Liquid dispensing device

Abstract

To improve discharge characteristics. [Solution] The housing 2 of the liquid discharge device 1 has a liquid chamber 20 for storing liquid 50 containing particles, and a supply passage 21 for supplying liquid 50 into the liquid chamber 20 via a supply port 21A provided in the liquid chamber 20. The plunger 4 is provided so that the end face 4A on the nozzle 31 side in the reciprocating direction of the plunger 4 is capable of reciprocating within the liquid chamber 20 along the reciprocating direction between a first position S1 in the reciprocating direction within the liquid chamber 20 and a second position S1 on the nozzle 31 side of the first position S1 and the supply port 21A in the reciprocating direction within the liquid chamber 20. The first gap G1 in the intersecting direction between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20, which intersects the reciprocating direction, is larger than the particle diameter of the particles and is no more than twice the particle diameter. The nozzle plate 3 has a tapered portion TP with the nozzle 31 as the apex and which widens in diameter in the direction away from the nozzle 31 along the reciprocating direction.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection apparatus.

Background Art

[0002] Liquid ejection apparatuses are known that eject a liquid such as solder paste containing particles from a nozzle using a reciprocating plunger. For example, a configuration is disclosed in which droplets are continuously ejected by repeatedly performing: moving the plunger forward in a non-contact state between the side surface of the liquid chamber through which the plunger is inserted and the side surface of the plunger to eject droplets from the nozzle, and then moving the plunger backward (see, for example, Patent Document 1).

[0003] However, in the conventional art, ejection defects may occur due to part of the pressure applied into the liquid chamber by the forward movement of the plunger toward the nozzle side being dispersed into the liquid supply path or the gap between the side surface of the plunger and the inner wall side surface of the liquid chamber, and nozzle clogging may occur due to aggregation of particles caused by retention of particles on the bottom surface on the nozzle side in the liquid chamber, crushing of particles near the bottom surface, or the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0005] The present invention has been made in view of the above, and an object thereof is to provide a liquid ejection head capable of improving ejection characteristics.

Means for Solving the Problem

[0006] The liquid dispensing device of the embodiment comprises a housing, a nozzle plate, and a plunger. The housing has a liquid chamber for storing a liquid containing particles, and a supply passage for supplying the liquid into the liquid chamber via a supply port provided in the liquid chamber. The nozzle plate has a nozzle for dispensing the liquid from the liquid chamber. The plunger is provided to be reciprocally movable within the liquid chamber and is long in the direction of reciprocating movement. The end face of the plunger on the nozzle side in the direction of reciprocating movement of the plunger is provided to be reciprocally movable within the liquid chamber along the direction of reciprocating movement between a first position in the direction of reciprocating movement within the liquid chamber and a second position in the direction of reciprocating movement within the liquid chamber, with the first position and the supply port on the nozzle side. The first gap in the intersecting direction between the side surface of the plunger and the inner wall surface of the liquid chamber, intersecting the direction of reciprocating movement, is greater than the particle diameter of the particles and less than or equal to twice the particle diameter. The nozzle plate has a tapered portion with the nozzle as the apex and widening in the direction away from the nozzle along the direction of reciprocating movement. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram of an example of a liquid dispensing device according to an embodiment. [Figure 2A] Figure 2A is an explanatory diagram of the movement of the plunger in the reciprocating direction. [Figure 2B] Figure 2B is an explanatory diagram of the movement of the plunger in the reciprocating direction. [Figure 3] Figure 3 is an enlarged schematic diagram of a part of the liquid dispensing device. [Figure 4] Figure 4 is a schematic diagram of an example of a modified liquid dispensing device. [Figure 5] Figure 5 is a schematic diagram of an example of a modified liquid dispensing device. [Figure 6] Figure 6 is a schematic diagram of an example of a modified liquid dispensing device. [Figure 7] Figure 7 is a schematic diagram of an example of a modified liquid dispensing device. [Figure 8] Figure 8 is a schematic diagram of an example of a modified liquid dispensing device. [Modes for carrying out the invention]

[0008] The embodiments of the liquid dispensing device of this embodiment will be described in detail below with reference to the attached drawings. The embodiments described below are all specific examples of the present disclosure. Therefore, the components, their arrangement positions, and connection configurations shown in the following embodiments are examples and are not intended to limit the present disclosure. Furthermore, components in the following embodiments that are not described in an independent claim will be described as optional components.

[0009] Furthermore, each figure is a schematic diagram and not necessarily a precise representation. In each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified. Moreover, the drawings and the following description are provided for the full understanding of the disclosure by those skilled in the art and are not intended to limit the subject matter described in the claims.

[0010] (First Embodiment) Figure 1 is a schematic diagram of an example of the liquid dispensing device 1 of this embodiment. Figure 1 shows a plan view of the liquid dispensing device 1. In this embodiment, the longitudinal direction of the plunger 4 of the liquid dispensing device 1, which will be described later, is referred to as the Z direction, and the width direction of the plunger 4, which is perpendicular to the Z direction, is referred to as the X direction and the Y direction. The X direction and the Y direction are perpendicular to each other.

[0011] The liquid dispensing device 1 comprises a housing 2, a nozzle plate 3, a plunger 4, and a cover 5.

[0012] The housing 2 has a liquid chamber 20 and a supply passage 21.

[0013] The liquid chamber 20 is a storage chamber for storing liquid 50. The housing 2 is provided with a long hole in the Z direction through which the plunger 4 is inserted, and this hole functions as the liquid chamber 20. In addition, the space on the nozzle 31 side of the liquid chamber 20 functions as a space for storing liquid 50.

[0014] Further, the liquid chamber 20 has a function of maintaining the pressure required to compress the stored liquid 50 to increase the pressure and discharge liquid droplets from the nozzle 31, as the plunger 4, which will be described later in detail, reciprocates. For this reason, the materials of the housing 2 constituting the liquid chamber 20 and the nozzle plate 3 to be described later are preferably materials that hardly cause pressure attenuation. For example, examples of the material of the housing 2 include metal materials, ceramic materials, and the like. Examples of the metal material include stainless steel, nickel, aluminum, and the like. Examples of the ceramic material include alumina, zirconia, silicon dioxide, and the like.

