JP2011230122A - Droplet injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a droplet injection device which is inexpensive and excellent in convenience on the production, and which secures the droplet injection with high accuracy by increasing the injection capacity of a piezoelectric actuator to effect the compact unitization.SOLUTION: In the droplet injection device, an injection nozzle 105 having an injection aperture with a microdiameter is fitted on the lower end face of the lengthwise type casing 101, while a cylinder hole 120 is opened at the upper part of the same to arrange a plunger 104 at the cylinder hole so that it can be slid. In the casing 101, a lamination type piezoelectric element 103 the upper face of which is fitted to a fitting member 113 fixed to the casing is arranged to abut the upper face of the plunger to the lower end of the piezoelectric element. A liquid reservoir 131 that is linked to the injection aperture is formed at the tip of the cylinder hole 120, and the supply channel 134 of a feed hopper pipe 106 to introduce an injection liquid is connected to the liquid reservoir. The injection liquid within the liquid reservoir 131 supplied from the supply channel 134 is injected from the injection aperture of the injection nozzle 105 under pressure by the driving of the piezoelectric element 103.

Description

  The present invention relates to a droplet ejection apparatus, and more specifically, ejects a liquid material such as a conductive paste (metal fine particle dispersion, solder material) and a liquid resist as droplets in industrial production fields such as electronic parts, In liquid medicine, liquid samples are ejected as droplets, and high-viscosity fine particle liquids for molding fine objects mixed with metals, ceramics, resins, etc. are ejected. The present invention relates to a droplet ejecting apparatus used for ejecting as.

  Taking the production process of electronic components as an example of the prior art, with the recent demands for smaller and higher performance electronic devices, highly integrated micro wiring patterns are also required in circuit board circuit formation. In order to meet the demand, instead of the conventional screen printing method and photolithographic etching method, the conductive paste itself is improved and a droplet ejection device is used, and the conductive paste is ejected as droplets from the ejection nozzle. A method for directly drawing a wiring pattern has been proposed. As a droplet ejecting apparatus used therefor, an inkjet ejecting apparatus using a piezoelectric element as a drive source is generally used.

Specifically, as disclosed in Japanese Patent Laid-Open No. 10-204350 (Patent Document 1), a diaphragm and a piezoelectric element are disposed in a cavity containing ink (metal fine particle dispersion), and the piezoelectric element The diaphragm is deformed by a fine expansion and contraction generated by applying a voltage, and the ink in the cavity is pressurized by the deformation action and ejected as droplets from the nozzle.
In addition, the ink jet device disclosed in Japanese Patent Application Laid-Open No. 2004-207510 (Patent Document 2) uses a piezo element that deforms when a voltage is applied, and ink (metal fine particle dispersion) is stored by the action of the piezo element. It is a device that discharges conductive ink as fine droplets by bending the wall of the pressure chamber or by forming the wall of the pressure chamber itself with a piezo element.

Japanese Patent Laid-Open No. 10-204350 (refer to FIGS. 1 and 2 and the description thereof) JP 2004-207510 A (refer to FIGS. 3B and 4B and the description thereof)

In any of the above conventional droplet ejection devices, the driving force of the piezoelectric actuator is applied to the side of an ink tank such as a cavity or a pressure chamber that contains ink (a dispersion liquid containing metal fine particles, hereinafter referred to as conductive ink). The method of directly applying the pressure, that is, the ink jet method as a printing technique employed in the printer is merely applied as it is.
However, in order to efficiently draw and produce a wiring pattern serving as an electronic circuit, the conductive ink is required to have a higher viscosity dispersion than the viscosity of ordinary printing ink (10 mPa · s or less). In addition, combined with the miniaturization of the nozzle hole diameter accompanying the miniaturization of the wiring, a larger radiant output than the conventional ink jet method is required.
However, in the above-described conventional apparatus, smooth droplet ejection of the conductive ink cannot be expected due to the output limit of the piezoelectric actuator, and direct drawing of a highly accurate wiring pattern cannot be ensured. Further, in order to incorporate a plurality of sets as a droplet ejecting device, a compact form that is unitized such as a long and narrow pencil type or a short column type is required. However, in the above conventional device, the structure of the piezoelectric actuator, the ink tank In view of the arrangement structure of the diaphragm and the piezoelectric element, unitization was not desired. Furthermore, considering the convenience and cost in production, assembly and ease of maintenance are required in a specific structure.
These problems are not limited to the case of ejecting droplets of conductive ink, and the same applies to the case of ejecting droplets of a liquid material / sample having a certain degree of viscosity.

