JP2010164502A - Droplet spouting head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost droplet spouting head which can precisely spit or dispense a fine droplet by using a piezoelectric element and which is suitable for being disposable. <P>SOLUTION: In the droplet spouting head 1, a cavity aperture 53 of an elastic cavity plate 50 is sealed by a pressurizing face 63a of a pressure plate 60 and the back plane 47 of a nozzle plate 40, thereby forming a cavity 53A. The cavity 53A is in its compressed state by a preload of a preloading mechanism 6. When the piezoelectric element 5 is made contracted, the preload is temporarily released, and the cavity 53A is expanded; and if the piezoelectric element 5 is brought to extend at a prescribed timing, the cavity 53A of the cavity plate 50 is compressed and varied in a direction in which its internal pressure increases, and a fine droplet is spouted from a nozzle 43, which is communicating with the cavity 53A. Since the compression amount of the cavity 53A is regulated to be a fixed amount by a displacement regulating plate 48, a specific amount of droplets can be spouted correctly at any time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a droplet discharge head that discharges droplets from a nozzle using a piezoelectric element. More specifically, the present invention relates to a droplet discharge head capable of accurately discharging or dispensing a liquid such as a biological material, a reagent, or an adhesive minutely.

  Suction-type pipettes and pressure-type dispensers are used as non-contact dispensing technology for fine droplets in industrial and medical fields, and inkjet heads are widely used in the field of printing as pixel forming technology consisting of fine droplets. It is popular. In recent years, in the dispensing of reagents in the medical field and the application of adhesives in the industrial field, droplet dispensing tools or liquids that can accurately dispense or apply several hundred picoliter to several nanoliter level liquid droplets. There is a need for a drop ejection tool. In order to meet this requirement, it is desirable to use an inkjet head. For example, it is conceivable to use the inkjet head disclosed in Patent Documents 1 and 2. Ink jet heads disclosed in these documents have a configuration in which a deformable layer capable of elastic deformation is formed between a piezoelectric element and an ink cavity.

  Here, when dispensing reagents, specimens, etc., it is desirable to make the dispensing tool disposable in order to prevent such contamination, but in general, the inkjet head is expensive and not suitable for disposable use. In addition, since the piezoelectric element and the like contain harmful substances such as lead, it cannot be discarded as it is.

In view of this, the present applicant has proposed an ink jet type droplet discharge head in Patent Document 3 in which a flow path unit including a nozzle and an ink cavity is detachable from a drive unit including a piezoelectric element. In this droplet discharge head, only an inexpensive flow path unit can be disposable, which is suitable for dispensing reagents and the like.
JP 07-290705 A JP 09-226120 A JP 2008-114569 A

  When an ink jet head of the type disclosed in Patent Documents 1 and 2 is used as a droplet discharge head for dispensing reagents, specimens, and the like, there are the following problems. In other words, the volume of the ink cavity changes due to the change of the elastically deformable deformation layer, which causes ink droplets to be ejected from the ink nozzles. Therefore, if the deformation amount of the deformation layer cannot be managed accurately, the ejected droplets The amount of liquid droplets fluctuates, and it is not possible to accurately discharge micro droplets.

  Further, in order to change the ejection characteristics, for example, the deformation layer may be changed to one having different elastic characteristics. However, since the deformable layer is bonded and fixed to another member, it is not possible to exchange only some of these parts, or it is difficult to exchange, and the whole must be replaced. Many cases are not economical.

  In view of the above, an object of the present invention is to propose a droplet discharge head capable of accurately discharging or dispensing minute droplets by elastically deforming an ink cavity using a piezoelectric element. .

  Another object of the present invention is to propose an inexpensive droplet discharge head suitable for disposable use by facilitating replacement of parts.

