JP2008119873A - Liquid droplet delivery apparatus and liquid droplet delivery method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet delivery apparatus capable of driving by a low electric voltage and performing downsizing while corresponding to a high image quality and a high speed imaging, and to provided a liquid droplet delivery method. <P>SOLUTION: The liquid droplet delivery apparatus equipped with a nozzle 21 for delivering an ink with polarity and a liquid room 23 communicating with the nozzle 21 and filled with the ink, is characterized in that in the liquid room 23, an electrically-conductive polymer film 50 capable of expanding and shrinking by passing an electric current is provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a droplet discharge device and a droplet discharge method.

  2. Description of the Related Art Conventionally, printers using a droplet discharge device are known as printers that enable high image quality and high-speed drawing. The droplet discharge device includes a droplet discharge head having a liquid chamber whose internal volume changes, and draws by discharging droplets from the nozzle while scanning the head.

As a head actuator in such a head, a piezoelectric element represented by PZT (Pb (Zr _x Ti _1-x ) O ₃ ) has been conventionally used. In addition to the case where a piezoelectric element is used, for example, as shown in Patent Documents 1 and 2, by using a shape memory polymer thin film and a heating element and applying a voltage to the heating element, the shape memory is generated together with the heat generation of the heating element. There is a droplet discharge head that discharges ink droplets when a polymer thin film is heated and the shape memory polymer thin film expands and contracts.
JP-A-2-253963 JP-A-4-33863

However, in the above-described liquid droplet ejection heads disclosed in Patent Documents 1 and 2, since the shape memory polymer thin film changes its volume through the temperature change of the heating element and ejects ink droplets, the shape memory polymer There is a problem that the responsiveness of the expansion and contraction deformation of the thin film is poor, the drawing quality is deteriorated and high-speed drawing cannot be performed.
In addition, a head actuator using a piezoelectric element has a problem that the drive voltage is as high as 20 to 30 V and the drive structure is complicated, so that the device itself becomes large.

  Accordingly, the present invention has been made to solve the above-described problems, and is capable of being driven at a low voltage while being compatible with high image quality and high-speed drawing, and capable of miniaturization. An apparatus and a droplet discharge method are provided.

In order to achieve the above object, a liquid droplet ejection apparatus according to the present invention includes a liquid droplet ejection nozzle that ejects a liquid material having polarity, a liquid that communicates with the liquid droplet ejection nozzle and is filled with the liquid material. And a chamber, wherein the liquid chamber is provided with a conductive polymer film capable of expanding and contracting when energized.
The conductive polymer film expands and contracts due to a dopant ion entering and exiting the conductive polymer film by energization, a structural change in the polymer chain of the conductive polymer film, and the like. By disposing the conductive polymer film in the liquid chamber, it is possible to cause a change in pressure due to a change in the volume in the liquid chamber and discharge a droplet. Accordingly, the drive structure of the droplet discharge device can be simplified while supporting high image quality and high-speed drawing, the device can be miniaturized, and the nozzle pitch can be formed with high density. Further, since the conductive polymer film expands and contracts at a low voltage, the power source can be reduced in size. Therefore, the droplet discharge device can be miniaturized and a portable device can be realized.

The conductive polymer film is attached to a first wall constituting the liquid chamber, and at least a part of the second wall constituting the liquid chamber is provided with a current-carrying portion formed of a semiconductor material. A voltage applying means for applying a voltage is provided between the conductive polymer film and the energizing portion.
By comprising in this way, a voltage can be applied between a liquid body and a conductive polymer film via an electricity supply part, and a conductive polymer film can be expanded-contracted and deformed. Therefore, it is not necessary to form an electrode in the liquid chamber, and the manufacturing cost can be reduced.