  In view of the above-described conventional circumstances, the present invention increases droplet output as a piezoelectric actuator, guarantees high-precision droplet ejection, enables compact unitization, and has excellent droplet manufacturing convenience. The object is to provide the device at a low cost.

In such a droplet ejection device of the present invention, an injection nozzle having a minute diameter injection hole is provided at the tip of a vertically thin casing, a laminated piezoelectric element is disposed in the casing, and the piezoelectric element is driven by a driving source. The plunger is housed in a cylinder hole so as to be slightly extendable and retractable, a liquid reservoir chamber connected to the injection hole is formed at the tip of the cylinder hole, and a supply port pipe for introducing the injection liquid is supplied to the liquid reservoir chamber The passage is connected so that the injection liquid in the liquid reservoir supplied from the supply passage is pressurized by driving the piezoelectric element to be injected from the injection hole of the injection nozzle, and the casing has an injection nozzle at the lower end surface. A laminated piezoelectric element in which a cylinder hole is opened in the upper part and a plunger is slidably disposed in the cylinder hole, and an upper end surface is attached to an attachment member fixed to the casing. By disposing the child, a structure obtained by abutting the upper surface of the plunger to the lower end of the piezoelectric element (claim 1).
According to the present invention, the piezoelectric element slightly expands and contracts when a voltage is applied, so that the plunger is slightly expanded and contracted toward the liquid reservoir chamber at the tip of the cylinder hole by using the piezoelectric element as a drive source, By compressing the pressure and pressurizing the injection liquid, the injection liquid is injected from the injection hole of the injection nozzle, and when the plunger is contracted, the injection liquid is replenished to the liquid reservoir chamber via the supply path. The injection liquid can be ejected as droplets.

  Further, in the present invention, since the liquid reservoir is a minute volume formed at the tip of the vertical thin casing, the compressive force of the liquid reservoir by the plunger, that is, the pressure of the injection liquid is large and large. The injection liquid can be injected from the injection nozzle with a radiant output. In addition, since the casing has a vertically thin type and a piezoelectric element, a plunger, a liquid storage chamber, and the like are disposed in the casing, a compact external form such as a pencil type or a short column type can be obtained. Even if the piezoelectric element with the increased or decreased number of layers is used to adjust the radiant power, since only the length of the casing is changed, a pencil type or short column type compact form is secured.

An injection liquid is supplied and replenished to the liquid reservoir chamber through a supply path of a supply port pipe. As a preferable specific configuration, a supply ring is provided above the injection nozzle. The upper chamber of the liquid reservoir chamber is constituted by an opening formed in the center thereof, and the supply ring is provided with an introduction path leading to the upper chamber on the back surface, and the introduction path is connected to the injection liquid supply path. Further, a backflow prevention means such as a weir is formed in the introduction path (claim 2).
According to the second aspect, the injection liquid is prevented from flowing back to the introduction path when the liquid reservoir chamber is pressurized.
Of course, it is optional that no supply ring is provided above the injection nozzle. In this case, an introduction path leading to the liquid storage chamber is formed on the upper surface of the injection nozzle and the supply path for supplying the injection liquid is provided. The backflow prevention means may be formed in the introduction path by communicating with the path (Claim 3).

In the present invention, in order to reinforce the output of the piezoelectric element and increase the compressive force of the liquid reservoir chamber by the plunger, and in order to improve the injection property of the injection liquid, the following means is preferably adopted.
That is, a diaphragm is provided on the critical surface between the cylinder hole and the liquid reservoir, and a connecting member is provided for causing the diaphragm to follow the microscopic expansion and contraction of the plunger (Claim 4). Instead of forming the introduction path on the upper surface of the injection nozzle, it is also possible to form the introduction path and the backflow prevention means in the diaphragm.
Further, the injection nozzle has an injection hole with a small diameter at the tip, and the liquid reservoir chamber is preferably formed in a horn shape so that the diameter is gradually reduced toward the injection hole (Claim 6), A plurality of guide rims or guide grooves are spirally formed in the liquid storage chamber (claim 7).

Further, in the present invention, it is necessary to form a liquid storage chamber and an injection hole in the injection nozzle, and the injection nozzle may be formed as a single member, but in consideration of manufacturing convenience and finishing accuracy. Then, it is constituted by two members, a nozzle holder and a nozzle tube fitted therein, the injection hole is formed at the tip of the nozzle tube, and the liquid reservoir chamber is formed between the nozzle holder and the nozzle tube. Good (claim 8).
In the present invention, various liquid materials and samples such as the conductive ink and resin solution can be used as the injection liquid. As one of the selection materials, the conductive ink, that is, the wiring containing metal fine particles is used. The invention is applied to a circuit drawing dispersion.