[0015] The liquid 50 is a discharge target by the liquid discharge device 1. The liquid 50 is a liquid material in which particles are contained in a liquid component.

[0016] The particles are, for example, metal particles, resin particles, and the like. The particle diameter of the particles is not limited. The particle diameter of the particles is, for example, 150 μm or less, 75 μm or less, 38 μm or less, 20 μm or less, 11 μm or less, etc., but is not limited thereto. Examples of the liquid 50 containing particles of 150 μm or less, 75 μm or less, 38 μm or less, 20 μm or less, and 11 μm or less include solder pastes of respective types from type 1 to type 8. In the present embodiment, an example in which the particle diameter of the particles contained in the liquid 50 is 2 μm to 15 μm will be described.

[0017] As the particles, those containing 90% or more of all spherical particles having a ratio of the major axis to the minor axis of the particle of 1.2 or less are used, and the major axis of the particles is defined as the particle diameter. The particle diameter is measured, for example, by the following method. (1) The particles are observed and measured with a microscope. (2) Measurement is performed by a sieve-type particle size distribution measurement test using a sieve of a predetermined particle range. (3) The particle size distribution of fine particles contained in the liquid material is measured by a laser diffraction particle size distribution measuring apparatus, and the average value thereof is defined as the particle diameter. There are various methods for measuring the particle diameter, but (3) is adopted in the present embodiment.

[0018] The liquid component contained in the liquid 50 may be any liquid material that can disperse particles.

[0019] The liquid 50 is, for example, a solder paste, a silver paste, a high-viscosity material, or the like. The high viscosity means, for example, that the viscosity is 10000 mPa·s to 500000 mPa·s. Further, the high viscosity may mean that the viscosity is 20000 mPa·s or more, or 30000 mPa·s to 500000 mPa·s or more. In the present embodiment, an embodiment in which the viscosity of the liquid 50 is 10 Pa·s or more will be described as an example.

[0020] The supply passage 21 communicates with the inside of the liquid chamber 20 via a supply port 21A provided on the inner wall side surface 2B of the liquid chamber 20, and is a supply passage that supplies the liquid 50 into the liquid chamber 20 via the supply port 21A.

[0021] The inner wall side surface 2B of the liquid chamber 20 is a surface along the Z direction, which is the reciprocating movement direction of the plunger 4, on the inner wall of the liquid chamber 20 that is a hole portion provided in the housing 2.

[0022] A pipe for supplying the liquid 50 stored in a supply tank is connected to the supply passage 21. The supply tank stores the liquid 50 in a sealed space. An air pipe is connected to the supply tank, and by applying air pressure to the supply tank, the liquid 50 stored in the supply tank is supplied to the supply passage 21 via the pipe. The liquid 50 supplied to the supply passage 21 passes through the gap between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the housing 2 via the supply port 21A, and is supplied into the liquid chamber 20. By adjusting the air pressure applied to the supply tank, the supply amount of the liquid 50 supplied into the liquid chamber 20 via the supply passage 21 is adjusted. In the present embodiment, an embodiment in which one supply passage 21 is provided in the housing 2 is shown as an example. However, a plurality of supply passages 21 may be provided in the housing 2.

[0023] The side surface 4B of the plunger 4 is a surface along the Z direction of the rod-shaped plunger 4 that is long in the Z direction.

[0024] The nozzle plate 3 is positioned to cover the liquid chamber 20 from below (in the -Z direction). The nozzle plate 3 is provided with a nozzle 31. In other words, the nozzle plate 3 constitutes the bottom surface of the space in the liquid chamber 20 that stores the liquid 50. The nozzle 31 is also positioned on the bottom surface of the space in the liquid chamber 20 that stores the liquid 50.

[0025] The nozzle 31 is the discharge port for discharging the liquid 50 from the liquid chamber 20. The nozzle diameter, which is the opening diameter of the nozzle 31, should be appropriately designed according to the desired discharge volume of liquid. However, it is preferable to set the minimum nozzle diameter to be about 7 to 10 times the diameter of the particles contained in the liquid 50. By adjusting the nozzle diameter within this range, nozzle clogging due to particles contained in the liquid 50 can be suppressed.

[0026] The material of the nozzle plate 3 is preferably one that does not cause pressure attenuation within the nozzle 31, and that allows the pressure applied to the liquid chamber 20 to reach the tip of the nozzle 31 without attenuation. For example, the material of the nozzle plate 3 may be a metal material, a ceramic material, etc. Specific examples of metal materials and ceramic materials are the same as described above.

[0027] The plunger 4 is a member that is long in the direction of reciprocating movement and is provided to move back and forth within the liquid chamber 20. The direction of reciprocating movement coincides with the Z direction. Also, the longitudinal direction of the plunger 4 coincides with the Z direction, which is the direction of reciprocating movement. The plunger 4 is provided to move back and forth in the Z direction within the liquid chamber 20 by being inserted into the liquid chamber 20, which is a cylindrical hole provided in the housing 2 that is long in the Z direction.

[0028] Furthermore, the plunger 4 is supported so that it can reciprocate in the Z direction with a gap between it and the side surface 4B of the liquid chamber 20, without the plunger 4 being in contact with the inner wall side surface 2B of the liquid chamber 20.

[0029] The central position of the plunger 4 in the orthogonal direction (XY direction) perpendicular to the reciprocating direction (Z direction) is positioned to coincide with the opening center of the nozzle 31 in the same orthogonal direction (XY direction). As will be described in detail later, the liquid 50 in the liquid chamber 20 is discharged from the nozzle 31 by the reciprocating movement of the plunger 4 along the reciprocating direction (Z direction) (details will be described later).

[0030] The plunger 4 only needs to be a long rod in the direction of reciprocating movement (Z direction), and its shape is not limited. The shape of the plunger 4 can be, for example, cylindrical, rectangular prism, or polygonal prism such as a hexagonal prism. In this embodiment, a cylindrical shape of the plunger 4 will be described as an example.