On the other hand, a droplet discharge method according to the present invention includes a droplet discharge nozzle that discharges a liquid material having polarity, a liquid chamber that communicates with the droplet discharge nozzle and is filled with the liquid material, and the liquid chamber A droplet discharge method of a droplet discharge device provided with a conductive polymer film that can be expanded and contracted by energization, wherein the liquid material filled in the liquid chamber and the conductive high film The liquid material is discharged by expanding and contracting the conductive polymer film by applying a voltage to the molecular film.
The conductive polymer film expands and contracts due to a dopant ion entering and exiting the conductive polymer film by energization, a structural change in the polymer chain of the conductive polymer film, and the like. By disposing the conductive polymer film in the liquid chamber, it is possible to cause a change in pressure due to a change in the volume in the liquid chamber and eject a droplet. Accordingly, it is possible to drive the droplet discharge device with a low voltage while supporting high image quality and high-speed drawing, and it is possible to reduce the size of the droplet discharge device.

Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.
(First embodiment)
FIG. 1 is an exploded perspective view of the droplet discharge device, and FIG. 2 is a plan view of the droplet discharge device. 3 is a cross-sectional view taken along the line AA in FIG.

  As shown in FIGS. 1 to 3, the droplet discharge device 1 includes a flow path forming substrate 20 (second wall) and an actuator forming substrate 30 (first wall) disposed to face the flow path forming substrate 20. Is formed. On each of the substrates 20 and 30, there are arranged a droplet discharge nozzle 21 (hereinafter referred to as “nozzle”) that discharges a liquid material (hereinafter referred to as “ink”) and a liquid chamber 23 that communicates with the nozzle 21 and is filled with ink. Is formed.

  The flow path forming substrate 20 is made of an n-type semiconductor material that can move electrons. Specifically, it is made of a silicon single crystal substrate into which ions such as phosphorus (P) and arsenic (As) are implanted at a high concentration, and has a thickness of, for example, 200 μm. The flow path forming substrate 20 is configured as an energization portion that can energize the entire flow path forming substrate 20 by ion-implanting the entire flow path forming substrate 20 at a high concentration. On the lower surface of the flow path forming substrate 20, nozzles 21 for ejecting ink are arranged. The nozzle 21 is formed with a diameter of about 10 μm and a depth of 50 μm, for example, and this size can be changed according to the amount of ink ejected, the ejection speed, and the ejection frequency.

  Further, the nozzle 21 has a communication portion 22 formed toward the upper surface of the flow path forming substrate 20, and communicates with the liquid chamber 23 via the communication portion 22. The liquid chamber 23 is formed in a gap between a flow path forming substrate (second wall) 20 and an actuator forming substrate (first wall) 30 described later, and has a comb-like shape in plan view in the nozzle arrangement direction of the flow path forming substrate 20. Are installed side by side. The liquid chamber 23 is formed, for example, with a width of about 50 μm, an interval of about 20 μm, a length of about 500 μm, and a height of about 100 μm.

The liquid chamber 23 is filled with ink having polarity. The ink is preferably an aqueous solution or a polar organic solvent solution. The polar organic solvent contains 10 to 30% of dimethylformamide (C ₃ H ₇ NO), dimethyl sulfoxide ((CH ₃ ) ₂ SO), 1,4-dioxane (C ₄ H ₈ O ₂ ) in the ink solution. It can obtain by adding in a ratio.

  In addition, a reservoir 24 is formed on the opposite side of the communication portion 22 via the liquid chamber 23. The reservoir 24 preliminarily holds ink to be supplied to the liquid chambers 23, is continuously formed in the nozzle arrangement direction of the flow path forming substrate 20, and communicates with each liquid chamber 23. The flow path connecting the reservoir 24 and the liquid chamber 23 is formed with a narrower width than the liquid chamber 23, and the flow path resistance of the ink flowing from the reservoir 24 into the liquid chamber 23 is kept constant.

  On the other hand, the actuator forming substrate 30 disposed opposite to the flow path forming substrate 20 is made of a silicon single crystal substrate, and an ink supply path 31 is formed in the vicinity of the end of the actuator forming substrate 30. The ink supply path 31 penetrates from the opening 32 on the upper surface of the actuator forming substrate 30 to the lower surface, and communicates with the reservoir 24.