According to the present invention, since the ejection liquid can be ejected from the ejection nozzle with a large radiant output by the plunger, high-accuracy and reliable droplet ejection is ensured even when the ejection liquid such as highly viscous conductive ink is used. In addition, it is possible to provide a device capable of being unitized by accommodating an internal component member in a casing and exhibiting a pencil-type or short-column type compact external form.
The overall structure is simplified by the casing structure and the support structure of the piezoelectric element, and the number of parts can be reduced and the manufacturing can be easily and inexpensively provided.
According to the second and third aspects of the present invention, it is possible to prevent the injection liquid from flowing back to the introduction path when the liquid reservoir is pressurized, thereby enabling stable supply / injection of the injection liquid.

According to the fourth aspect of the present invention, the diaphragm that follows the fine expansion and contraction movement of the plunger further enhances the compressive force of the liquid storage chamber and increases the responsiveness of the expansion and contraction operation of the liquid storage chamber, thereby improving the liquid drainage of the injection liquid. In addition, the sealing performance in the liquid storage chamber can be improved, and in claim 5, various inflow channels having various groove shapes including the backflow prevention means are efficiently produced by etching the diaphragm. And can be provided at low cost.
According to the sixth aspect, the pressure increasing action of the injection liquid in the liquid storage chamber can be further enhanced by the shape of the inner surface from the liquid storage chamber to the injection hole.
Further, according to the seventh aspect, since the injection liquid is guided to the axis of the injection hole by the rectifying action by the spiral guide strip or the guide groove, the straightness of the injection liquid is improved and the predetermined position is accurately obtained. Can be injected.

According to the eighth aspect, the liquid reservoir chamber and the nozzle hole can be easily molded and finished with high accuracy.
According to the ninth aspect of the present invention, a wiring pattern can be drawn efficiently and surely, and an extremely fine pattern can be drawn by making the injection hole have a small diameter, which is a direct drawing method that replaces the conventional screen printing method and photolithography etching method. Can be provided.

1 is a cross-sectional side view showing a droplet ejection apparatus according to a first embodiment of the present invention. It is a three-dimensional view showing an element holder and a piezoelectric element. It is a cross-sectional side view which expands and shows the injection case part of a casing. FIG. 4 is a separation view of the injection case portion of FIG. 3. It is a cross-sectional side view of the injection case part which shows another embodiment. It is a cross-sectional side view of the injection case part which shows other embodiment. FIG. 7 is a three-dimensional plan view of the nozzle body in FIG. 6. It is a cross-sectional side view of the injection case part which shows other embodiment. It is a cross-sectional side view which shows the embodiment which improved the inner surface shape of the liquid storage chamber. FIG. 10 is a cross-sectional plan view taken along line (10)-(10) in FIG. 9. It is a cross-sectional side view which shows the other embodiment which improved the inner surface shape of the liquid storage chamber. FIG. 12 is a cross-sectional plan view taken along line (12)-(12) in FIG. 11. It is a cross-sectional side view which shows the droplet injection apparatus of 2nd Example of this invention. FIG. 14 is a cross-sectional bottom view taken along line (14)-(14) in FIG. 13.

An embodiment of the present invention will be described with reference to the drawings in the case of a droplet ejection device used for a direct drawing method of a wiring pattern for supplying conductive ink as an ejection liquid.
1 to 12 show a first embodiment, and FIG. 1 is a cross-sectional side view showing the entire apparatus, in which reference numeral 1 is a casing, 2 is an element holder, 3 is a piezoelectric element, and 4 is a plunger. Reference numeral 5 denotes an injection nozzle, and reference numeral 6 denotes a supply port pipe for supplying conductive ink to the injection nozzle 5.

The casing 1 is composed of a drive case portion 1a made of a long metal tube and an injection case portion 1b integrally connected to the lower end of the casing 1 by bolting, and has a vertically thin external appearance as a whole. A lid plate 1c is bolted to the upper end of the part 1a and is detachably sealed.
An element holder 2 to which the piezoelectric element 3 is attached and held is inserted into the drive case portion 1a, and the upper surface of the holder 2 is fixed to the lid plate 1c by bolts 11 and 11, and the element holder 2 is fixed. The substantially upper half is brought into intimate contact with the inner surface of the drive case portion 1a, while the lower half is separated from the inner surface of the drive case portion 1a so that it can be slightly expanded and contracted.

