JP2007057436A - Liquid droplet discharge head and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet discharge head capable of suppressing the liquid leak from a nozzle orifice by a simpler configuration. <P>SOLUTION: The liquid droplet discharge head (10) is used in order to discharge a liquid becoming a discharge target as liquid droplets and includes a compartment (20) having a plurality of liquid housing chambers (22) for housing the liquid, a nozzle element (20) having a plurality of nozzle orifices (26) provided so as to respectively communicate with the liquid housing chambers, a plurality of the pressure means provided to the respective liquid housing chambers in a relation of 1:1 in order to pressurize the liquid, a storage member (50) having a plurality of liquid storage chambers (16) provided in a relation of 1:1 with respect to the respective liquid housing chambers in order to supply the liquid and a plurality of the liquid holding means (18) constituted so as to contain porous members and provided in the respective liquid storage chambers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge device including the droplet discharge head for discharging a desired liquid into droplets.

  In recent years, a method for detecting and measuring a target substance in a sample by using a so-called microarray in which a biological substance such as nucleic acid, protein, or cell is immobilized on a substrate as a probe, and utilizing the specificity of binding between biomolecules Is widely used. In order to manufacture such a microarray with high efficiency, a method using a droplet discharge device has been researched and developed.

  In general, biological materials such as nucleic acids used as probes are often obtained only in small amounts, and are very expensive. For this reason, in the case of using a droplet discharge device, there is a technical problem that it is desired to avoid as much as possible the waste of biological material due to liquid leakage from the nozzle hole. Further, such a problem is not limited to a droplet discharge device used for manufacturing a microarray. For example, even in the case of a droplet discharge device used for printing, the same problem as described above may occur when expensive ink is used to perform high-quality printing.

  In response to such a problem, Japanese Unexamined Patent Application Publication No. 2004-160368 (Patent Document 1) discloses a capillary phenomenon by using means such as a bundle of a plurality of capillaries as a tank for storing a liquid containing a biological substance. A technique for generating a negative pressure in a tank using the above is disclosed. According to such a technique, a force for retaining the liquid is generated in the tank communicating with the nozzle hole, so that liquid leakage from the nozzle hole can be suppressed.

  However, when a droplet discharge head having a large number of nozzles and a large number of tanks corresponding to the nozzles is constructed, it is necessary to introduce a liquid holding means composed of a bundle of capillaries disclosed in Patent Document 1 in terms of manufacturing cost. It is considered difficult from the viewpoint of the above. For example, high processing accuracy is required to load a bundle of capillaries into each of a large number of tanks without gaps. Therefore, a technique capable of generating a negative pressure in the tank with a simpler configuration and suppressing liquid leakage from the nozzle hole has been desired.

JP 2004-160368 A

  Therefore, an object of the present invention is to provide a droplet discharge head and a droplet discharge device that can suppress liquid leakage from a nozzle hole with a simpler configuration.

  A first aspect of the present invention is a droplet discharge head that is mounted on a droplet discharge device or the like and is used to discharge a liquid to be discharged as droplets, and includes a plurality of liquid discharge heads for containing the liquid. A container having a liquid storage chamber, a nozzle body having a plurality of nozzle holes provided to communicate with each of the liquid storage chambers, and each of the liquid storage chambers to pressurize the liquid. A plurality of pressurizing means provided, a storage body having a plurality of liquid storage chambers provided one-on-one with each of the liquid storage chambers for supplying the liquid, and a porous body, And a plurality of liquid holding means provided inside each of the storage chambers. Here, the “porous body” is a general term for a solid having a large number of pores therein, and is also called a porous body, a porous solid, or a porous material.

  In such a configuration, by providing liquid holding means made of a porous body inside each liquid storage chamber, an action (that is, negative pressure) for holding the liquid to be discharged is generated, and the nozzle hole is utilized using the action. The liquid leakage from the is suppressed. Specifically, the action of retaining the liquid in place can be obtained by utilizing the interfacial action such as the surface tension and the current state of the capillary in the numerous pores of the porous body. Therefore, it is possible to provide a droplet discharge head that can suppress liquid leakage from the nozzle hole with a simpler configuration.

  Preferably, the liquid holding means is a dense collection of a plurality of microspheres.