[0031] The material of the plunger 4 is preferably one that does not easily cause a decrease in the pressure applied in the liquid chamber 20. Examples of materials for the plunger 4 include metal materials and ceramic materials. Specific examples of metal materials and ceramic materials are the same as described above.

[0032] The plunger 4 is moved back and forth in the reciprocating direction (Z direction) by a drive mechanism (not shown in the figure).

[0033] The drive mechanism for plunger 4 can be an actuator that utilizes a motor, a piezoelectric element, an elastic body such as a spring, a solenoid valve, or air pressure.

[0034] The drive mechanism can employ appropriate means depending on the application. When a configuration is used to discharge various liquids 50 ranging from low to high viscosity, it is preferable to use a drive mechanism that allows the stroke of the plunger 4 to be adjusted within a certain range. Furthermore, when a piezoelectric element is used as the actuator, it is preferable to use a laminate of multiple piezoelectric elements stacked together as the drive mechanism so that a large driving force and high-speed operation are possible. When using a piezoelectric element, since the displacement of the piezoelectric element is very small, it is preferable to adjust the plunger 4 so that its stroke can be expanded by reciprocating the plunger 4 via a lever mechanism or the like.

[0035] The stroke of the plunger 4 when performing micro-discharge is, for example, 5 μm to 1000 μm, but when discharging a high-viscosity liquid 50, it is preferable to lengthen the stroke, for example, by adjusting it to 50 μm to 1000 μm. Micro-discharge refers to the discharge of droplets of liquid 50 discharged from the nozzle 31 with a diameter of several tens to several hundred μm when the discharged liquid adheres to the target object, or droplets with a volume of 1 nl or less (preferably 0.1 nl to 0.5 nl or less).

[0036] Figures 2A and 2B are explanatory diagrams illustrating the reciprocating movement of the plunger 4.

[0037] The plunger 4 is provided to be able to reciprocate between a first position S1 (see Figure 2A) and a second position (see Figure 2B).

[0038] The first position S1 is the position of the end face 4A on the nozzle 31 side of the plunger 4 in the reciprocating direction (Z direction) of the plunger 4. The first position S1 may be any of the following in the reciprocating direction (Z direction): on the side opposite to the nozzle 31 (+Z direction) of the supply port 21A, on the side opposite to the nozzle 31 (-Z direction) of the supply port 21A, or on the side opposite to the nozzle 31 (-Z direction) of the supply port 21A. In other words, when the end face 4A of the plunger 4 is located at the first position S1, the side surface 4B of the plunger 4 may not cover the supply port 21A at all in the Z direction (the reciprocating direction of the plunger 4), cover a part of it, or cover it completely. In the following, the state in which the end face 4A of the plunger 4 on the nozzle 31 side is positioned at the first position S1 may be described as the plunger 4 being in the first position S1.

[0039] The second position S2 is the position of the end face 4A on the nozzle 31 side of the plunger 4 in the reciprocating direction (Z direction). The second position S2 is a position within the liquid chamber 20 in the reciprocating direction (Z direction) that is closer to the nozzle 31 than the first position S1 and the supply port 21A. More specifically, the second position S2 is closer to the nozzle 31 than the first position S1 in the reciprocating direction (Z direction), and is also closer to the nozzle 31 side (-Z direction) of the end of the supply port 21A on the nozzle 31 side (-Z direction side). That is, when the end face 4A of the plunger 4 is in the second position S2, the side surface 4B of the plunger 4 completely covers the supply port 21A in the reciprocating direction (Z direction). Hereafter, the state in which the end face 4A of the plunger 4 on the nozzle 31 side is located in the second position S2 may be described as the plunger 4 being in the second position S2.

[0040] The reciprocating movement of the plunger 4 between the first position S1 and the second position S2 along the reciprocating direction (Z direction) causes the liquid 50 in the liquid chamber 20 to be discharged from the nozzle 31 as droplets 50A.

[0041] Returning to Figure 1, we continue the explanation.

[0042] Cover 5 is a component that covers the opening of the liquid chamber 20 on the side opposite the nozzle 31 (+Z direction side) in the housing 2.

[0043] The sealing member 6 is an annular member provided on the inner circumferential surface of the opening of the liquid chamber 20 in the housing 2 on the side opposite the nozzle 31 (+Z direction side). The sealing member 6 provides a liquid-tight seal between the cover 5 and the housing 2 and the side surface 4B of the plunger 4. In other words, the sealing member 6 maintains the airtight seal of the liquid chamber 20 by the cover 5.

[0044] The sealing member 6 may be any member capable of liquid-tightly sealing the space between the cover 5 and housing 2 and the side surface 4B of the plunger 4. For example, a rubber O-ring or the like can be used as the sealing member 6. Furthermore, from the viewpoint of ensuring airtightness even when sliding occurs due to the reciprocating movement of the plunger 4, a known sealing material such as an X-ring may be used as the sealing member 6.

[0045] The sealing member 7 is an annular member that liquid-tightly seals the end face 2A of the housing 2 on the nozzle 31 side and the end face 3B of the nozzle plate 3 on the housing 2 side. The sealing member 7 prevents the liquid components of the liquid 50 stored in the liquid chamber 20 from seeping out through the gap between the housing 2 and the nozzle plate 3. Therefore, it is possible to suppress particle aggregation caused by liquid component seepage and discharge failure due to clogging of the nozzle 31.

[0046] The sealing member 7 may be any member capable of liquid-tightly sealing the end face 2A of the housing 2 on the nozzle 31 side and the end face 3B of the nozzle plate 3 on the housing 2 side. For example, the sealing member 7 may be a rubber O-ring, X-ring, or other sealing material.

[0047] Figure 3 is an enlarged schematic diagram of a part of the liquid dispensing device 1.

[0048] The nozzle plate 3 has a tapered portion TP that widens in diameter away from the nozzle 31 along the reciprocating movement direction (Z direction) of the plunger 4, with the nozzle 31 as its apex. In other words, the nozzle plate 3 is provided with a tapered portion TP, which is a conical hole that widens away from the nozzle 31 with the nozzle 31 as its apex.