In order to solve the above problems, the droplet discharge head of the present invention is
A nozzle plate;
A cavity plate laminated on the nozzle plate;
A pressure plate laminated on the cavity plate so as to sandwich the cavity plate with the nozzle plate;
A displacement regulating member disposed between the nozzle plate and the pressure plate;
A piezoelectric element that pressurizes and displaces the pressure plate in the stacking direction of the nozzle plate, the cavity plate, and the pressure plate;
A preload mechanism that presses the piezoelectric element against the pressure plate and holds the pressure plate, the cavity plate, and the nozzle plate in a pressure contact state;
The cavity plate is made of a material that is elastically deformable in the laminating direction, and an opening for a cavity penetrating in the laminating direction is formed.
The nozzle plate includes a droplet discharge nozzle, a liquid supply path for supplying a liquid to the nozzle, a nozzle plate-side sealing surface for sealing the cavity opening from one side in the stacking direction, A nozzle plate-side contact surface capable of contacting the displacement regulating member from one side in the stacking direction is formed;
The pressure plate includes a pressure plate side sealing surface that seals the cavity opening from the other side in the stacking direction, and a pressure plate that can contact the displacement regulating member from the other side in the stacking direction. Side contact surface is formed,
The cavity plate is compressively deformed in the stacking direction by the preload of the preload mechanism,
The amount of compression of the cavity plate is regulated by contact between the displacement regulating member, the nozzle plate-side contact surface, and the pressure plate-side contact surface.

  In the liquid droplet ejection head of the present invention, a cavity opening is formed in a cavity plate made of an elastic material sandwiched between a nozzle plate and a pressure plate, and the cavity opening is formed on the nozzle plate side sealing surface and the additional surface. A cavity is formed for storing the liquid discharged from the nozzle and sealed by the pressure plate side sealing surface. In addition, the cavity is held in a state of being compressed and deformed in the stacking direction by the preload by the preload mechanism.

  When the piezoelectric element is driven and contracted in the laminating direction, the piezoelectric element retreats from the pressure plate and the preload temporarily decreases, and the cavity expands in the laminating direction due to the elastic restoring force of the cavity plate, and its internal volume Increases and the liquid flows into the cavity via the liquid supply path. When the piezoelectric element is driven in the reverse direction at a predetermined timing and extended in the stacking direction, the pressure plate is pushed out in the stacking direction by the piezoelectric element, the cavity plate is elastically deformed, the cavity is compressed in the stacking direction, and the internal pressure is reduced. It changes in an increasing direction. When the pressure plate and the nozzle plate on both sides of the cavity plate come into contact with the displacement regulating plate disposed therebetween from both sides, the cavity is prevented from being compressed. Due to the change in the internal pressure of the cavity, micro droplets are separated and discharged from the liquid meniscus formed in the nozzle opening. As described above, since the amount of compression of the cavity is regulated to be constant by the displacement regulating member, the amount of compression (exclusion volume) of the cavity during droplet discharge can be made constant, and a constant amount of micro liquid is always obtained. Drops can be discharged accurately.

  Here, the droplet discharge head of the present invention is characterized in that the nozzle plate, the cavity plate, and the pressure plate are separable in the stacking direction and are held in a stacked pressure contact state by the pre-pressure. Yes.

  If the nozzle plate side sealing surface and the pressure plate side sealing surface and the cavity plate side surface to which they are pressed can be sealed in a liquid-tight state by pressing, these three members are simply laminated. Thus, a liquid-tight cavity can be formed simply by making the pressure contact state by the preload by the preload mechanism. Therefore, there is no need to bond or join these three members. Therefore, when dispensing different types of liquids, etc., only these three members need to be replaced. Therefore, the expensive piezoelectric element side can be used as it is, and a droplet discharge head suitable for disposable use can be realized. Further, there is no possibility that the reagent in the cavity is contaminated by the adhesive for joining the three members. Furthermore, since the replacement of each of the three members is simple, it is easy to obtain a droplet discharge head having the required characteristics by changing the combination of the three members. It is economical because it is not necessary to exchange the whole.

  Next, in the droplet discharge head of the present invention, at least one through hole penetrating in the stacking direction may be formed in the cavity plate, and at least one displacement regulating member may be disposed in the through hole.

  In this case, the pressure plate side contact surface and the pressure plate side sealing surface can be the same surface, and the nozzle plate side contact surface and the nozzle plate side sealing surface can be the same surface.

  In this case, the displacement regulating member can be integrally formed on at least one of the nozzle plate side contact surface and the pressure plate side contact surface. It is also possible to form a displacement restricting plate on both sides.

  The preload mechanism may include a biasing member that biases the piezoelectric element against the pressure plate, and an adjustment member for adjusting a biasing force by the biasing member.