  In this case, for example, a method of loading an appropriate amount of microspheres into each liquid storage chamber, or a method in which a large number of microspheres are shaped and fixed in advance and prepared in advance, It is possible to provide the liquid holding means without gaps in each liquid storage chamber by a relatively simple method such as a method of loading.

  Preferably, the microsphere is a glass sphere.

  This is convenient when it is desired to avoid the influence of the outside world as much as possible, for example, when a biological molecule is contained in the liquid to be ejected.

  Further, the liquid holding means may be a sponge body (for example, PVA sponge or the like).

  A suitable liquid holding means can also be obtained by using a sponge body.

  Further, the liquid holding means is preferably provided with a volume smaller than the total volume of the liquid storage chamber so that an excess space in which the liquid holding means does not exist is secured in the liquid storage chamber.

  This makes it possible to more effectively clean the liquid storage chamber, the liquid storage chamber, and the like. In other words, the extra space is secured in each liquid storage chamber, so that more cleaning liquid can be supplied into the liquid storage chamber. Accordingly, it is possible to perform the cleaning process while diluting the liquid to be discarded remaining in the liquid storage chamber at the time of cleaning to a lower concentration, and thus it is possible to suppress the adhesion of the liquid.

  Preferably, the liquid holding means has a film that suppresses the adhesion of the liquid.

  Thereby, clogging of a porous body can be suppressed.

  The coating is preferably made of a polymer comprising 2-methacryloyloxyethyl phosphorylcholine units or a copolymer containing the polymer.

  According to this, it is particularly convenient when the liquid to be ejected contains biological molecules.

  According to a second aspect of the present invention, there is provided a liquid droplet ejection head according to the first aspect of the present invention, a driving means for supporting the liquid droplet ejection head and moving it freely in at least one direction, and the liquid droplet ejection head. And a table that supports an object onto which the droplets discharged from the apparatus are dropped.

  According to such a configuration, it is possible to provide a droplet discharge device that can suppress liquid leakage from the nozzle hole with a simpler configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, a droplet ejection head according to an embodiment to which the present invention is applied and a microarray manufacturing apparatus as an example of a droplet ejection apparatus configured to include the droplet ejection head will be described.

  FIG. 1 is a schematic perspective view for explaining the configuration of a microarray manufacturing apparatus according to an embodiment to which the present invention is applied. The microarray manufacturing apparatus 200 shown in FIG. 1 manufactures a microarray by making a sample solution containing a biological substance (liquid to be discharged) into droplets and discharging the liquid onto a substrate 202 such as a glass substrate as an object. belongs to. As illustrated, the microarray manufacturing apparatus 200 includes, as main components, a table 204 configured to be able to place a plurality of substrates 202, a fixing unit 212 for fixing the droplet discharge head 10, and a table 204. An X-direction drive shaft 214 for freely moving in the X direction, a Y-direction drive shaft 216 for freely moving the droplet discharge head 10 in the Y direction, and a fixing means 212 for freely moving in the Z direction. Z-direction drive shaft 218. Furthermore, the microarray manufacturing apparatus 200 of this example includes a decompression chamber A in which the droplet discharge head 10 is housed and sealed, and the inside can be decompressed, in the base 220. In the microarray manufacturing apparatus 200, the droplet discharge head 10 is moved relative to the substrate 202 by appropriately operating the X-direction drive shaft 214, the Y-direction drive shaft 216, and the Z-direction drive shaft 218. A microarray is produced by discharging a suitable amount of sample solution to a suitable position above.

  FIG. 2 is a cross-sectional view for explaining the structure of the droplet discharge head 10. FIG. 3 is a schematic perspective view of the droplet discharge head 10. 2 corresponds to the section taken along the line II-II shown in FIG. FIG. 4 is a plan view for explaining the structure of each substrate, which is a constituent element of the droplet discharge head 10. Hereinafter, the detailed configuration of the droplet discharge head 10 will be described with reference to the drawings.

