid in a pressure chamber; and a control part that generates a driving signal including a micro vibration pulse to a degree where liquid droplets are ejected from the nozzle and drives the pressure generating part based on the driving signal. In the control part, the micro vibration pulse including a stirring vibration pulse for stirring the functional liquid and a heating vibration pulse for heating the functional liquid are generated.

Description

  The present invention relates to a droplet discharge device.

  Conventionally, when a liquid material such as liquid crystal is ejected, a voltage of a predetermined frequency is applied to the piezoelectric element of the ejection head to cause the liquid crystal to vibrate so as not to be ejected. A method of adjusting to an appropriate viscosity is known (for example, see Patent Document 1).

JP 2005-121736 A

  However, in the above method, the fine vibration waveform for heating the discharged functional liquid is remarkably short with respect to the natural vibration period of the functional liquid in the pressure chamber, so the functional liquid cannot follow the movement of the piezo element, Stirring of the functional fluid does not occur. As a result, the viscosity of the functional liquid at the nozzle opening increases, and there is a problem that the discharge state becomes unstable.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A droplet discharge apparatus according to this application example includes a discharge head having a pressure chamber communicating with a nozzle, a pressure generating unit that causes a pressure variation in the functional liquid in the pressure chamber, and liquid from the nozzle. A control signal that generates a drive signal including micro-vibration pulses that do not eject droplets, and that drives the pressure generator based on the drive signal. The control unit agitates the functional liquid. The fine vibration pulse including a stirring vibration pulse and a heating vibration pulse for heating the functional liquid is generated.

  According to this configuration, when the vibration pulse for stirring of the fine vibration pulse is applied to the pressure generating unit, the functional liquid of the ejection head is stirred. Thereby, an increase in viscosity can be suppressed. Further, when the vibration pulse for heating of the fine vibration pulse is applied to the pressure generating unit, the functional liquid of the ejection head is heated. Thereby, the viscosity of a functional liquid falls and it can be set as an appropriate viscosity. Thus, by applying the fine vibration pulse including the stirring vibration pulse and the heating vibration pulse, the ejection stability can be achieved.

  Application Example 2 In the control unit of the droplet discharge device according to the application example, the stirring vibration pulse is an expansion element that expands the pressure chamber or a contraction element that contracts the pressure chamber. It is characterized in that at least a part of the heating vibration pulse is included.

  According to this configuration, the length of the fine vibration waveform can be shortened. As a result, high-frequency ejection becomes possible and productivity can be improved.

  Application Example 3 In the control unit of the droplet discharge device according to the application example described above, each of the time from the start end to the end of the expansion element and the time from the start end to the end of the contraction element in the stirring vibration pulse is calculated. Further, it is set to be 1/2 or more of the natural vibration period Tc of the functional liquid in the pressure chamber.

  According to this configuration, the functional liquid can be efficiently stirred.

  Application Example 4 In the control unit of the droplet discharge device according to the application example, the time from the start end to the end of the expansion element or the time from the start end to the end of the contraction element in the heating vibration pulse It is characterized by being set to 1/2 or less of the natural vibration period Tc of the functional fluid in the pressure chamber.

  According to this configuration, the functional liquid can be efficiently heated.

The schematic diagram which shows the structure of a droplet discharge apparatus. Sectional drawing which shows the structure of an ejection head. The wave form diagram which shows the structure of a drive signal. The wave form diagram which shows the structure of the fine vibration pulse concerning a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is shown different from the actual scale so that each layer and each member can be recognized.

  First, the configuration of the droplet discharge device will be described. The droplet discharge device according to the present embodiment includes a discharge head having a pressure chamber communicating with a nozzle, a pressure generating unit that causes pressure fluctuations in the functional liquid in the pressure chamber, and a droplet that does not discharge droplets from the discharge head. A control unit that generates a drive signal including a vibration pulse and drives a pressure generation unit based on the drive signal, and the control unit heats the functional liquid with stirring vibration pulses for stirring the functional liquid. The fine vibration pulse including the vibration pulse for use is generated. This will be specifically described below.