The element holder 2 will be described with reference to the three-dimensional view of FIG. 2. The element holder 2 is provided with a substantially rectangular plate body having a storage hole 12 that is long in the longitudinal direction, and protrudes downward integrally from the bottom wall of the storage hole 12. A connecting arm 2a is provided, and an engaging surface 13a constituting one half of the corrugated coupling is formed at the tip of the connecting arm 2a. Further, the element holder 2 is provided with an appropriate thinned portion 14 in a substantially lower half portion of the side wall, and an elastic portion 15 having a thin side wall formed in a corrugated shape. 2a is allowed to slightly extend and contract.
A meshing portion 13b constituting the other half of the corrugated coupling integrally formed on the upper portion of the plunger 4 is joined to the meshing surface 13a of the connecting arm 2a in a meshing manner and fastened by a tightening screw 16. The plunger 4 and the element holder 2 are integrated with each other via the connecting arm 2a.
Then, the piezoelectric element 3 is fitted into the housing hole 12 of the element holder 2 and attached integrally.

The piezoelectric element 3 is a laminated type in which, for example, a piezoelectric material mainly composed of PZT (lead zirconate titanate) and internal electrodes are alternately stacked, and a displacement in the laminating direction (longitudinal direction) is applied by applying a voltage. In the present invention, a rectangular shape is used so as to be arranged in the narrow casing 1 and output intensively toward the plunger 4.
The piezoelectric element 3 is fitted and accommodated in the accommodation hole 12 of the element holder 2 and its upper surface is fixed to the element holder 2 by adhesion or the like, and a slight gap is formed between the side surface and the element holder 2. Keep it. Further, the lower surface of the piezoelectric element 3 is brought into contact with the bottom wall of the housing hole 12 to be engaged with the element holder 2. However, since the piezoelectric element 3 has a weak restoring force on the contraction side after being expanded, the element holder 2. The elastic part 15 is fitted and held in the storage hole 12 in a state where the elastic force is left, that is, in a state where a thin waveform is held.

A power cord 17 is wired to the piezoelectric element 3 and slightly expands and contracts depending on the frequency and waveform of the voltage applied by the power cord 17, and the plunger 4 connected to the element holder 2 as a drive source is finely moved. Extend and contract. That is, when the piezoelectric element 3 is extended, the elastic part 15 of the element holder 2 is extended and the plunger 4 is lowered, and when the voltage application is stopped, the element holder 2 and the piezoelectric element 3 are moved by the elastic restoring force of the elastic part 15. The plunger 4 is contracted to raise the plunger 4, and the plunger 4 is slightly expanded and contracted at high speed by the repeated operation.
Note that the length of the element holder 2 and thus the length of the casing 1 is set depending on the number of stacked piezoelectric elements 3, and the entire apparatus is not limited to the pencil type as shown in the illustrated example, but is shorter than the pencil type. It becomes.

The injection case portion 1b will be described with reference to the enlarged views of FIGS. 3 and 4. A cylinder hole 20 into which the plunger 4 is slidably inserted is opened in the injection case portion 1b, and a recess is formed in the lower end portion. 21 is formed, the supply ring 22 and the injection nozzle 5 are attached in the recess 21, and the supply port pipe 6 for supplying conductive ink is attached to the side surface. In the figure, reference numeral 23 is a metal bush, 24 is a metal seal, and 25 is an O-ring.
The connecting arm 2a of the element holder 2 is disposed in the injection case portion 1b, and the injection case portion 1b is provided with coupling engagement surfaces 13a and 13b for connecting the connecting arm 2a and the plunger 4. Correspondingly, a window hole 26 is opened so that the tightening screw 16 can be operated through the window hole 26 (see FIG. 1).

The injection nozzle 5 is composed of a nozzle holder 5a and a nozzle tube 5b fitted therein, and the nozzle holder 5a is fitted into the recess 21 of the injection nozzle 1b together with the supply ring 22 and attached. Although the attachment of the nozzle holder 5a and the supply ring 22 is not shown in the drawings, it is preferable to fasten and fix the nozzle holder 5a and the supply ring 22 to the nozzle tube 5b with screws or screws.
The supply ring 22 forms an opening continuous with the cylinder hole 20 at a central portion thereof to form a liquid reservoir upper chamber 31a which becomes an upper chamber of the liquid reservoir chamber 31, and the nozzle tube 5b has a small diameter predetermined diameter at the tip thereof. The injection hole 30 is opened, and a liquid reservoir chamber 31 is formed in the nozzle holder 5a so as to be interposed between the upper chamber 31a and the injection hole 30. The liquid storage chamber 31 substantially constitutes a liquid storage chamber together with the liquid storage upper chamber 31a.
The cylinder hole 20, the liquid reservoir upper chamber 31a, the liquid reservoir chamber 31, and the injection hole 30 are formed so as to be arranged on the same axis as the axis of the plunger 4, and the tip of the plunger 4 It is made to locate in the liquid reservoir upper chamber 31a. In addition, it is preferable to form a smooth concave surface 32 on the distal end surface of the plunger 4.
The injection hole 30 is a minute hole having the same hole diameter as the minute length, but the liquid reservoir chamber 31 has an upper end that has the same diameter continuous with the liquid reservoir upper chamber 31 a and a diameter from there toward the injection hole 30. Smaller ones are formed sequentially, including a horn shape known as a pressure-increasing shape.