[0049] In other words, in the liquid dispensing device 1 of this embodiment, the section enclosed by the end face 4A of the plunger 4 on the nozzle 31 side and the tapered portion TP of the nozzle plate 3 functions as a storage section for storing the liquid 50 in the liquid chamber 20.

[0050] Preferably, the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31, matches the diameter of the cylindrical hole in the housing 2 through which the plunger 4 is inserted, or is larger than the diameter of the cylindrical hole. Figures 1 to 3 show an example of a configuration in which the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31, matches the diameter of the cylindrical hole in the housing 2 through which the plunger 4 is inserted.

[0051] The apex angle θ of the tapered portion TP should be an angle that can suppress aggregation due to the accumulation of particles contained in the liquid 50 in the liquid chamber 20. Preferably, the apex angle θ of the tapered portion TP is 20 degrees or more and 90 degrees or less.

[0052] Preferably, the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31, matches the diameter of the cylindrical hole in the housing 2 through which the plunger 4 is inserted. That is, it is preferable that the boundary between the inner wall side surface 2B of the liquid chamber 20 of the housing 2 and the tapered portion TP of the nozzle plate 3 is formed continuously. This continuous state means that the outer diameter of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31 matches the diameter of the cylindrical hole in the housing 2 through which the plunger 4 is inserted.

[0053] Because the nozzle plate 3 is provided with a tapered portion TP, particles contained in the liquid 50 stored in the liquid chamber 20 are prevented from accumulating and agglomerating within the liquid chamber 20.

[0054] Furthermore, by setting the apex angle θ of the tapered portion TP to 90 degrees or less, it is possible to suppress the accumulation of liquid 50 due to a decrease in fluidity between the end face 4A of the plunger 4 and the nozzle 31 side surface (bottom surface) of the liquid chamber 20 when the plunger 4 is positioned at the second position S2. Also, by setting the apex angle θ of the tapered portion TP to 90 degrees or less, when the plunger 4 moves from the first position S1 to the second position S2, the liquid 50 flows along the inclined surface of the tapered portion TP toward the nozzle 31, thereby suppressing the occurrence of accumulation due to a decrease in fluidity and suppressing nozzle clogging of the nozzle 31 due to the aggregation of particles contained in the liquid 50.

[0055] Furthermore, as shown in Figure 1, it is preferable that the end face 3B of the nozzle plate 3, which has a tapered portion TP, on the side opposite the nozzle 31 (+Z direction side), is in contact with the end face 2A of the housing 2 on the nozzle 31 side (-Z direction side). Also, as described above, it is preferable to provide a sealing member 7 to liquid-tightly seal the end face 3B of the nozzle plate 3 on the side opposite the nozzle 31 (+Z direction side) and the end face 2A of the housing 2 on the nozzle 31 side (-Z direction side).

[0056] By arranging end faces 3B and 2A in contact and sealing them liquid-tight, it is possible to suppress the liquid components of the liquid 50 stored in the liquid chamber 20 from seeping out through the gap between the housing 2 and the nozzle plate 3. This suppresses the tendency for particles in the liquid chamber 20 to aggregate within the liquid chamber 20.

[0057] The first gap G1 in the intersecting direction (Y direction) that intersects the reciprocating movement direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20 is larger than the particle diameter of the particles contained in the liquid 50 and is no more than twice the particle diameter. More preferably, the first gap G1 is 1.2 times or more and 2 times or less the particle diameter of the particles contained in the liquid 50, and even more preferably, it is 1.5 times or more and 2 times or less the particle diameter of the particles contained in the liquid 50.

[0058] When the plunger 4 moves from the first position S1 to the second position S2, the pressure loss in the first gap G1 is greater than the pressure loss in the first gap G1 compared to the pressure loss in the region of the liquid chamber 20 where the liquid 50 is stored. This is because the first gap G1 intersects the reciprocating movement direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20. In other words, the pressure applied to the liquid chamber 20 when the plunger 4 moves from the first position S1 to the second position S2 is suppressed from diffusing away from the nozzle 31 (+Z direction) through the first gap G1, thus suppressing the pressure loss in the liquid chamber 20. As a result, the liquid 50 in the liquid chamber 20 is suitably discharged to the outside from the nozzle 31.

[0059] Furthermore, by ensuring that the first gap G1 in the intersecting direction (Y direction) that intersects the reciprocating movement direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20 satisfies the above range, it is possible to suppress the crushing of particles contained in the liquid 50 present in the first gap G1 during the reciprocating movement of the plunger 4.

[0060] Returning to Figure 3, the explanation continues. When the end face 4A on the nozzle 31 side of the plunger 4 in the reciprocating direction (Z direction) is located at the second position S2, the second gap G2, which is the minimum distance in the reciprocating direction (Z direction) between the end face 4A of the plunger 4 and the inner wall surface of the liquid chamber 20, is preferably 20 times or more the particle diameter of the particles contained in the liquid 50. The maximum value of the second gap G2 should be the maximum value that can achieve a pressure capable of discharging droplets 50A from the nozzle 31 by the pressure applied to the liquid chamber 20 by the plunger 4 as it moves from the first position S1 to the second position S2.

[0061] Next, the operation of the liquid dispensing device 1 of this embodiment will be described.

[0062] This will be explained using Figures 2A and 2B.

[0063] In step A, the drive mechanism moves the plunger 4 away from the nozzle 31 in the reciprocating direction (Z direction) (+Z direction) until the end face 4A of the plunger 4 is in the first position S1 (Figure 2A).

[0064] Then, liquid 50 is supplied from the supply passage 21 to the supply port 21A and into the liquid chamber 20, filling the liquid chamber 20 with liquid 50. More specifically, air pressure is applied to the supply tank in which the liquid 50 is stored, and the liquid 50 is supplied from the supply tank to the supply passage 21, thereby filling the liquid chamber 20 with liquid 50 through the supply port 21A and the first gap G1 between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the housing 2. As described above, for example, the viscosity of the liquid 50 is 10 Pa·s or more, and the particle size of the particles contained in the liquid 50 is, for example, about 2 μm to 15 μm.