  An actuator holding portion 39 is formed on the lower surface side of the actuator forming substrate 30 through a step. An insulating layer 33 made of silicon dioxide or the like is formed on the surface of the actuator holding portion 39. A first wiring 34 made of aluminum or the like is formed on the surface of the insulating layer 33. One end of the first wiring 34 is connected to a terminal of a driving IC 35 disposed outside the liquid chamber 23, and the other end is It is drawn into the liquid chamber 23 and connected to a conductive polymer film 50 described later. A common wire (not shown) is drawn from the other terminal of the driving IC 35 and connected to the flow path forming substrate 20.

  The surface of the first wiring 34 drawn into the liquid chamber 23 is covered with an insulating layer 37 made of silicon dioxide or the like. The insulating layer 37 is formed with a contact portion 38 that exposes the first wiring 34.

  Here, a conductive polymer film 50 is formed on the surfaces of the insulating layers 33 and 37 in the liquid chamber 23 as an actuator made of a conductive polymer material. For example, the conductive polymer film 50 is formed with a thickness of about 1.0 μm, a width of about 30 μm, and a length of about 500 μm. In addition, polypyrrole, polyaniline, polythiophene, polyacetylene, or the like can be used as a material for forming the conductive polymer film 50. The conductive polymer film 50 may be a conductive polymer containing pyrrole and / or a pyrrole derivative in the molecular chain. desirable.

  The conductive polymer film 50 is connected to the first wiring 34 exposed from the contact portion 38 and is placed so as to be energized. The driving IC applies a voltage between the conductive polymer film 50 connected to the first wiring 34 and the flow path forming substrate (current-carrying part) 20 connected to the common wiring. That is, the driving IC functions as a voltage applying unit. As a result, the conductive polymer film 50 is energized through the ink having the polarity filled in the liquid chamber 23, and the conductive polymer film 50 expands and contracts.

(Droplet discharge method of droplet discharge device)
Next, a droplet discharge method of the droplet discharge apparatus 1 in the present embodiment will be described with reference to FIG.
First, an ink supply device (not shown) connected to the ink supply path 31 is driven. Then, the ink delivered from the ink supply device is supplied to the reservoir 24 via the ink supply path 31 and then filled into the internal flow path to the nozzle 21.
Next, a voltage is applied by a power source (not shown). Then, the ink having the polarity filled in the liquid chamber 23 becomes the electrolytic solution, and electricity is passed between the flow path forming substrate 20 and the conductive polymer film 50 through this ink. Thereby, the conductive polymer film 50 expands and contracts.

  The expansion and contraction of the conductive polymer film 50 is performed by the entry / exit of dopant ions into / from the conductive polymer, the structural change of the polymer chain, and the like by applying a voltage and switching the polarity. That is, when a positive voltage is applied to the conductive polymer, a structural change occurs simultaneously with the uptake of negative ions in the ink, and the conductive polymer film 50 expands. On the other hand, when a negative voltage is applied to the conductive polymer film, a structural change occurs simultaneously with the uptake of positive ions in the ink, and the conductive polymer film 50 contracts.

Then, by controlling this structural change with a voltage waveform, the volume in the liquid chamber 23 is changed, and a pressure change in the liquid chamber 23 is generated, and ink is ejected from the nozzle 21. The volume change rate of the conductive polymer film 50 at this time can be increased by 30% or more as compared with a conventional piezoelectric element (for example, PZT (Pb (Zr _x Ti _1-x ) O ₃ )).

(Manufacturing method of droplet discharge device)
Next, the manufacturing method of the droplet discharge device in the present embodiment will be described with reference to FIGS. FIG. 4 is a cross-sectional view taken along line BB in FIG. 2 and is a process diagram of the droplet discharge device. In FIG. 4, only the conductive polymer film 50 is shown inside the actuator forming substrate 30 and the insulating layer 33 and the like are omitted.
First, as shown in FIG. 4A, the flow path forming substrate 20 is formed.
Specifically, a silicon single crystal substrate into which ions are implanted at a high concentration is ground to a thickness of about 200 μm, for example.