  FIG. 1 is a schematic diagram illustrating a configuration of a droplet discharge device. As shown in FIG. 1, the droplet discharge device 1 includes a head unit 2, an X scanning axis 28 that serves as a guide axis for scanning the head unit 2 in the X axis direction, a stage 40 on which a workpiece W is placed, a stage A Y scanning axis (not shown) or the like serving as a guide axis for scanning 40 in the Y axis direction is provided. In the present embodiment, ultraviolet irradiation units 21 and 22 that irradiate ultraviolet rays are provided. And the control part (not shown) which controls the said member etc. is provided. The workpiece W is not particularly limited. For example, in addition to a plastic film, woven fabric (fabric) such as cotton cloth, linen cloth, silk cloth, paper, etc., and electronic parts such as a semiconductor device and an IC chip can be applied. .

  The head unit 2 includes a moving unit that moves on the X scanning axis 28, and the stage 40 includes a moving unit that moves on the Y scanning axis. The head unit 2 includes a carriage 10 connected to the X scanning shaft 28 and an ejection head 12 mounted on the carriage 10.

  The ultraviolet irradiation units 21 and 22 include an ultraviolet light source, and the ultraviolet light is irradiated from the ultraviolet light source. The ultraviolet light source can be appropriately applied, for example, an LED, a high-pressure mercury lamp, a metal halide lamp, or the like.

  Next, the configuration of the ejection head will be described. FIG. 2 is a cross-sectional view showing the configuration of the ejection head. As shown in FIG. 2, the ejection head 12 includes a nozzle plate 30 having nozzles 31. A flow path forming substrate 39 in which a flow path of the functional liquid 33 is formed is disposed on one surface of the nozzle plate 30 and bonded to the nozzle plate 30. A pressure chamber 32 communicating with the nozzle 31 is formed on the flow path forming substrate 39 at a position facing the nozzle 31.

  On the upper side of the pressure chamber 32, there are a vibration plate 34 that vibrates in the vertical direction (Z direction) and expands and contracts the volume in the pressure chamber 32, and a pressure generator that expands and contracts in the vertical direction to vibrate the vibration plate 34. The piezoelectric element 35 is provided.

  In addition to the piezoelectric element 35, as a pressure generating unit, a so-called electrostatic actuator that generates static electricity between the diaphragm and the electrode, deforms the diaphragm by electrostatic force, and discharges droplets from the nozzle, etc. May be used. Furthermore, the discharge head which has the structure which generates a bubble in a nozzle using a heat generating body, and discharges a functional liquid as a droplet with the bubble may be sufficient.

  The control unit includes a function of generating a drive signal for driving the piezoelectric element 35. In the control unit in the present embodiment, a discharge pulse for discharging the functional liquid 33 from the nozzle 31 as a droplet 36, a minute vibration pulse that does not discharge the droplet 36 from the nozzle 31, and the like are recorded in one recording cycle (one discharge cycle). ) Is generated. In the control unit of the present embodiment, a fine vibration pulse including a stirring vibration pulse for stirring the functional liquid 33 exposed in the opening of the nozzle 31 and a heating pulse for heating the functional liquid 33 is generated. The generated drive signal is output to the ejection head 12, and the ejection head 12 is configured to drive the piezoelectric element 35 based on the drive signal. Hereinafter, the configuration of the drive signal will be described.

  FIG. 3 is an explanatory diagram illustrating the configuration of the drive signal, FIG. 3A illustrates the configuration of the ejection pulse included in the drive signal, and FIG. 3B illustrates the fine vibration pulse included in the drive signal. The configuration is shown, and FIG. 3C shows the detailed configuration of the micro-vibration pulse. As shown in FIG. 3A, the ejection pulse DP1 has a substantially trapezoidal waveform shape, and a first expansion element PE1 that increases the potential with a predetermined gradient from the reference potential VB to the first potential Vh1, A first hold element PE2 that holds the first potential Vh1 and a first contraction element PE3 that drops the potential with a predetermined gradient from the first potential Vh1 to the reference potential VB are included.

  The operation when the ejection pulse DP1 is supplied to the piezoelectric element 35 will be described. First, when the first expansion element PE1 is supplied, the piezoelectric element 35 contracts. When the piezoelectric element 35 contracts, the volume of the pressure chamber 32 expands. And the expansion | swelling state of the pressure chamber 32 is hold | maintained over the supply period of 1st hold element PE2. Next, when the first contraction element PE3 is supplied, the piezoelectric element 35 expands. When the piezoelectric element 35 extends, the volume of the pressure chamber 32 contracts. Thereby, the functional liquid 33 in the pressure chamber 32 is pressurized, and the droplets 36 are discharged from the nozzle 31.