Further, the supply ring 22 forms an introduction path 33 extending in the outer peripheral direction on the bottom surface thereof, the inner end thereof communicates with the liquid reservoir upper chamber 31a, and the outer end supplies the conductive ink connected to the supply port pipe 6. The conductive ink that is communicated with the passage 34 and supplied from the supply port pipe 6 under pressure from an ink tank (not shown) enters the liquid reservoir upper chamber 31 a through the supply passage 34 and the introduction passage 33, and is supplied to and supplied to the liquid reservoir 31. To be.
The introduction path 33 is formed with a weir 33a having a structure in which the passage is narrowed, specifically, a structure in which the passage width is narrowed or the passage height is reduced. The conductive ink in the liquid reservoir chamber 31 is prevented from flowing back to the supply path 34 side.

  Although it does not restrict | limit especially as a conductive ink, In metal size, such as silver (Ag) or copper (Cu) which mixed nano size, submicron size, or those mixed, or the metal fine particle which performed coating processing on them, A metal fine particle dispersion in which a dispersant such as alkylamine or carboxylic acid amine, a binder, a surfactant, or the like is added to a solvent is used. In particular, when drawing a wiring pattern directly, considering that thin lines are thin and effective for multi-layering is possible, the density is higher and the viscosity is several tens to several hundred times that of the conventional inkjet method. It is preferable to use a conductive ink having high viscosity or higher. Of course, it is optional to use a conductive ink for direct drawing proposed in the conventional ink jet method.

Thus, in the droplet ejection device of the present invention, the piezoelectric element 3 is displaced by applying a voltage to the piezoelectric element 3 by the power cord 17, and the plunger 4 is directed toward the liquid reservoir chamber 31 using this as a drive source. To slightly expand and contract. When the plunger 4 is extended, the liquid reservoir chamber 31 is compressed and the conductive ink is pressurized, so that the liquid is ejected from the injection hole 30. When the plunger 4 is contracted, the inside of the liquid reservoir chamber 31 becomes negative pressure. Conductive ink is supplied from the ink tank to the liquid storage chamber 31 through the introduction path 33, and the conductive ink can be ejected as droplets by repeating this operation.
The pressure applied by the plunger 4 to compress the conductive ink in the liquid reservoir chamber 31 by the shape of the liquid reservoir chamber 31 and the concave surface 32 formed on the lower end surface of the plunger 4 in combination with the output of the piezoelectric element 3. Since the pressure is increased, even if the conductive ink has a high viscosity, it can be reliably and smoothly ejected. Further, since the weir 33a is formed in the introduction path 33 of the conductive ink leading to the liquid reservoir chamber 31 so as to prevent the backflow of the conductive ink, the pressure loss during pressurization by the plunger 4 is minimized and the conductive ink is used. Therefore, the ejection of the conductive ink droplet can be further ensured.

  For example, the dimensions of the main part of the droplet ejecting apparatus are exemplified by the outer diameter of the casing 1 being 18 mm, the length being 84 mm, the piezoelectric element 4 being 4.5 mm × 5.2 mm × 41 mm, and the hole diameter of the injection hole 30 being It is 5-100 micrometers (illustration shows 50 micrometers).

Next, another embodiment of the first embodiment will be described.
FIG. 5 shows a configuration in which a diaphragm 40 is disposed on a critical surface between the cylinder hole 20 and the liquid reservoir upper chamber 31a (substantially, the liquid reservoir chamber 31). Specifically, the diaphragm 40 is attached to the upper surface of the supply ring 22 by adhering it, and is tightly held between the upper surface wall of the recess 21 formed in the injection case portion 1b and the lower end surface of the plunger 4 is The diaphragm 40 is brought into contact with the diaphragm 40. Further, an enlarged diameter portion 41 is formed at the lower end portion of the cylinder hole 20 so as to assist the upward bulging of the diaphragm 40.
Further, in FIG. 5, the injection nozzle 5 is configured such that the nozzle holder itself is the nozzle body 5 a ′ without forming the two members of the nozzle holder 5 a and the nozzle tube 5 b, and the liquid storage chamber 31 and the injection hole 30 are formed thereon. The case is shown as an example.
In FIG. 5, in order to avoid duplication of explanation, the same members as those in FIG.