  Next, the nozzle 21 is formed on the lower surface of the flow path forming substrate 20 by using a photolithography technique. Specifically, a resist film is formed on the entire lower surface of the flow path forming substrate 20, and is exposed and developed to remove the resist film in the region where the nozzle 21 is to be formed. Next, the flow path forming substrate 20 is dry-etched using the resist film as a mask to form the nozzle 21.

Next, the liquid chamber 23 is formed on the upper surface of the flow path forming substrate 20. Specifically, the liquid chamber 23 is formed by performing dry etching of the flow path forming substrate 20 through the resist mask exposed and developed by the photolithography process, as in the method of forming the nozzle 21.
Further, the communication portion 22 and the reservoir 24 are formed by the same formation method as that for the liquid chamber 23.

Next, the actuator forming substrate 30 is formed.
Specifically, the ink supply path 31 and the actuator holding part 39 are formed by performing dry etching on the lower surface of the actuator forming substrate 30 through a resist mask exposed and developed by a photolithography process. Next, dry etching is similarly performed from the upper surface of the actuator forming substrate 30 to form the opening 32 of the ink supply path 31 and to connect the ink supply path 31.

Next, the 33 insulating layer 33 is formed on the surface of the actuator holding portion 39. Specifically, after the insulating layer 33 is formed on the entire lower surface of the flow path forming substrate 20 by a CVD method or the like, the insulating layer 33 is patterned by performing dry etching through a resist mask exposed and developed by a photolithography process. .
Next, the first wiring 34 is formed on the insulating layer 33. Specifically, after the first wiring 34 is formed by sputtering or the like, the first wiring 34 is patterned by performing dry etching through a resist mask exposed and developed by a photolithography process.

  Then, an insulating layer 37 is formed on the first wiring 34. Specifically, the insulating layer 37 is formed on the entire lower surface of the flow path forming substrate 20 by the CVD method in the same manner as the method for forming the insulating layer 33. Next, dry etching is performed through a resist mask exposed and developed by a photolithography process, and the insulating layer 37 is patterned. At this time, a part of the first wiring 34 is exposed to form a contact portion 38 between the first wiring 34 and the conductive polymer film 50. On the other hand, the other end of the first wiring 34 is connected to a terminal of the driving IC 35 disposed in the actuator holding portion 39 outside the liquid chamber 23.

  Next, the conductive polymer film 50 is formed on the surfaces of the insulating layer 33 and the insulating layer 37. Specifically, a material for forming the conductive polymer film 50 is applied by an electric field polymerization method or a spin coating method. Thereafter, dry etching is performed through a resist mask exposed and developed by a photolithography process, and the conductive polymer film 50 is patterned. The dimensions of the conductive polymer film 50 are, for example, a thickness of about 1.0 μm, a width of about 30 μm, and a length of about 500 μm, and are approximately the same shape as a conventional piezoelectric element.

  Next, as shown in FIG. 4B, the flow path forming substrate 20 and the actuator forming substrate 30 are bonded together with an adhesive. Then, the other terminal of the driving IC 35 is connected to the flow path forming substrate 20 via the common wiring, whereby the droplet discharge device 1 in the present embodiment can be obtained.

  Therefore, according to the above-described embodiment, the conductive polymer film 50 that can be expanded and contracted by energization is provided in the liquid chamber 23. With this configuration, by applying a voltage between the conductive polymer film 50 and the ink having polarity, the dopant ions of the conductive polymer film 50 enter and exit the conductive polymer film 50 and the structure of the polymer chain. The conductive polymer film 50 itself expands and contracts due to a change or the like, thereby causing a pressure change due to a change in the volume in the liquid chamber 23 and ejecting ink. A conventional droplet discharge device has a structure in which a piezoelectric element is disposed outside a flexible vibration plate, and a pressure change is generated in the liquid chamber via the vibration plate. Compared to this, in the droplet discharge device 1 of this embodiment, since the conductive polymer film 50 is provided in the liquid chamber 23, a diaphragm is not necessary. As a result, the drive structure can be simplified while supporting high image quality and high-speed drawing, and the apparatus can be miniaturized. Furthermore, it is possible to increase the nozzle pitch.