[0065] Next, in step B, the drive mechanism moves the plunger 4 in the direction approaching the nozzle 31 (-Z direction) in the reciprocating direction (Z direction) until the end face 4A of the plunger 4 is in the second position S2 (Figure 2B).

[0066] As the plunger 4 moves toward the nozzle 31, the internal pressure of the liquid chamber 20 increases, and the liquid 50 inside the liquid chamber 20 is pushed out from the nozzle 31. Subsequently, as the plunger moves toward the nozzle, the pushed-out portion is torn and broken apart, and discharged as a droplet 50A. The second position S2 is a position where, at most, the end face 4A of the plunger 4 is in contact with a part of the bottom surface of the liquid chamber 20 on the nozzle 31 side.

[0067] The stroke amount and movement speed of the plunger 4 from the first position S1 to the second position S2 should be adjusted according to the amount of liquid droplets 50A to be discharged from the nozzle 31. For example, when discharging a small amount of liquid droplets 50A of a few nl or less from the nozzle 31, it is preferable to set the movement time required for the plunger 4 to move from the first position S1 to the second position S2 to be shorter. However, the higher the viscosity of the liquid 50, the more likely it is that the liquid droplets 50A will not be separated from the liquid 50 in the liquid chamber 20 and will not be discharged as liquid droplets 50A. In such cases, the stroke amount of the plunger 4 from the second position S2 to the first position S1 and from the first position S1 to the second position S2 should be increased.

[0068] Then, in the liquid dispensing device 1, the series of steps A and B are repeatedly executed, causing droplets 50A to be sequentially dispensed from the nozzle 31.

[0069] As described above, the liquid dispensing device 1 of this embodiment comprises a housing 2, a nozzle plate 3, and a plunger 4. The housing 2 has a liquid chamber 20 for storing liquid 50 containing particles, and a supply passage 21 for supplying liquid 50 into the liquid chamber 20 via a supply port 21A provided in the liquid chamber 20. The nozzle plate 3 has a nozzle 31 for dispensing the liquid 50 from the liquid chamber 20. The plunger 4 is a member that is long in the direction of reciprocating movement (Z direction) and is provided to be able to move back and forth within the liquid chamber 20.

[0070] The plunger 4 has an end face 4A on the nozzle 31 side in the reciprocating direction (Z direction) of the plunger 4 that is provided to reciprocate within the liquid chamber 20 along the reciprocating direction (Z direction) between a first position S1 in the reciprocating direction (Z direction) within the liquid chamber 20 and a second position S2 that is on the nozzle 31 side of the first position S1 and the supply port 21A in the reciprocating direction (Z direction) within the liquid chamber 20. The first gap G1 in the intersecting direction that intersects the reciprocating direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20 is larger than the particle diameter and less than or equal to twice the particle diameter. The nozzle plate 3 has a tapered portion TP that widens in diameter toward the direction away from the nozzle 31 along the reciprocating direction, with the nozzle 31 as the apex.

[0071] As described above, in the plunger 4 of the liquid discharge device 1 of this embodiment, the end face 4A of the plunger 4 is provided to be reciprocally movable in the reciprocating direction (Z direction) between a first position S1 (see Figure 2A) and a second position (see Figure 2B). The first position S1 is the position of the end face 4A on the nozzle 31 side of the plunger 4 in the reciprocating direction (Z direction) of the plunger 4. The second position S2 is a position in the liquid chamber 20 in the reciprocating direction (Z direction) that is closer to the nozzle 31 than the first position S1 and the supply port 21A.

[0072] Therefore, in the plunger 4 of the liquid discharge device 1 of this embodiment, when the end face 4A of the plunger 4 is in the second position S2, which is pushed out as far as the nozzle 31 side, the side surface 4B of the plunger 4 completely covers the supply port 21A in the reciprocating direction (Z direction).

[0073] Therefore, in the liquid discharge device 1 of this embodiment, it is possible to suppress the dispersion of the pressure applied to the liquid chamber 20 by the plunger 4 to the supply passage 21 side via the supply port 21A.

[0074] Furthermore, the nozzle plate 3 of the liquid discharge device 1 in this embodiment is provided with a conical tapered portion TP that has the nozzle 31 as its apex and widens in diameter toward the direction away from the nozzle 31 along the reciprocating movement direction (Z direction) of the plunger 4. In other words, the nozzle plate 3 is provided with a tapered portion TP, which is a conical hole that widens toward the direction away from the nozzle 31 with the nozzle 31 as its apex. Therefore, when pressure is applied to the liquid chamber 20 as the plunger 4 moves from the first position S1 to the second position S2, the particles contained in the liquid 50 are guided toward the nozzle 31 along the inclined surface of the tapered portion TP and flow without stagnation. Thus, the fluidity of the liquid 50 in the liquid chamber 20 is ensured, and the stagnation and aggregation of particles contained in the liquid 50 within the liquid chamber 20 is suppressed. In addition, because the tapered portion TP is provided, aggregation and crushing of particles contained in the liquid 50 at the bottom surface on the nozzle 31 side of the liquid chamber 20 are suppressed. In other words, when the plunger 4 moves from the first position S1 to the second position S2, pressure is applied to the liquid chamber 20, causing the liquid 50 in the liquid chamber 20 to flow rapidly in a short time, and the pressure inside the liquid chamber 20 to rise. This suppresses the crushing and aggregation of particles contained in the liquid 50. As a result, clogging of the nozzle 31 is suppressed, and in the liquid discharge device 1 of this embodiment, it becomes possible to discharge minute liquid droplets 50A over a long period of time.

[0075] Furthermore, in the liquid discharge device 1 of this embodiment, the first gap G1 in the intersecting direction (Y direction) that intersects the reciprocating movement direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20 is larger than the particle diameter of the particles contained in the liquid 50 and is no more than twice the particle diameter.