According to the configuration in which the diaphragm 40 is disposed, the upper surface of the liquid reservoir upper chamber 31a is completely sealed, so that the diaphragm 40 is slightly expanded and contracted in conjunction with the minute expansion and contraction movement of the plunger 4, so As the compressive force increases, the airtightness in the liquid storage chamber 31 increases and air does not easily accumulate, and the conductive ink does not touch the sliding surface at the lower end of the plunger 4, so that the plunger 4 can move smoothly and smoothly. Can be maintained over a long period of time, and a seal member such as the metal seal 24 or the O-ring 25 (see FIG. 3) is not required, and the structure can be simplified.
Furthermore, if the outer diameter of the lower end portion where the plunger 4 abuts on the diaphragm 40 is changed, the pressure in the liquid reservoir chamber 31 can be changed. Therefore, by replacing the plunger with a different outer diameter, the ejection amount of the conductive ink is changed. Can be changed.

In the above description, the case where the supply ring 22 is used as a constituent member of the injection nozzle 5 has been exemplified. However, the supply ring 22 may not be used.
6 and 7 illustrate the case where the supply ring 22 is not used, corresponding to the embodiment of FIG. That is, a concave portion 42 into which only the nozzle main body 5a ′ is fitted is formed at the lower end portion of the injection case member 1b, and the nozzle main body 5a ′ is fitted into the concave portion 42 and attached by screwing or screwing (not shown). Introducing passages 43 and 43a corresponding to the introduction passage 33 and the weir 33a are formed on the upper surface of the main body 5a '(see FIG. 7).

FIG. 8 shows an embodiment in which the configuration in which the diaphragm 40 is disposed is further improved as in FIG.
In FIG. 8, reference numeral 44 denotes a magnet plate bonded to the upper surface of the diaphragm 40, and 45 denotes a magnet (permanent magnet) inserted into the lower end of the plunger 4. The magnet 45 is attracted to the upper surface of the magnet plate 44. It is a configuration.
According to the configuration of FIG. 8, since the diaphragm 40 is provided, the same action as in the case of FIG. 5 can be obtained, and the plunger 4 is connected to the diaphragm 40 via the magnet 45 and the magnet plate 44. Therefore, the follow-up performance of the diaphragm 40 with respect to the fine expansion / contraction movement of the plunger 4, particularly the follow-up performance during upward contraction, is excellent, and high-speed injection can be handled.
In FIG. 8, in order to avoid duplication of explanation, the same members as those in FIG.

9 and 10 show an embodiment in which the liquid reservoir chamber 31 leading to the injection hole 30 formed in the nozzle tube 5b is improved.
As shown in the figure, a plurality of guide rims 50 are formed at equal intervals on the inner wall surface forming the liquid storage chamber 31 at regular intervals, which are spirally curved ridges as they go downstream. It is set as the structure arrange | positioned in a spiral shape in view.
As a result, the conductive ink pressure-flowed from the liquid reservoir chamber 31 to the ejection hole 30 is rectified by the guide rims 50 and flows down toward the axis of the ejection hole 30, so that the straightness when the conductive ink is ejected is straight. Can be increased.

11 and 12, a plurality of guide grooves 52 that are spirally curved toward the downstream are formed on the inner wall surface forming the liquid reservoir chamber 31 at equal intervals, and these are spirally formed in a plan view as a whole. The arrangement is arranged. Each guide groove 52 is narrowed toward the upstream side and the downstream side with the substantially middle portion being the maximum width, and the bottom surface of the groove is not a parabolic surface but a conical surface 52a, that is, a linear surface that is successively reduced in diameter. It is said.
Also in this configuration, the conductive ink pressure-flowed from the liquid reservoir 31 to the ejection hole 30 is subjected to the rectifying action by the guide grooves 52, so that the straightness when the conductive ink is ejected can be improved. In the case of the guide groove 52, since the resistance applied to the conductive ink is smaller than that of the guide strip 50, it is effective to ensure straightness with respect to the conductive ink having higher viscosity.