  Next, the liquid droplet ejection head of the present invention includes a drive unit and a flow path unit that is detachably attached to the drive unit, and the drive unit includes the piezoelectric element and the preload mechanism. The flow path unit includes the nozzle plate, the cavity plate, the pressure plate, and the displacement regulating member. In this way, if the flow path unit is detachable, the flow path unit can be easily replaced.

  In this case, a holding case that holds the nozzle plate, the cavity plate, and the pressure plate in a stacked state is disposed in the flow path unit, and the holding case is detachable from the drive unit. When the mounting portion mounted at the position is disposed and the flow path unit is mounted on the mounting portion, the displacement surface of the piezoelectric element faces the pressure plate of the flow path unit, and the preload by the preload mechanism is What is necessary is just to enable it to add to the said pressurization board from a displacement surface.

  In the liquid droplet ejection head of the present invention, the compression amount of the cavity is regulated with high accuracy by the contact of the displacement regulating member with the nozzle plate side contact surface and the pressure plate side contact surface. Therefore, it is possible to always discharge a certain amount of minute droplets with high accuracy.

  Further, in the present invention, when the three members of the nozzle plate, the cavity plate, and the pressure plate are held in a laminated state in a separable state, an adhesive or the like for joining them becomes unnecessary, and the cavity is formed by the adhesive. There is no adverse effect such as contamination of the liquid stored inside. In addition, since the replacement work of the three members is simple, it is easy to replace the nozzle plate when nozzle clogging occurs, and it is easy to obtain a head with desired droplet discharge characteristics by changing the combination of the three members. And it can be done inexpensively.

  Furthermore, in the present invention, when the flow path unit including the three members is detachable from the drive unit including the piezoelectric element, only an inexpensive flow path unit can be made disposable. Therefore, a droplet discharge head suitable for use as a disposable dispensing tool for dispensing specimens, reagents, and the like can be obtained.

  Embodiments of a droplet discharge head to which the present invention is applied will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing a droplet discharge head according to the present embodiment, FIG. 2 is a longitudinal sectional view of the droplet discharge head taken along line II-II in FIG. 1, and FIG. It is a perspective view which shows the droplet discharge head in the state which removed the path unit. The droplet discharge head 1 includes a drive unit 2 and a flow path unit 3 that is detachably attached to the drive unit 2.

(Drive unit)
The drive unit 2 includes a unit case 4, a stacked piezoelectric element 5 housed in the unit case 4, and a preload mechanism 6 for preloading the piezoelectric element 5. The unit case 4 includes a pair of end plates 7 and 8 each having an elongated rectangular shape extending in parallel at regular intervals, and a rectangular back plate 9 connecting between the rear ends of the end plates 7 and 8. .

  A holding cylinder 10 having a rectangular cross section is attached between the end plates 7 and 8 of the unit case 4 so as to extend in the front-rear direction. The front end and the rear end of the holding cylinder 10 are respectively formed with a rectangular frame-shaped front flange 10a and a rear flange 10b extending at right angles outward, and the front flange 10a and the rear flange 10b are connected to the end plate 7, 8 is fixed. A rectangular parallelepiped laminated piezoelectric element 5 is accommodated in the holding cylinder 10 in a coaxial state. The displacement direction of the piezoelectric element 5 is the front-rear direction, the rectangular front end displacement surface 5 a is exposed forward from the front end opening 10 c of the holding cylinder 10, and the rectangular rear end face 5 b is also the rear end opening 10 d of the holding cylinder 10. It is exposed from the back.

  Here, the length in the front-rear direction of the piezoelectric element 5 in a non-driven state is slightly longer than that of the holding cylinder 10. Therefore, as can be seen from FIGS. 2 and 3, in a state where the rear end surface 5b coincides with the rear end of the holding cylinder 10, the front end displacement surface 5a slightly protrudes forward from the front end opening 10c. In addition, oblong wiring holes 10e and 10f that are long in the front-rear direction are formed on the left and right side surfaces of the holding cylinder 10, and wirings 11a and 11b for driving the piezoelectric element 5 are disposed through these holes. .