[0076] When the first gap G1 satisfies the above range, when the plunger 4 moves from the first position S1 to the second position S2, the pressure loss in the first gap G1 of the pressure applied to the liquid chamber 20 by this movement becomes larger than the pressure loss in the region of the liquid chamber 20 where the liquid 50 is stored (the region on the nozzle 31 side). In other words, the diffusion of the pressure applied to the liquid chamber 20 by the movement of the plunger 4 from the first position S1 to the second position S2 through the first gap G1 away from the nozzle 31 (+Z direction) is suppressed, and the pressure loss in the liquid chamber 20 is suppressed. As a result, the pressure drop due to pressure dispersion in the liquid chamber 20 is suppressed, and the liquid 50 in the liquid chamber 20 is suitably discharged to the outside from the nozzle 31.

[0077] Furthermore, by ensuring that the first gap G1 in the intersecting direction (Y direction) that intersects the reciprocating movement direction (Z direction) between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20 satisfies the above range, it is possible to suppress the crushing of particles contained in the liquid 50 present in the first gap G1 during the reciprocating movement of the plunger 4.

[0078] Therefore, in the liquid discharge device 1 of this embodiment, a portion of the pressure applied to the liquid chamber 20 by the movement of the plunger 4 toward the nozzle 31 is dispersed into the liquid supply passage 21 and the first gap G1 between the side surface 4B of the plunger 4 and the inner wall side surface 2B of the liquid chamber 20, which can cause discharge failures, and nozzle clogging due to aggregation or crushing caused by the accumulation of particles near the nozzle 31 can be suppressed.

[0079] Therefore, the liquid dispensing device 1 of this embodiment can improve the dispensing characteristics.

[0080] Furthermore, in the liquid dispensing device 1 of this embodiment, clogging of the nozzle 31 is suppressed, making it possible to stably dispense minute liquid droplets 50A over a long period of time.

[0081] Furthermore, as described above, the liquid dispensing device 1 of this embodiment is provided with a sealing member 7. The sealing member 7 is an annular member that liquid-tightly seals the nozzle 31 side end face 2A of the housing 2 and the housing 2 side end face 3B of the nozzle plate 3. The sealing member 7 prevents the liquid components of the liquid 50 stored in the liquid chamber 20 from seeping out through the gap between the housing 2 and the nozzle plate 3.

[0082] As the plunger 4 repeatedly moves back and forth in the direction of reciprocating movement (Z direction), the liquid chamber 20 is subjected to high pressure for a long period of time, and liquid components contained in the liquid 50 may seep out from the liquid chamber 20 to the outside through the gap between the housing 2 and the nozzle plate 3. When liquid components seep out from the liquid chamber 20 to the outside, the proportion of particles in the liquid chamber 20 increases, and clogging of the nozzle 31 may occur due to particle aggregation. On the other hand, by further providing a sealing member 7, the seepage of liquid components contained in the liquid 50 to the outside through the gap between the housing 2 and the nozzle plate 3 can be suppressed, and clogging of the nozzle 31 due to particle aggregation in the liquid chamber 20 can be further suppressed.

[0083] (Variation 1) As described in the above embodiment, the tapered portion TP provided on the nozzle plate 3 should be conical in shape, with the nozzle 31 as its apex and expanding in diameter in the direction away from the nozzle 31 along the reciprocating movement direction (Z direction) of the plunger 4.

[0084] Therefore, in the above embodiment, a configuration was described as one in which the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31 (+Z direction), matches the diameter of the hole in the housing 2 through which the plunger 4 is inserted. However, these outer diameters and diameters may not match.

[0085] Figure 4 is a schematic diagram of an example of the liquid dispensing device 1B of this modified example.

[0086] Liquid dispensing device 1B has the same configuration as liquid dispensing device 1 of the above embodiment, except that the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31 (+Z direction) is less than the diameter of the hole in the housing 2 through which the plunger 4 is inserted.

[0087] If the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31 (+Z direction) is less than the diameter of the hole in the housing 2 through which the plunger 4 is inserted, the volume of the liquid chamber 20 becomes smaller compared to the liquid dispensing device 1 of the above embodiment. As a result, a higher pressure is applied to the liquid chamber 20 when the plunger 4 moves to the second position S2, making it possible to discharge a smaller amount of liquid droplets 50A from the nozzle 31 compared to the liquid dispensing device 1 of the above embodiment.

[0088] On the other hand, in the configuration of this modified example, opposing regions F are generated between the end face 4A of the plunger 4 and the planar end face 3A of the nozzle plate 3 that is aligned with the ZY plane and faces the plunger 4. In this case, aggregation and crushing of particles contained in the liquid 50 present in the opposing region F within the liquid chamber 20 may occur. For this reason, as described in the above embodiment, it is preferable that the outer diameter of the end of the tapered portion TP, which is a conical hole, on the side opposite the nozzle 31 (+Z direction), and the diameter of the hole in the housing 2 through which the plunger 4 is inserted are the same, as shown in Figures 1 to 3.

[0089] (Modification 2) In the above embodiment, the diameter of the cylindrical plunger 4 was described as being the same from one end to the other along the extension direction (Z direction) of the plunger 4. However, the plunger 4 may also have a configuration in which one end on the nozzle 31 side in the reciprocating direction (Z direction) has a first small-diameter portion that is smaller in diameter than the central portion in the reciprocating direction (Z direction) of the plunger 4.

[0090] Figure 5 is a schematic diagram of an example of the liquid dispensing device 1C of this modified example.

[0091] The liquid dispensing device 1C has the same configuration as the liquid dispensing device 1 of the above embodiment, except that the shape of one end of the plunger 4 on the nozzle 31 side in the reciprocating movement direction (Z direction) is different.

[0092] In this modified example, the plunger 4 has a first small-diameter portion 41 at one end on the nozzle 31 side in the reciprocating direction (Z direction), which has a smaller diameter than the central portion 40 in the reciprocating direction (Z direction) of the plunger 4. The third gap G3, which is the gap in the direction of intersection (Y direction) between the side surface 4B of the first small-diameter portion 41 and the side surface 2B of the inner wall of the liquid chamber 20, is larger than the first gap G1 in the direction of intersection (Y direction) between the side surface 4B of the central portion 40 and the side surface 2B of the inner wall of the liquid chamber 20.