  In the embodiment of FIGS. 9 to 12, the case of the liquid reservoir 31 formed in the nozzle tube 5 b has been described, but the nozzle body 5 ′ (see FIGS. 5 and 7) not using the nozzle tube 5 b is formed. Needless to say, the present invention can also be applied to the liquid storage chamber 31.

Next, a second embodiment of the present invention, specifically, an embodiment in which the overall structure of the casing and the support structure of the piezoelectric element are different will be described with reference to FIGS.
In FIG. 13, the casing 101 has an integral structure without being divided into the drive case portion and the injection case portion as described above, and is configured by assembling the injection nozzle 105 including the nozzle holder 105a and the nozzle tube 105b on the lower end surface thereof. The injection nozzle 105 is detachably attached by a bolt 111.
Further, the casing 101 has a cap portion 101c that is detachably sealed with a bolt 112 at the upper end, and a cylinder hole 120 is opened in the lower portion.

A laminated piezoelectric element 103 is mounted in the casing 101 without using an element holder, and the upper surface of the plunger 104 is brought into direct contact with the lower end of the piezoelectric element 103 so that the piezoelectric element 103 is slightly expanded and contracted. The plunger 104 is arranged to slide in the cylinder hole 120 by the movement.
The piezoelectric element 103 is bonded and fixed to the mounting disk 113 on the upper surface, and is fixed by fastening the mounting disk 113 between the casing 101 and the cap part 101c with the bolt 112, and is fixed to the cap part 101c. The power cord 117 is connected by the attached wiring plug 114.
Further, the adjustment ring 118 is rotatably attached to the outer periphery of the casing 101, specifically, the outer periphery of the mounting disc 113 by screwing, that is, the screws are engaged with each other. The height can be adjusted by moving it up and down within a certain range. A slit 118a is formed in the adjustment ring 118, and the slit 118a is narrowed by the clamp screw 116 to restrict the rotation of the adjustment ring 118, that is, the casing 101 is fixed at the adjusted position.

A supply port pipe 106 for supplying conductive ink to the ejection nozzle 105 is disposed on the outer periphery of the lower part of the casing 101, and a liquid reservoir chamber is formed through a supply path 134 connected to the pipe 106 and an inflow path 133 formed in the diaphragm 140. Conductive ink is supplied to 131.
Reference numeral 115 in FIG. 13 is an elastic member (disc spring) that urges the plunger 104 upward to assist the contraction operation of the piezoelectric element 103, and 123 is a metal bush for sliding the plunger 104, Reference numeral 144 denotes a magnet plate, reference numeral 145 denotes a magnet (permanent magnet), and reference numeral 104 a denotes a plunger tip provided at the tip of the plunger 104.

In the second embodiment, the case where an inflow path 133 leading to the liquid reservoir 131 is formed in the diaphragm 140 is illustrated.
Specifically, as the diaphragm 140, a thin metal plate having high spring properties such as stainless steel and beryllium copper is used, and etching is performed on the thin plate, as shown in FIG. The inflow path 133 is formed by the annular path 133b, and the annular path 133b is formed between the outer periphery of the plunger tip 104a and opens to the upper surface of the liquid reservoir chamber 131.
The bifurcated path 133a causes a collision at the junction when the conductive ink in the liquid reservoir 131 flows backward toward the supply path 134 when the plunger 104 is compressed, thereby backflowing the conductive ink. To prevent.
The illustrated bifurcated path 133a is illustrated as having a symmetrical groove shape. However, the present invention is not limited to this, for example, a curved groove shape in which one is mainly used for inflow and the other is connected in the middle of the inflow side. It is optional to change the groove, such as increasing the groove width on the annular path 133b side and decreasing the groove width sequentially.

Thus, according to the second embodiment, the overall structure including the casing 101 and the injection nozzle 105 is simplified as compared with the first embodiment, and no element holder for piezoelectric elements is used. Easy to manufacture and inexpensive. In addition, since the inflow path 133 is formed in the diaphragm 140, various groove shapes can be efficiently manufactured by etching, and the backflow of the conductive ink is caused by providing the two-way path 133a in the inflow path 133. It can prevent more reliably.
In the second embodiment, it is optional to appropriately change and apply the embodiment described with reference to FIGS. 5 to 12 of the first embodiment, and in the first embodiment, the second embodiment. Of course, the inflow passage 133 having the diaphragm 140 and the bifurcated passage 133a described in the example can be appropriately changed and applied.