  A preload mechanism 6 for preloading the piezoelectric element 5 forward is attached to the rear side of the piezoelectric element 5 housed in the holding cylinder 10. The preload mechanism 6 includes a slide block 12 disposed between the end plates 7 and 8 so as to be slidable in the front-rear direction. The slide block 12 has slide pins 12a and 12b attached to both ends. The slide pins 12a and 12b are slidable in slide grooves 7a and 8a formed in the end plates 7 and 8 and extending in the front-rear direction. Plugged in. Therefore, the slide block 12 can be slid along the slide grooves 7a and 8a from the position where the slide block 12 contacts the rear end surface 10g of the rear flange 10b of the holding cylinder 10 to the rear side. The rear end face 5b of the piezoelectric element 5 is joined to the front end face of the slide block 12, and the piezoelectric element 5 slides back and forth with the slide block 12 as a whole.

  A leaf spring 13 is disposed on the rear side of the slide block 12 and is bent so as to open forward. The leaf spring 13 is pressed against the front slide block 12 by a preload adjusting screw 14 from the rear side. When the screwing amount of the preload adjusting screw 14 is increased, the leaf spring 13 is crushed in the front-rear direction accordingly, and a larger preload acts on the slide block 12.

  On the other hand, the end plates 7 and 8 of the unit case 4 are provided with front end portions 7b and 8b extending forward from the front end of the holding cylinder 10, and the front ends of these front end portions 7b and 8b approach each other. The mounting guides 7c and 8c bent at right angles to each other are formed. The front end portions 7b and 8b, the mounting guides 7c and 8c, and the front end surface 10h of the holding cylinder 10 form a mounting portion 15 of the flow path unit 3. The flow path unit 3 can be mounted on the mounting portion 15 along the mounting guides 7c and 8c from the left-right direction.

(Flow path unit)
Next, FIG. 4 is an exploded perspective view showing the flow path unit 3 removed from the drive unit 2 in an exploded state. FIG. 5A is a perspective view showing a portion of the flow path unit 3 in a vertical cross section, and FIG. 5B is an exploded perspective view of the flow path unit 3 in the vertical cross sectional state of FIG. With reference to these drawings, the structure of the flow path unit 3 mounted in a detachable state on the mounting portion 15 will be described.

  The flow path unit 3 includes a rectangular dish-shaped holding case 30, and a nozzle plate 40, a cavity plate 50, and a pressure plate 60 having a rectangular outline of the same size are provided in the holding case 30. It is stored in a stacked state in the vertical direction. A pair of left and right guide pins 61, 62 are vertically fixed to the pressure plate 60, and these guide pins 61, 62 are guide holes 41, 42, 51 for positioning formed in the nozzle plate 40 and the cavity plate 50. , 52 in a slidable state. The nozzle plate 40, the cavity plate 50, and the pressure plate 60 are only stacked while being positioned by the guide pins 61 and 62, and are not joined to each other by an adhesive or the like. Therefore, these three members can be easily separated along the stacking direction.

  The holding case 30 includes a rectangular bottom plate portion 31, end plate portions 32 and 33 erected at right angles from both ends of the bottom plate portion 31, and side plates erected at right angles from left and right ends of the bottom plate portion 31. Parts 34 and 35. The bottom plate portion 31 is formed with through holes 31a, 31b at portions facing the guide pins 61, 62, and a long hole 31c is formed between them. Further, the front end portions of the end plate portions 32, 33 on both sides are formed with mounting flanges 32a, 33a bent at a right angle in a direction away from each other. These mounting flanges 32 a and 33 a are set to dimensions that can be inserted along the mounting guides 7 c and 8 c from the side with respect to the mounting portion 15 of the drive unit 2.

  The nozzle plate 40 is a rigid rectangular plate having a certain thickness made of a plastic plate, a metal plate such as stainless steel, a semiconductor substrate, or the like. The nozzle plate 40 is formed with a droplet discharge nozzle 43 penetrating in the thickness direction, and the nozzle opening 43 a is located on the front surface 44 of the nozzle plate 40. The nozzle opening 43 a is exposed forward through the long hole 31 c of the bottom plate portion 31 of the holding case 30. A liquid supply path 45 is formed at a position away from the nozzle 43. The liquid supply path 45 includes a liquid supply hole 45a penetrating the nozzle plate 40 in the thickness direction, and a communication path 45b formed along the front surface 44 of the nozzle plate 40. The communication path 45b includes a front side. The liquid supply pipe 46 is mounted and fixed. The liquid supply pipe 46 protrudes forward from a long hole 31c formed in the bottom plate portion 31 of the holding case 30, and a liquid supply tube (not shown) is connected thereto.