  Next, the configuration of the fine vibration pulse DP2 will be described. The fine vibration pulse DP2 includes a stirring vibration pulse SDP10 and a heating vibration pulse HDP20. As shown in FIG. 3B, the stirring vibration pulse SDP10 includes a second expansion element PE11 that raises the potential with a predetermined gradient from the reference potential VB to the second potential Vh2, and a second potential that holds the second potential Vh2. It includes a hold element PE12 and a second contraction element PE23 that drops the potential with a predetermined gradient from the second potential Vh2 to the reference potential VB. Here, the second potential Vh <b> 2 is set in a range where the droplets 36 are not ejected from the nozzle 31. In the present embodiment, for example, the second potential Vh2 employs a potential that is about one third of the first potential Vh1. This will be described in more detail below.

  The second expansion element PE11 of the stirring vibration pulse SDP10 includes a heating vibration pulse HDP20. In the present embodiment, the second expansion element PE11 includes a plurality of heating vibration pulses HDP20. In other words, the second expansion element PE11 is formed by forming the plurality of heating vibration pulses HDP20. Specifically, the second expansion element PE11 includes heating vibration pulses HDP20a to HDP20c. The vibration pulse HDP20a for heating includes an expansion element that increases the potential from the reference potential VB to the potential Vhb, a hold element that holds the potential Vhb, and a contraction element that decreases the potential from the potential Vhb to the potential Vha. The vibration pulse for heating HDP20b includes a hold element that holds the potential Vha, an expansion element that raises the potential from the potential Vha to the potential Vhd, a hold element that holds the potential Vhd, and a contraction that lowers the potential from the potential Vhd to the potential Vhc. Elements. The vibration pulse for heating HDP20c includes a hold element that holds the potential Vhc, an expansion element that raises the potential from the potential Vhc to the second potential Vh2, a hold element that holds the second potential Vh2, and a potential Vhe from the second potential Vh2. A contraction element that lowers the potential to Of these, the expansion element of the heating vibration pulse HDP20c is included in the second expansion element PE11.

  The second hold element PE12 of the stirring vibration pulse SDP10 includes a heating vibration pulse HDP20. In the present embodiment, the second hold element PE12 includes a plurality of heating vibration pulses HDP20. In other words, the second hold element PE12 is formed by forming the plurality of heating vibration pulses HDP20. Specifically, the second hold element PE12 includes heating vibration pulses HDP20c to HDP20f. The heating vibration pulse HDP20c includes an expansion element that increases the potential from the reference potential Vhc to the second potential Vh2, a hold element that holds the second potential Vh2, and a contraction element that decreases the potential from the second potential Vh2 to the potential Vhe. Is included. Note that the hold element and the contraction element of the heating vibration pulse HDP20c are included in the second hold element PE12. The vibration pulse HDP20d for heating includes a hold element that holds the potential Vhe, an expansion element that raises the potential from the potential Vhe to the second potential Vh2, a hold element that holds the second potential Vh2, and a potential Vhe from the second potential Vh2. A contraction element that lowers the potential to The vibration pulse HDP20e for heating includes a hold element that holds the potential Vhe, an expansion element that raises the potential from the potential Vhe to the second potential Vh2, a hold element that holds the second potential Vh2, and a potential Vhe from the second potential Vh2. A contraction element that lowers the potential to The vibration pulse HDP20f for heating includes a hold element that holds the potential Vhe, an expansion element that raises the potential from the potential Vhe to the second potential Vh2, a hold element that holds the second potential Vh2, and a potential Vhc from the second potential Vh2. A contraction element that lowers the potential to Of these, the expansion element and the hold element of the heating vibration pulse HDP20f are included in the second hold element PE12.