  As shown in FIG. 2, the droplet discharge head 10 is configured by laminating substrates 30, 40, and 50, and a nozzle hole 26, a pressurizing chamber 22, and the like are provided at substantially the center of the nozzle hole forming surface 12. The formed head chip 20 is attached. Each reservoir (liquid storage chamber) 16 includes a plurality of through holes provided in the substrate (reservoir) 50. The liquid supplied to each reservoir 16 reaches each pressurizing chamber (liquid storage chamber) 22 through the flow path 13, is pressurized by a pressurizing means (details will be described later), and is discharged from the nozzle hole 26. . The nozzle hole forming surface 12 is the lower surface of the substrate 30 in the drawing. Each reservoir 16 is provided with a liquid holding means 18 made of a porous material.

  As shown in FIG. 3, the droplet discharge head 10 is provided with 96 reservoirs 16 in 8 rows × 12 columns. Liquid to be ejected is supplied from the openings of the respective reservoirs 16 arranged on the surface 14. For example, by providing the reservoirs 16 according to the number and arrangement of wells of a commonly used microtiter plate, liquid can be supplied from the microtiter plate to each reservoir 16 using a dispenser or the like. Further, the surface (the lower surface in the drawing) facing the surface 14 is the nozzle hole forming surface 12, and the nozzle hole 26 is provided at the center (see FIG. 2).

  Next, the structure of each of the substrates 30, 40 and 50 will be described with reference to FIG. As shown in FIG. 4A, the substrate 30 is formed with a plurality (96 in this example) of grooves 13 ′ for forming the flow path 13 together with one surface of the substrate 40. Each groove 13 ′ converges from the periphery of the substrate 30 toward the center, and the end of each groove 13 ′ on the substrate periphery side coincides with the pitch (formation interval) of the reservoir 16. Further, a through hole communicating with each groove 13 ′ is provided at the end of each groove 13 ′ on the substrate center side. As shown in FIG. 4B, 96 through holes 42 are formed in the substrate 40 in 8 rows × 12 columns. The pitch of the through holes 42 matches the pitch of the reservoir 16. The through hole 42 serves as a flow path that allows the flow path 13 and the reservoir 16 to communicate with each other. As shown in FIG. 4C, the substrate 50 has 96 through holes 52 formed in 8 rows × 12 columns. By laminating the substrate 50 on the substrate 40, one opening of the through hole 52 is covered with one surface of the substrate 40, and the reservoir 16 is configured. Each board | substrate 30,40,50 can be formed with materials, such as glass and resin, and a groove | channel and a through-hole can be formed by methods suitable for material, such as an etching and injection molding. After the substrates 30, 40, and 50 are stacked and bonded by a method using thermal welding or an adhesive, the head chip 20 is bonded to the center of the substrate 30, thereby completing the droplet discharge head 10.

  FIG. 5 is a cross-sectional view illustrating the detailed structure of the head chip 20. The head chip 20 is configured to be able to discharge droplets from the nozzle holes by operating the pressurizing means of the pressurizing chamber alone by simply being electrically connected. FIG. 5 shows a cross-sectional view of an electrostatic drive type head chip as an example of the head chip 20. For convenience of explanation, the substrates 40 and 50 are omitted, and only the substrate 30 is shown.

  As shown in FIG. 5, the head chip 20 includes an electrode substrate 121 on which an electrode 108 is formed, a pressurizing chamber substrate (container) 122 for forming the pressurizing chamber 22, and a nozzle substrate on which a nozzle hole 26 is formed. (Nozzle body) 123 is laminated. The pressurizing chamber 22 and the nozzle holes 26 are provided in the same number as the reservoir 16 and correspond to each other one to one. Each pressurizing chamber 22 accommodates a liquid to be ejected supplied through a flow path 13 from a plurality of reservoirs 16 provided one-on-one. Each nozzle hole 26 is provided so as to communicate with each pressure chamber 22. When a voltage is applied between the common electrode (not shown) and the electrode 108, the liquid flowing into the pressurizing chamber 22 is pressurized by the elastic displacement of the vibration plate 109 and is discharged from the nozzle hole 26. Note that a groove is formed in the electrode substrate 121 from the lower surface in the drawing, and the electrode 108 is formed on the ceiling portion thereof. Therefore, a slight gap (air gap) is formed between the electrode 108 and the diaphragm 109. ) Is formed. In the present embodiment, the electrode 108 and the diaphragm 109 correspond to a pressurizing unit, and each pressurizing unit is provided one-on-one with each of the pressurizing chambers 22. The material constituting each of the electrode substrate 121, the pressurization chamber substrate 122, and the nozzle substrate 123 is not particularly limited, but glass, silicon, or the like is suitable when the liquid to be discharged includes a biological sample. By bonding the head chip 20 to the substrate 30, the through holes provided in the electrode substrate 121 and the pressurizing chamber substrate 122 communicate with the through holes of the substrate 30, and the reservoir (not shown) and the pressurizing chamber 22 communicate with each other. Then, the droplet discharge head 10 is completed. In the present embodiment, there is a slight step between the surface of the head chip on which the nozzles are formed and the lower surface of the substrate 30, but both are collectively referred to as the nozzle hole forming surface 12. .