  Here, FIG. 6 is a perspective view showing the nozzle plate 40 and the cavity plate 50 in a stacked state. As can be seen from this figure, four displacement regulating plates 48 are integrally formed on the flat back surface 47 (nozzle plate side blocking surface, nozzle plate side contact surface) of the nozzle plate 40. These displacement regulating plates 48 are plates of a certain length, a certain width, and a certain height that stand vertically from the back surface 47. These displacement restricting plates 48 extend in parallel in the left-right direction and are arranged point-symmetrically.

  Next, the cavity plate 50 and the pressure plate 60 will be described with reference to FIGS. First, the cavity plate 50 is an elastic rectangular plate having a certain thickness made of silicone rubber having elasticity characteristics such as PDMS (polydimethylsiloxane), an elastomer having elasticity, or the like. In the cavity plate 50, an elongated cavity opening 53 extending in the left-right direction is formed in the central portion so as to penetrate in the thickness direction (stacking direction). The cavity opening 53 has one end portion in the left-right direction communicating with the nozzle 43 of the nozzle plate 40, and the other end portion communicating with the liquid supply hole 45a.

  Further, four through holes 54 are formed in the cavity plate 50 so as to surround the cavity opening 53. The through hole 54 in this example is an L-shaped through hole having a constant width, and each through hole 54 extending in the left-right direction has a displacement restriction for each nozzle plate 40 in a state of being stacked on the nozzle plate 40. The plate 48 is inserted with play. Further, the thickness of the nozzle plate 40 is set to be slightly larger than the height of the displacement regulating plate 48.

  The pressure plate 60 loaded on the flat back surface 55 of the cavity plate 50 is a rigid rectangular plate made of a plastic plate, a metal plate such as stainless steel, a semiconductor substrate, or the like. On the front surface 63 of the pressure plate 60, a flat rectangular pressure surface 63a (pressure plate side blocking surface, pressure plate side contact surface) projecting slightly forward is formed at the center portion thereof, and at the four corners thereof. A flat contact surface 63b having the same height is formed. The pressure surface 63 a and the contact surface 63 b are in contact with the flat back surface 55 of the cavity plate 50. The back surface 64 of the pressure plate 60 is a flat surface, and the front end displacement surface 5a of the piezoelectric element 5 of the drive unit 2 is pressed with a predetermined pre-pressure from the rear side.

(Installation of flow path unit and droplet discharge operation)
FIG. 7 is a schematic diagram showing a state before the flow path unit 3 is mounted on the mounting portion 15 of the drive unit 2, and the cavity 53 </ b> A, the through hole 54, and the displacement regulating plate 48 are laterally arranged for easy understanding. Are shown in a line. In the flow path unit 3 before mounting, the central cavity plate 50 made of an elastic material remains at its original thickness t1. The height h of the displacement regulating plate 48 is smaller than the thickness t1. Therefore, the front end surface 48a of the displacement regulating plate 48 of the nozzle plate 40 and the pressure surface 63a (pressure plate side contact surface) of the pressure plate 60 are separated from each other, and a predetermined gap Δt is formed between them. Yes.

  Next, when the flow path unit 3 is mounted, the preload adjusting screw 14 of the preload mechanism 6 of the drive unit 2 is loosened to release the preload on the piezoelectric element 5. As a result, the piezoelectric element 5 can be pushed backward. The front end displacement surface 5a of the piezoelectric element 5 protruding from the mounting portion 15 is retracted rearward, and in this state, the flow path unit 3 can be mounted to the mounting portion 15 from the side as indicated by an arrow in FIG. .

  After the flow path unit 3 is mounted on the mounting portion 15, the preload adjusting screw 14 of the preload mechanism 6 of the drive unit 2 is tightened. As a result, the piezoelectric element 5 is pushed forward as a whole, and the pressure plate 60 of the flow path unit 3 is pushed forward from the rear side by the front end displacement surface 5a to form a state in which a predetermined preload acts.