[0093] The length of the first small-diameter portion 41 in the reciprocating movement direction (Z direction) is not limited. The length of the first small-diameter portion 41 in the Z direction is such that at least a portion of the side surface of the first small-diameter portion 41 faces the supply port 21A when the end face 4A of the plunger 4 is located in the first position S1.

[0094] As described in the above embodiment, if the first gap G1 is made larger than the particle diameter of the particles contained in the liquid 50 and no more than twice the particle diameter, it may become difficult to supply the liquid 50 from the supply passage 21 to the liquid chamber 20. This is because the flow resistance in the path through which the liquid 50 flows from the supply passage 21 to the liquid chamber 20 via the first gap G1 becomes high, and even if the liquid 50 is supplied to the supply passage 21 from the outside at high pressure, it may become difficult for the liquid 50 to flow into the liquid chamber 20.

[0095] On the other hand, in this modified example, a first small-diameter portion 41 is provided at one end of the plunger 4 on the nozzle 31 side in the reciprocating direction (Z direction) of the plunger 4, which has a smaller diameter than the central portion 40 in the reciprocating direction (Z direction) of the plunger 4. As a result, the liquid 50 flows from the supply passage 21 into the liquid chamber 20 through a third gap G3 that is wider than the first gap G1, thereby suppressing the difficulty of the liquid 50 flowing into the liquid chamber 20.

[0096] Furthermore, the third gap G3, which is the gap in the intersecting direction (Y direction) between the side surface 4B of the first small diameter portion 41 and the inner wall side surface 2B of the liquid chamber 20, is preferably adjusted to be 20 times or less the particle size of the particles contained in the liquid 50, from the viewpoint of suppressing pressure dispersion within the liquid chamber 20.

[0097] (Variation 3) In the above embodiment, the diameter of the cylindrical plunger 4 was described as being the same from one end to the other along the extension direction (Z direction) of the plunger 4. However, the plunger 4 may also have a configuration in which a second small-diameter portion protrudes tapered toward the nozzle 31 at one end on the nozzle 31 side in the reciprocating direction (Z direction).

[0098] Figure 6 is a schematic diagram of an example of the liquid dispensing device 1D of this modified example.

[0099] The liquid dispensing device 1D has the same configuration as the liquid dispensing device 1 of the above embodiment, except that the shape of one end of the plunger 4 on the nozzle 31 side in the reciprocating movement direction (Z direction) is different.

[0100] In this modified example, the plunger 4 may have a second small-diameter portion 42 that tapers toward the nozzle 31 at one end on the nozzle 31 side in the reciprocating direction (Z direction). For example, the inclined surface of the second small-diameter portion 42 may be at the same angle as the inclined surface of the tapered portion TP of the nozzle plate 3, or it may be at a different angle.

[0101] When the plunger 4 is configured to have a second small-diameter portion 42, the fourth gap G4 between the inclined surface 4C of the second small-diameter portion 42 and the inclined surface of the tapered portion TP of the nozzle plate 3 becomes smaller than when the plunger 4 is configured not to have a second small-diameter portion 42.

[0102] Therefore, in this modified configuration, the volume of the liquid chamber 20 is smaller compared to the liquid dispensing device 1 of the above embodiment. As a result, a higher pressure is applied to the liquid chamber 20 by the movement of the plunger 4 from the first position S1 to the second position S2, making it possible to discharge a smaller amount of liquid droplets 50A from the nozzle 31 compared to the liquid dispensing device 1 of the above embodiment.

[0103] Furthermore, because the fourth gap G4 is very narrow, the pressure loss in the liquid chamber 20 when the plunger 4 is moved from the first position S1 to the second position S2 is reduced, allowing high pressure to be efficiently applied to the liquid chamber 20, making it possible to discharge an extremely small amount of liquid droplet 50A from the nozzle 31.

[0104] On the other hand, in the configuration of this modified example, the fourth gap G4 between the inclined surface 4C of the second small diameter portion 42 of the plunger 4 and the inclined surface of the tapered portion TP of the nozzle plate 3 is narrow, so there is concern that the fluidity of the liquid 50 in the region facing the inclined surface 4C and the tapered portion TP may deteriorate. For this reason, it is preferable to adjust the shape of the second small diameter portion 42 and the second position S2 of the plunger 4 so that the fourth gap G4 between the inclined surface 4C of the second small diameter portion 42 of the plunger 4 and the inclined surface of the tapered portion TP of the nozzle plate 3 is larger than the gap that can suppress the accumulation of liquid 50 located in the fourth gap G4 and suppress the crushing and aggregation of particles in the fourth gap G4. At a minimum, the fourth gap G4 needs to be set to 20 times or more the particle diameter.

[0105] (Modification 4) Furthermore, the liquid dispensing device 1D may be configured such that the plunger 4 has a second small-diameter portion 42 as shown in Figure 6, and the nozzle plate 3 may be a two-dimensional planar (XY plane) substrate that does not have a tapered portion TP and is aligned in a direction perpendicular to the reciprocating movement direction (Z direction) of the plunger 4 (see liquid dispensing device 1E in Figure 7).

[0106] Figure 7 is a schematic diagram of an example of the liquid dispensing device 1E of this modified example.

[0107] In this case, the space within the liquid chamber 20 that is continuous with both ends (inclined surfaces 4C) of the plunger 4 in the orthogonal direction is wider than the space that is continuous with the end face 4A. As a result, the pressure applied to the liquid 50 in the space continuous with both ends (inclined surfaces 4C) of the plunger 4 in the orthogonal direction is reduced, and the fluidity of the liquid 50 is ensured, thereby suppressing the crushing of particles contained in the liquid 50.

[0108] (Variation 5) In the above embodiment, the diameter of the plunger 4 is the same from one end to the other along the extension direction (Z direction) of the plunger 4, and a cylindrical shape was described as an example. However, the plunger 4 may also have a configuration in which a protrusion is provided at one end on the nozzle 31 side in the reciprocating movement direction (Z direction).

[0109] Figure 8 is a schematic diagram of an example of the liquid dispensing device 1F of this modified example.