  The second contraction element PE13 of the stirring vibration pulse SDP10 includes a heating vibration pulse HDP20. In the present embodiment, the second contraction element PE13 includes a plurality of heating vibration pulses HDP20. In other words, the second contraction element PE13 is formed by forming the plurality of heating vibration pulses HDP20. Specifically, the second contraction element PE13 includes heating vibration pulses HDP20f to HDP20h. The heating vibration pulse HDP20f includes an expansion element that increases the potential from the potential Vhe to the second potential Vh2, a hold element that holds the second potential Vh2, and a contraction element that decreases the potential from the second potential Vh2 to the potential Vhc. Contains. Of these, the hold element and the contraction element of the heating vibration pulse HDP20c are included in the second hold element PE12. The heating vibration pulse HDP20g includes a hold element that holds the potential Vhc, an expansion element that raises the potential from the potential Vhc to the potential Vhd, a hold element that holds the potential Vhd, and a contraction that lowers the potential from the potential Vhd to the potential Vha. Elements. The heating vibration pulse HDP20h lowers the potential from the hold element that holds the potential Vha, the expansion element that raises the potential from the potential Vha to the potential Vhb, the hold element that holds the potential Vhb, and the potential Vhb to the reference potential VB. A contraction element.

  Next, the operation when the stirring vibration pulse SDP10 is supplied to the piezoelectric element 35 will be described. First, when the second expansion element PE11 is supplied, the piezoelectric element 35 contracts. When the piezoelectric element 35 contracts, the volume of the pressure chamber 32 expands. And the expansion state of the pressure chamber 32 is hold | maintained over the supply period of 2nd hold element PE12. Next, when the second contraction element PE13 is supplied, the piezoelectric element 35 expands. When the piezoelectric element 35 extends, the volume of the pressure chamber 32 contracts. Here, the potential difference from the reference potential VB to the second potential Vh2 is set in a range where the droplets 36 are not ejected from the nozzle 31. Furthermore, each of the first time SL1 from the start end to the end of the second expansion element PE11 and the second time SL2 from the start end to the end of the second contraction element PE13 in the stirring vibration pulse SDP10 is the functional liquid in the pressure chamber 32. It is set to 1/2 or more of the 33 natural vibration period Tc. That is, the time during which the potential rises from the reference potential VB in the second expansion element PE11 to the second potential and the time during which the potential falls from the second potential Vh2 in the second contraction element PE13 to the reference potential are respectively determined in the pressure chamber 32. It is set to 1/2 or more of the natural vibration period Tc of the functional liquid 33. For this reason, the functional liquid 33 moves following the contraction and expansion movements of the piezoelectric element 35. Thereby, the functional liquid 33 is agitated and the increase in the viscosity of the functional liquid 33 exposed at the opening of the nozzle 31 can be prevented.

  Next, the operation when the heating vibration pulse HDP20 is supplied to the piezoelectric element 35 will be described. When the expansion element in each of the heating vibration pulses HDP20a to HDP20h is supplied, the piezoelectric element 35 contracts. When the piezoelectric element 35 contracts, the volume of the pressure chamber 32 expands. When the contraction element is supplied after the hold element is supplied, the piezoelectric element 35 expands. When the piezoelectric element 35 extends, the volume of the pressure chamber 32 contracts. Here, the potential difference between the vibration pulses for heating HDP20a to HDP20h is set in a range in which the liquid droplet 36 is not ejected from the nozzle 31. Furthermore, the third time TL1 from the start end to the end of the expansion element or the fourth time TL2 from the start end to the end of the contraction element in each of the heating vibration pulses HDP20a to HDP20h is the characteristic of the functional liquid 33 in the pressure chamber 32. It is set to 1/2 or less of the vibration period Tc. That is, in a short period, the drive signal is transmitted and the piezoelectric element 35 is contracted and expanded, so that the functional liquid 33 in the pressure chamber 32 is heated.

  As mentioned above, according to the said embodiment, the following effects can be acquired.

  (1) By supplying a drive signal including a fine vibration pulse DP2 having a stirring vibration pulse SDP10 and a heating vibration pulse HDP20 to the piezoelectric element 35, the function of the opening of the nozzle 31 is achieved by the action of the stirring vibration pulse SDP10. The liquid 33 is stirred and the functional liquid 33 is heated by the action of the heating vibration pulse HDP20. Thereby, the discharge performance of the droplets 36 can be improved.