  FIG. 8A is a schematic diagram showing the flow path unit 3 that is mounted on the mounting portion 15 of the drive unit 2 and applied with a preload. As in the case of FIG. Shown in parallel. As shown in this figure, the pressure plate 60 is pushed forward by the piezoelectric element 5 slightly pushed forward by the preload mechanism 6. As a result, the three members 60, 50, 40 are in a pressure contact state between the front end displacement surface 5a of the piezoelectric element 5 and the mounting guides 7c, 8c of the front end portions 7b, 8b of the end plates 7, 8 of the unit case 4. Then, the cavity plate 50 made of an elastic material is crushed in the stacking direction to the thickness t2. For example, the cavity plate 50 is crushed to a position where the pressure surface 63 a (pressure plate side contact surface) of the pressure plate 60 contacts the tip surface 48 a of the displacement regulating plate 48.

  In this state, the pressure surface 63a (pressure plate side sealing surface) of the pressure plate 60 is pressed in a liquid-tight state on the back surface side of the cavity opening 53, and the back surface 47 (nozzle plate side sealing) of the nozzle plate 40 on the front surface side. The surface) is in pressure-contact with the liquid-tight state, so that the front and back of the cavity opening 53 are surely sealed to form a liquid storage cavity 53A. After the mounting state is formed, the liquid supply tube 49 for supplying the liquid into the cavity 53A is connected, and the cavity 53A is filled with the liquid.

  As shown in FIG. 8B, when the piezoelectric element 5 is driven and contracted in the front-rear direction (stacking direction) after filling with the liquid, the front end displacement surface 5a of the piezoelectric element 5 moves backward from the pressure plate 60 and preloads. Decreases temporarily. As a result, the cavity 53 </ b> A expands in the stacking direction due to the elastic restoring force of the cavity plate 50, the inner volume thereof increases, and the liquid flows into the cavity 53 </ b> A via the liquid supply path 45.

  Thereafter, as shown in FIG. 8C, when the piezoelectric element 5 is driven in the reverse direction at a predetermined timing and extended in the stacking direction, the pressure plate 60 is pushed forward by the piezoelectric element 5 in the stacking direction. As a result, the cavity plate 50 is crushed and the cavities 53A are compressed in the stacking direction so that the internal pressure increases. Here, the cavity plate 50 is compressed until the pressurizing surface 63a of the pressurizing plate 60 contacts the tip end surface 48a of the displacement regulating plate 48 on the nozzle plate side, and the internal pressure of the cavity due to the pressurizing surface 63a hitting the displacement regulating plate 48 The fine liquid droplet d is separated from the liquid meniscus formed in the nozzle opening 43a and ejected forward.

  In this way, the amount of compression of the cavity 53A is regulated to be constant by the displacement regulating plate 48. Accordingly, the volume reduction amount of the cavity 53A when droplets are discharged can always be made constant, so that a constant amount of minute droplets can always be accurately discharged.

  Further, the amount of displacement of the piezoelectric element 5 can be controlled by adjusting the preload by the preload mechanism 6 that preloads the piezoelectric element 5. For example, if the preload is reduced, the piezoelectric element 5 extends backward against the preload when the piezoelectric element 5 extends, so that the amount of movement of the pressure plate 60 pushed out by the front end displacement surface 5a decreases. . As a result, the amount of compression of the cavity plate 50 made of an elastic material is reduced, and the excluded volume of the cavity 53A at the time of compression is reduced, so that the amount of droplets discharged from the nozzle 43 can be reduced. Therefore, the droplet discharge amount can be mechanically changed without changing the drive waveform.

  In addition, as the droplet ejection drive mode by the piezoelectric element 5, the mode called the strike mode and the mode called the push mode are known in the field of the inkjet head. Also in the droplet discharge head 1 of this example, the droplets can be discharged in any mode by adjusting the expansion timing after the piezoelectric element 5 contracts. In the pushing mode, the expansion of the piezoelectric element 5 may be started at a timing after the time required for the pressure fluctuation in the cavity 53A to converge after the piezoelectric element 5 contracts. In this case, the piezoelectric element may be extended at a shorter time interval than in the pushing mode. The pulling mode can discharge a smaller amount of liquid droplets than the pushing mode.

(Function and effect)
As described above, in the droplet discharge head 1, the displacement regulating plate 48 regulates the compression amount of the cavity plate 50 made of an elastic material, that is, the compression amount of the cavity 53A. Therefore, since the excluded volume of the cavity 53A due to the displacement of the piezoelectric element 5 can always be kept constant, variations in the droplet discharge amount can be suppressed.