  Here, the liquid holding means 18 will be described in more detail. As the liquid holding means 18, for example, one in which a large number of microspheres having a particle diameter of about 0.5 mm to 1.0 mm are densely used can be used. In this case, a large number of pores are formed between the microspheres, and the whole can be regarded as a porous body. These many holes provide an effect of holding (fastening) the liquid to be discharged. The constituent material of each microsphere can be selected as appropriate. For example, when the liquid to be ejected includes biological molecules as in the present embodiment, each microsphere is preferably a glass sphere (glass bead). As a method of forming such a liquid holding means 18, for example, a method of loading an appropriate amount of microspheres into each reservoir 16 can be considered. According to this method, it is easy to provide the liquid holding means 18 without any gap in the reservoir 16. Further, a glass filter having innumerable fine holes may be used as the liquid holding means 18. In this case, after processing the shape of the glass filter in accordance with the inner diameter of the reservoir 16, the processed glass filter may be loaded into each reservoir 16. Note that a sponge body such as a PVA sponge may be used as the liquid holding means 18.

  Further, as shown in FIG. 2, each liquid holding means 18 has a volume smaller than the total volume of each reservoir 16 so as to secure an extra space in which each liquid holding means 18 does not exist. It is preferable to be provided. In the present embodiment, each liquid holding means 18 is disposed on the bottom side (lower side in the drawing) of each reservoir 16 so as to have a volume that occupies half of the total volume of each reservoir 16. As described above, by securing an excess space in each reservoir 16, cleaning of each reservoir 16 of the droplet discharge head 10 is facilitated. The cleaning method will be described in detail later.

  It is also preferable that each liquid holding means 18 is provided with a coating that suppresses the adsorption of the liquid to be ejected. The constituent material of such a film can be appropriately selected according to the properties of the liquid to be ejected. For example, when the liquid to be ejected contains biological molecules as in the present embodiment, the coating is formed using a polymer comprising 2-methacryloyloxyethyl phosphorylcholine (MPC) units or a copolymer containing the polymer. Good. Such a film can be formed as follows, for example. A copolymer having a ratio of MPC and n-butyl methacrylate (BMA) of 7: 3 is dissolved in ethanol to prepare a 0.1% ethanol solution. Next, this 0.1% MPC-BMA ethanol solution is poured into each reservoir 16, primed, and left for about 1 minute. Thereafter, the ethanol solution is removed by suction from the nozzle hole 26 side and dried at 60 ° C. for about 1 hour. According to this method, a film is formed on each of the liquid holding means 18, and at the same time, a film is formed on the reservoir 16, the flow path 13, and the pressurizing chamber 22. Adhesion and clogging can be suppressed. It should be noted that the liquid holding means 18 to which MPC coating has been applied in advance may be loaded in each reservoir 16.

  FIG. 6 is a cross-sectional view illustrating a method for cleaning each reservoir 16 of the droplet discharge head 10. Note that the same components as those in the droplet discharge head 10 shown in FIG. 2 described above are denoted by the same reference numerals, and detailed description thereof is omitted. After injecting a liquid to be discharged into each reservoir 16 and performing a droplet discharge operation, it is necessary to remove the remaining liquid and clean the interior of the droplet discharge head 10. Specifically, first, the cleaning liquid 60 is supplied to each reservoir 16. Then, by sucking the supplied cleaning liquid 60 from the nozzle hole 26 side, each reservoir 16, each flow path 13, each pressurizing chamber 22, and the like are cleaned. This series of processing is performed a plurality of times as necessary. In the present embodiment, the surplus space is secured in each reservoir 16, so that more cleaning liquid 60 can be supplied into each reservoir 16. In general, the higher the concentration of a sample solution containing biological molecules such as proteins, the easier it will adhere to the reservoir 16 or the like. However, in the droplet discharge head 10 of this embodiment, the sample solution is diluted to a lower concentration. Since the cleaning process can be performed, the adhesion of the sample solution can be suppressed.