  In addition, since the conductive polymer film 50 expands and contracts at 1 to 3 V, it can be driven at a lower voltage than the case where the piezoelectric element requires a drive voltage of 20 to 30 V, and the power supply is downsized. can do. Therefore, the droplet discharge device can be downsized, and a portable device driven by a dry battery or the like can be realized.

  Further, in comparison with a droplet discharge device provided with an electrostatic actuator, similarly, since a diaphragm is not required, the drive structure is simplified and the device can be driven at a low voltage, so that the size of the device can be reduced. Can be realized.

Further, since the nozzle 21 is integrally formed with the flow path forming substrate 20, the liquid droplet ejection apparatus 1 can be simply bonded to the flow path forming substrate 20 and the actuator forming substrate 30 on which the conductive polymer film 50 is disposed. Can be formed.
Further, the actuator forming substrate 30 and the flow path forming substrate 20 constitute a liquid chamber 23, and the conductive polymer film 50 is mounted on the actuator forming substrate 30, and the flow path forming substrate 20 is formed of a semiconductor material. A current-carrying part is provided, and a voltage is applied between the conductive polymer film 50 and the current-carrying part. With this configuration, a voltage can be applied between the ink and the conductive polymer film 50 via the energization unit, and the conductive polymer film 50 can be expanded and contracted. Therefore, it is not necessary to form an electrode in the liquid chamber 23, and the manufacturing cost can be reduced.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. For example, it can be applied to a printer unit such as a handy terminal (portable terminal) by incorporating such a droplet discharge device.

  Further, since the volume change amount can be improved by increasing the film thickness of the conductive polymer film, the same discharge amount can be obtained even if the dimensions of the ink chamber are reduced. Furthermore, in the present embodiment, the entire flow path forming substrate is ion-implanted at a high concentration to form a current-carrying part, but only a part facing the liquid chamber is ion-implanted to a high concentration to form a current-carrying part. May be. An electrode may be formed in the liquid chamber.

It is a disassembled perspective view of the droplet discharge apparatus in embodiment of this invention. It is a top view of a droplet discharge device in an embodiment of the present invention. It is sectional drawing which follows the AA line of FIG. 2 of the droplet discharge apparatus in embodiment of this invention. It is process drawing of the droplet discharge apparatus in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge apparatus 20 ... Flow path formation board | substrate (2nd wall) 21 ... Nozzle (droplet discharge nozzle) 23 ... Liquid chamber 30 ... Actuator formation board | substrate (1st wall) 50 ... Conductive polymer film

Claims (3)

A droplet discharge nozzle for discharging a liquid material having polarity;
A liquid chamber communicating with the droplet discharge nozzle and filled with the liquid material;
In a liquid droplet ejection apparatus comprising:
A liquid droplet ejection apparatus, wherein a conductive polymer film capable of expanding and contracting when energized is provided in the liquid chamber. The conductive polymer film is attached to a first wall constituting the liquid chamber,
At least a part of the second wall constituting the liquid chamber is provided with an energization part made of a semiconductor material,
The liquid droplet ejection apparatus according to claim 1, further comprising a voltage application unit configured to apply a voltage between the conductive polymer film and the energization unit. A droplet discharge nozzle for discharging a liquid material having polarity;
A fluid chamber communicating with the droplet discharge nozzle and filled with the liquid material;
A conductive polymer film provided in the liquid chamber and capable of being expanded and contracted by energization;
A droplet discharge method for a droplet discharge apparatus comprising:
Applying a voltage between the liquid material filled in the liquid chamber and the conductive polymer film to expand and contract the conductive polymer film to discharge the liquid material, Droplet discharging method.

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