  In addition, the flow path unit 3 is detachably attached to the drive unit 2 including the piezoelectric element 5. Therefore, when the droplet discharge head 1 is used as a dispensing head for a sample or the like, different types of samples or the like can be dispensed by replacing only the flow path unit 3. Further, since only the used inexpensive flow path unit 3 has to be discarded, it is suitable for use as a disposable dispensing head or the like.

  Further, the cavity plate 50 uses an elastic plate made of PDMS (polydimethylsiloxane), and a cavity 53A sealed in a liquid-tight state is formed by pressure contact with the nozzle plate 40 and the pressure plate 60. Therefore, there is no need to bond and bond the three stacked members to each other, so that the liquid in the cavity 53A is not contaminated by an adhesive or the like.

  Since the joining of the three members is unnecessary, it is convenient because various droplet discharge heads having different characteristics can be easily obtained by appropriately combining the members as necessary. In addition, since there is no need for adhesion and bonding, there is an advantage that the degree of freedom in selecting the materials used for the three members is increased because there is no need to consider adhesiveness due to the adhesive.

  The droplet discharge head 1 can be used for dispensing a specimen such as blood, applying or dispensing a liquid such as an adhesive that clogs in a short time, or a three-dimensional modeling work of a cell. .

  In the above embodiment, the displacement restricting plate 48 is integrally formed on the back surface 47 of the nozzle plate 40. However, the displacement restricting plate 48 may be integrally formed on the pressure surface 63a of the pressure plate 60. is there. In this case, the amount of compression of the cavity plate 50 is restricted by the displacement restricting plate 48 coming into contact with the back surface 47 (nozzle plate side contact surface) of the nozzle plate 40. It is possible to integrally form both the nozzle plate 40 and the pressure plate 60, and the displacement regulating plate 48 is manufactured as a separate member from the nozzle plate 40 and the pressure plate 60 and formed on the cavity plate 50. It is also possible to arrange in the through hole 54 formed. In this case, the back surface 47 (nozzle member side contact surface) of the nozzle plate 40 and the pressure surface 63a (pressure member side contact surface) of the pressure plate 60 abut on the displacement regulating plate 48 from the stacking direction. The amount of compression of the cavity 53A is regulated.

  Next, the surface of the cavity plate 50 made of an elastic material, the pressure surface 63a of the pressure plate 60 in pressure contact with the cavity plate 50, and the back surface 47 of the nozzle plate 40 are subjected to surface treatment so as to ensure sealing performance. Also good. In addition, surface treatment such as water repellent processing or hydrophilic processing may be performed on the inner peripheral surface of the cavity opening 53 of the cavity plate 50 in an appropriate place so that desired droplet discharge characteristics can be obtained.

It is a perspective view of a droplet discharge head to which the present invention is applied. It is a longitudinal cross-sectional view of the droplet discharge head of FIG. It is a disassembled perspective view which shows the droplet discharge head of FIG. 1 in the state which removed the flow path unit. FIG. 4 is an exploded perspective view showing a state in which a flow path unit of the droplet discharge head of FIG. 3 is disassembled. FIG. 2 is a partial perspective view showing the flow path unit of the droplet discharge head of FIG. 1 in a vertical cross-sectional state, and an exploded perspective view thereof. It is a perspective view which takes out and shows the nozzle plate and cavity plate of a flow path unit. FIG. 2 is an explanatory diagram illustrating a state before and after mounting of a flow path unit of the droplet discharge head of FIG. 1. FIG. 2 is an explanatory diagram showing an operation of the droplet discharge head of FIG.