  As described above, in this embodiment, the liquid holding means made of a porous body is provided inside each reservoir, thereby holding (fastening) the liquid to be discharged, that is, generating a negative pressure, Utilizing this, liquid leakage from the nozzle holes is suppressed. Therefore, a liquid droplet ejection head and a liquid droplet ejection device (microarray manufacturing) that can suppress liquid leakage from the nozzle holes can be obtained with a simpler configuration.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously.

  For example, the configuration of the droplet discharge head includes a nozzle hole that discharges droplets, a pressurization chamber that includes a pressurizing unit for pressurizing liquid, and a reservoir (liquid reservoir) that communicates with the pressurization chamber through a flow path. The substrate 30, 40, and 50 are not laminated, but may be integrally formed by injection molding or the like. Further, the number and arrangement of the liquid storage units are not limited and can be changed according to the purpose. The pressurizing means may be any system such as an electrostatic driving system or a piezoelectric driving system.

  In the above-described embodiment, a microarray manufacturing apparatus has been described as an example of a droplet discharge apparatus including the droplet discharge head according to the present invention. However, the present invention is a droplet discharge apparatus (so-called inkjet) used for printing applications. The present invention can be widely applied to printers).

It is a schematic perspective view for demonstrating the structure of a microarray manufacturing apparatus. It is sectional drawing for demonstrating the structure of a droplet discharge head. It is a schematic perspective view of a droplet discharge head. It is a top view for demonstrating the structure of each board | substrate which is a component of a droplet discharge head. It is sectional drawing explaining the detailed structure of a head chip. It is sectional drawing explaining the washing | cleaning method of each reservoir of a droplet discharge head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Droplet discharge head, 12 ... Nozzle hole formation surface, 13 ... Flow path, 16 ... Reservoir, 18 ... Liquid holding means, 20 ... Head chip, 22 ... Pressure chamber, 26 ... Nozzle hole, 30, 40, 50 ... Substrate, 42, 52 ... Through hole, 108 ... Electrode, 109 ... Diaphragm, 121, 122, 123 ... Substrate, 200 ... Microarray manufacturing apparatus

Claims (8)

A droplet discharge head used to discharge a liquid to be discharged as droplets,
A container having a plurality of liquid storage chambers for storing the liquid;
A nozzle body having a plurality of nozzle holes provided to communicate with each of the liquid storage chambers;
A plurality of pressurizing means provided one-on-one with each of the liquid storage chambers to pressurize the liquid;
A reservoir having a plurality of liquid storage chambers provided one-on-one with each of the liquid storage chambers to supply the liquid;
A plurality of liquid holding means configured to include a porous body and provided in each of the liquid storage chambers;
A liquid droplet ejection head comprising:   The liquid droplet discharge head according to claim 1, wherein the liquid holding unit is formed by densely arranging a plurality of microspheres.   The liquid droplet ejection head according to claim 2, wherein the microsphere is a glass sphere.   The droplet discharge head according to claim 1, wherein the liquid holding unit is a sponge body.   2. The liquid according to claim 1, wherein the liquid holding unit is provided with a volume smaller than a total volume of the liquid storage chamber so that an excess space in which the liquid holding unit does not exist is secured in the liquid storage chamber. Drop ejection head.   The droplet discharge head according to claim 1, wherein the liquid holding unit has a film that suppresses the adhesion of the liquid.   The droplet discharge head according to claim 6, wherein the coating is made of a polymer composed of 2-methacryloyloxyethyl phosphorylcholine units or a copolymer containing the polymer. A droplet discharge head according to any one of claims 1 to 7;
Driving means for supporting the droplet discharge head and moving it freely in at least one direction;
A table that supports an object to which the droplets discharged from the droplet discharge head are dropped; and
A droplet discharge device.

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