  (2) By including the plurality of heating vibration pulses HDP20a to HDP20h in the stirring vibration pulse SDP10, compared with the case where the stirring vibration pulse SDP10 and the plurality of heating vibration pulses HDP20a to HDP20h are provided separately, The entire pulse length of the vibration pulse DP2 can be shortened. As a result, high-frequency ejection becomes possible and productivity can be improved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

  (Modification 1) In the above embodiment, in the configuration of the fine vibration pulse DP2, the heating vibration pulse HDP20 (HDP20a) is applied to the second expansion element PE11, the second hold element PE12, and the second contraction element PE13 of the stirring vibration pulse SDP10. ~ HDP20h) is included, but is not limited to this configuration. For example, the heating vibration pulse HDP20 (HDP20a to HDP20h) is applied to only one of the second expansion element PE11, the second hold element PE12, and the second contraction element PE13 of the stirring vibration pulse SDP10. HDP20a to HDP20h) may be arranged. FIG. 4 is a waveform diagram showing a configuration of a micro vibration pulse according to a modification. FIG. 4A illustrates an example in which the heating vibration pulse HDP20 (HDP20a to HDP20c) is included only in the second expansion element PE11 of the stirring vibration pulse SDP10, and FIG. 4B illustrates the stirring vibration pulse SDP10. FIG. 4C illustrates an example in which the heating vibration pulse HDP20 (HDP20c to HDP20f) is included only in the second hold element PE12. FIG. 4C illustrates the heating vibration pulse only in the second contraction element PE13 of the stirring vibration pulse SDP10. An example in which HDP20 (HDP20f to HDP20h) is included is shown. In this way, discharge conditions can be generated as appropriate in accordance with the state of the various functional liquids 33. Furthermore, you may combine said form. In this way, appropriate discharge conditions can be generated.

  (Modification 2) In the above embodiment, in the configuration of the fine vibration pulse DP2, the second expansion element PE11 includes the heating vibration pulses HDP20a to HDP20c, and the second hold element PE12 includes the heating vibration pulses HDP20c to HDP20f. And the second contraction element PE13 includes the vibration pulses for heating HDP20f to HDP20h, but is not limited to this configuration. For example, the number of heating vibration pulses HDP20 included in each of the second expansion element PE11, the second hold element PE12, and the second contraction element PE13 may be arbitrarily set. Even if it does in this way, the same effect as the above can be acquired.

  DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus, 2 ... Head unit, 10 ... Carriage, 12 ... Discharge head, 21, 22 ... Ultraviolet irradiation part, 28 ... X scanning axis, 30 ... Nozzle plate, 31 ... Nozzle, 32 ... Pressure chamber, 33 ... functional liquid, 34 ... vibration plate, 35 ... piezoelectric element, 36 ... droplet, 39 ... flow path forming substrate, 40 ... stage, DP1 ... discharge pulse, DP2 ... fine vibration pulse, SDP10 ... stirring pulse, HDP20 ( HDP20a to HDP20f) ... vibration pulse for heating.

Claims (4)

A discharge head having a pressure chamber communicating with the nozzle, and a pressure generating section that causes pressure fluctuation in the functional liquid in the pressure chamber;
A control signal that generates a drive signal including a micro-vibration pulse that does not eject droplets from the nozzle, and that drives the pressure generator based on the drive signal,
In the control unit,
A droplet discharge device that generates the fine vibration pulse including a stirring vibration pulse for stirring the functional liquid and a heating vibration pulse for heating the functional liquid. The droplet discharge device according to claim 1,
In the control unit,
The droplet that is a vibration pulse for stirring, wherein the expansion element that expands the pressure chamber or the contraction element that contracts the pressure chamber includes at least a part of the vibration pulse for heating. Discharge device. In the liquid droplet ejection apparatus according to claim 1 or 2,
In the control unit,
Each of the time from the start end to the end of the expansion element and the time from the start end to the end of the contraction element in the stirring vibration pulse is set to ½ or more of the natural vibration period Tc of the functional liquid in the pressure chamber. A droplet discharge device characterized by the above. In the liquid droplet ejection apparatus according to claim 1 or 2,
In the control unit,
The time from the start end to the end of the expansion element or the time from the start end to the end of the contraction element in the vibration pulse for heating is set to ½ or less of the natural vibration period Tc of the functional liquid in the pressure chamber. A droplet discharge device characterized by the above.

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