DESCRIPTION OF SYMBOLS 1 Droplet discharge head, 2 Drive unit, 3 Flow path unit, 4 Unit case, 5 Piezoelectric element, 5a Front end displacement surface, 5b Rear end surface, 6 Preload mechanism, 7, 8 End plate, 7a, 8a Slide groove, 7b, 8b Front end, 7c, 8c Mounting guide, 9 Back plate, 10 Holding cylinder, 10a Front flange, 10b Rear flange, 10c Front end opening, 10d Rear end opening, 10e, 10f Wiring hole, 10g Rear end surface, 10h Front end surface, 11a , 11b Wiring, 12 Slide block, 12a, 12b Slide pin, 13 Leaf spring, 14 Preload adjusting screw, 15 Mounting part, 30 Holding case, 31 Bottom plate part, 31a, 31b Through hole, 31c Long hole, 32, 33 End plate Part, 32a, 33a Mounting flange, 34, 35 Side plate part, 40 Nozzle plate, 41, 42 Guide hole, 43 Nozzle, 43a Nozzle opening, 44 Front face, 45 Liquid supply path, 45a Liquid supply hole, 45b Communication path, 46 Liquid supply pipe, 47 Back face, 48 Displacement restricting plate, 48a Tip face, 49 Liquid supply tube, 50 Cavity plate, 51 , 52 Guide hole, 53 cavity opening, 53A cavity, 54 through hole, 55 back surface, 60 pressure plate, 61, 62 guide pin, 63 front surface, 63a pressure surface, 63b contact surface, 64 back surface, t1 of cavity plate Original thickness, thickness of t2 compressed cavity plate, h height of displacement regulating plate, Δt clearance

Claims (8)

A nozzle plate;
A cavity plate laminated on the nozzle plate;
A pressure plate laminated on the cavity plate so as to sandwich the cavity plate with the nozzle plate;
A displacement regulating member disposed between the nozzle plate and the pressure plate;
A piezoelectric element that pressurizes and displaces the pressure plate in the stacking direction of the nozzle plate, the cavity plate, and the pressure plate;
A preload mechanism that presses the piezoelectric element against the pressure plate and holds the pressure plate, the cavity plate, and the nozzle plate in a pressure contact state;
The cavity plate is made of a material that is elastically deformable in the laminating direction, and an opening for a cavity penetrating in the laminating direction is formed.
The nozzle plate includes a droplet discharge nozzle, a liquid supply path for supplying a liquid to the nozzle, a nozzle plate-side sealing surface for sealing the cavity opening from one side in the stacking direction, A nozzle plate-side contact surface capable of contacting the displacement regulating member from one side in the stacking direction is formed;
The pressure plate includes a pressure plate side sealing surface that seals the cavity opening from the other side in the stacking direction, and a pressure plate that can contact the displacement regulating member from the other side in the stacking direction. Side contact surface is formed,
The cavity plate is compressively deformed in the stacking direction by the preload of the preload mechanism,
The liquid droplet ejection head according to claim 1, wherein the amount of compression of the cavity plate is regulated by contact between the displacement regulating member, the nozzle plate-side contact surface, and the pressure plate-side contact surface. The droplet discharge head according to claim 1,
The droplet ejection head, wherein the nozzle plate, the cavity plate, and the pressure plate are separable in the laminating direction and are held in a laminating pressure contact state by the pre-pressure. The droplet discharge head according to claim 1 or 2,
The cavity plate includes at least one through hole penetrating in the stacking direction,
At least one displacement restricting member is disposed in the through hole. The droplet discharge head according to claim 3,
The pressure plate side contact surface and the pressure plate side sealing surface are the same surface,
The droplet ejection head, wherein the nozzle plate side contact surface and the nozzle plate side sealing surface are the same surface. The droplet discharge head according to claim 4,
The liquid droplet ejection head, wherein the displacement regulating member is integrally formed on at least one of the nozzle plate side contact surface and the pressure plate side contact surface. In the liquid droplet ejection head according to any one of claims 1 to 5,
The preload mechanism includes a biasing member that biases the piezoelectric element against the pressure plate, and an adjustment member for adjusting a biasing force by the biasing member. head. In the droplet discharge head according to any one of claims 1 to 6,
A drive unit;
A flow path unit mounted in a removable state on the drive unit;
The drive unit includes the piezoelectric element and the preload mechanism,
The liquid droplet ejection head, wherein the flow path unit includes the nozzle plate, the cavity plate, the pressure plate, and the displacement regulating member. In the droplet discharge head according to claim 7,
The flow path unit includes a holding case that holds the nozzle plate, the cavity plate, and the pressure plate in a stacked state,
The drive unit includes a mounting portion that is mounted in a state where the holding case is detachable,
In a state where the flow path unit is mounted on the mounting portion, the displacement surface of the piezoelectric element faces the pressure plate of the flow path unit, and the preload by the preload mechanism is applied to the pressure plate via the piezoelectric element. A droplet discharge head, which is in a state where it can be added to the liquid.

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