  In the above embodiment of the present invention, the case of the conductive ink used in the wiring pattern direct drawing method as the injection liquid has been described. However, other than that, a phosphor material for a display surface such as a CRT or light Various liquid materials and samples such as liquid resists for modeling, liquid samples for analysis in the food and pharmaceutical fields, samples for DNA analysis, etc. can be used as the injection liquid. It is also possible to apply to a high-viscosity fine particle liquid for minute object modeling in which a high-viscosity material of 10,000 to 100,000 mPa · s, for example, a metal, ceramics, resin, or the like is mixed.

DESCRIPTION OF SYMBOLS 1: Casing 1a: Drive case part 1b: Injection | pouring case part 2: Element holder 2a: Connection arm 3: Piezoelectric element 4: Plunger 5: Injection nozzle 5a: Nozzle holder 5a ': Nozzle main body 5b: Nozzle pipe 6: Supply port Pipe 13a: Engagement surface 13b: Engagement surface 15: Elastic part 20: Cylinder hole 22: Supply ring 26: Window hole 30: Injection hole 31: Liquid reservoir chamber 31a: Liquid reservoir upper chamber 33: Introduction channel 33a: Weir 34 : Supply path 40: Diaphragm 43: Introduction path 43a: Weir 44: Magnet plate 45: Magnet 50: Guide strip 52: Guide groove 101: Casing 103: Piezoelectric element 104: Plunger 105: Injection nozzle 105a: Nozzle holder 105b: Nozzle tube 113: Mounting disk 120: Cylinder hole 131: Reservoir chamber 133: Inflow passage 133 : Bifurcated path 133b: annular channel 134: supply path

Claims (9)

  An injection nozzle having a small-diameter injection hole is provided at the tip of the vertical thin casing. A multilayer piezoelectric element is arranged in the casing, and a plunger that uses the piezoelectric element as a drive source is slightly expanded and contracted in the cylinder hole. A liquid reservoir chamber is formed which is movably accommodated and is connected to the injection hole at the tip of the cylinder hole, and a supply passage of a supply port pipe for introducing the injection liquid is connected to the liquid reservoir chamber and supplied from the supply passage. The injected liquid in the liquid reservoir is pressurized by driving the piezoelectric element to be injected from the injection hole of the injection nozzle, and the casing has an injection nozzle at the lower end surface and a cylinder hole at the top. A plunger is slidably disposed in the cylinder hole, and a laminated piezoelectric element having an upper end attached to an attachment member fixed to the casing is disposed in the casing. Wherein the lower end top droplet ejection device with abutting the plunger.   2. The liquid droplet ejecting apparatus according to claim 1, wherein a supply ring is disposed above the ejection nozzle, and an upper chamber of the liquid reservoir chamber is configured by an opening formed at a central portion thereof. A liquid droplet ejecting apparatus comprising an introduction path leading to the upper chamber on the back surface, communicating the introduction path with the supply path for the injection liquid, and further forming a backflow prevention means in the introduction path.   2. The liquid droplet ejection apparatus according to claim 1, wherein an introduction path leading to a liquid reservoir chamber is formed on an upper surface of the injection nozzle without interposing a supply ring above the injection nozzle, and the injection liquid is supplied to the introduction path. A droplet ejecting apparatus characterized in that it communicates with a path, and further, a backflow prevention means is formed in the introduction path.   4. The liquid droplet ejecting apparatus according to claim 2, wherein a diaphragm is provided on a critical surface between the cylinder hole and the liquid reservoir and a connecting member is provided for causing the diaphragm to follow the fine expansion and contraction of the plunger. A droplet ejection device characterized by the above.   5. The droplet ejection apparatus according to claim 4, wherein an introduction path and a backflow prevention means are formed in the diaphragm instead of forming the introduction path on the upper surface of the ejection nozzle.   6. The liquid droplet ejection apparatus according to claim 1, wherein the ejection nozzle has a small-diameter ejection hole at a tip thereof, and the liquid reservoir chamber sequentially decreases in diameter toward the ejection hole. A droplet ejecting apparatus characterized by being formed to be.   7. The liquid droplet ejecting apparatus according to claim 6, wherein a plurality of guide edges or guide grooves are spirally formed in the liquid reservoir.   The injection nozzle is composed of two members, a nozzle holder and a nozzle tube fitted therein, the injection hole is formed at the tip of the nozzle tube, and the liquid reservoir chamber is formed between the nozzle holder and the nozzle tube. The liquid droplet ejection apparatus according to claim 6 or 7, wherein   2. The droplet ejection apparatus according to claim 1, wherein the ejection liquid is a dispersion liquid for drawing a wiring circuit containing metal fine particles.

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