[0110] The liquid dispensing device 1F has the same configuration as the liquid dispensing device 1 of the above embodiment, except that the shape of one end of the plunger 4 on the nozzle 31 side in the reciprocating movement direction (Z direction) is different.

[0111] In this modified example, the plunger 4 has a protrusion 43 at one end on the nozzle 31 side in the reciprocating direction (Z direction), which has a smaller diameter than the central part 40 of the plunger 4 in the reciprocating direction (Z direction), and whose central position C in the intersecting direction that crosses the reciprocating direction (Z direction) coincides with the center of the opening of the nozzle 31.

[0112] When the plunger 4 is configured to have a protrusion 43, the volume inside the liquid chamber 20 is smaller compared to when the plunger 4 is configured not to have a protrusion 43. As a result, a higher pressure is applied inside the liquid chamber 20 when the plunger 4 moves from the first position S1 to the second position S2, making it possible to discharge a smaller amount of liquid droplets 50A from the nozzle 31 compared to the liquid discharge device 1 of the above embodiment.

[0113] The shape of the protrusion 43 is not limited. As shown in Figure 8, the cross-sectional shape of the cross section along the reciprocating movement direction (Z direction) of the plunger 4 may be rectangular, or it may be semicircular.

[0114] Furthermore, it is preferable to adjust the distance between the end face 4A of the protrusion 43 and the tapered portion TP of the nozzle plate 3 in the reciprocating direction (Z direction) to a distance that can suppress the crushing and aggregation of particles in the liquid 50 when the plunger 4 is in the second position S2.

[0115] While embodiments and modifications of this disclosure have been described above, these embodiments and modifications are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments and modifications can be implemented in a variety of other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0116] The details of the present invention will be described below with reference to examples, but the present invention is not limited in any way to these examples. [Examples]

[0117] Using the liquid dispensing device 1C shown in Figure 7, droplets 50A were dispensed, and the occurrence of clogging of the nozzle 31 was confirmed.

[0118] For liquid 50, a solder paste containing particles with an average particle size of 12 μm (viscosity 100 Pa·s) was used.

[0119] Discharge tests were conducted by adjusting the operating conditions of the plunger 4 in the reciprocating direction (Z direction) and the supply conditions of the liquid 50 so that the discharge volume of droplet 50A was 2.5nl to 3nl. When droplet 50A was continuously discharged at a rate of 80 shots per second and the nozzle 31 was observed, no clogging of the nozzle 31 was observed up to 1,884,000 shots, confirming that stable discharge was possible.

[0120] Furthermore, this technology can also be configured as follows. (1) A housing having a liquid chamber for storing a liquid containing particles, and a supply path for supplying the liquid into the liquid chamber via a supply port provided in the liquid chamber, A nozzle plate having a nozzle for discharging the liquid in the liquid chamber, A plunger, which is long in the direction of reciprocating movement, is provided to be able to move back and forth within the liquid chamber, Equipped with, The plunger is The end face of the plunger on the nozzle side in the reciprocating direction is provided so as to be able to reciprocate within the liquid chamber along the reciprocating direction between a first position in the reciprocating direction within the liquid chamber and a second position on the nozzle side of the supply port in the reciprocating direction within the liquid chamber. The first gap in the intersecting direction between the side surface of the plunger and the side surface of the inner wall of the liquid chamber, which intersects the reciprocating movement direction, is larger than the particle diameter of the particle and less than or equal to twice the particle diameter. The aforementioned nozzle plate is The nozzle is the apex, and the tapered portion is widened in diameter in the direction away from the nozzle along the reciprocating movement direction, Liquid discharge device. (2) When the nozzle-side end face of the plunger in the reciprocating direction is positioned at the second position, the second gap, which is the minimum distance in the reciprocating direction between the end face of the plunger and the inner wall surface of the liquid chamber, is 20 times or more the particle diameter. (1) The liquid dispensing device described above. (3) The plunger is The plunger has a first small-diameter portion at one end on the nozzle side in the reciprocating direction, which has a smaller diameter than the central portion in the reciprocating direction. The third gap in the intersecting direction between the side surface of the first small diameter portion and the side surface of the inner wall of the liquid chamber is larger than the first gap. A liquid dispensing device as described in (1) or (2). (4) The plunger is The nozzle side has a second small-diameter portion that tapers and protrudes toward the nozzle side at one end in the reciprocating movement direction, When the nozzle-side end face of the plunger in the reciprocating direction is positioned at the second position, the fourth gap in the intersecting direction between the outer wall surface of the second small-diameter portion of the plunger and the inner wall surface of the liquid chamber is larger than the first gap. A liquid dispensing device as described in any one of (1) to (3). (5) The plunger is One end of the nozzle side in the reciprocating direction has a protrusion that is smaller in diameter than the central part of the plunger in the reciprocating direction, and whose central position in the intersecting direction coincides with the nozzle. A liquid dispensing device as described in any one of (1) to (4). (6) The aforementioned nozzle plate is The end face of the nozzle plate on the side opposite the nozzle is in contact with the end face of the housing on the nozzle side. A liquid dispensing device as described in any one of (1) to (5). (7) The apex angle of the tapered portion is 90 degrees or less. A liquid dispensing device as described in any one of (1) to (6). (8) The boundary between the inner wall surface of the liquid chamber of the housing and the tapered portion of the nozzle plate is formed continuously. A liquid dispensing device as described in any one of (1) to (7). (9) The end face of the housing on the nozzle side and the end face of the nozzle plate on the housing side are sealed with a sealing material. A liquid dispensing device as described in any one of (1) to (8). [Industrial applicability]

[0121] The liquid dispensing devices 1, 1B to 1F of this embodiment and its modifications can dispense minute amounts of liquid 50 containing particles such as solder paste, silver paste, and filler-containing adhesives, and can therefore be used for surface mounting and wiring of fine chip components, bonding of fine components, and other applications.

[0122] Furthermore, the liquid dispensing devices 1, 1B to 1F of this embodiment and its modified versions can not only dispense minute amounts of liquid 50, but also easily increase the amount of liquid 50 dispensed by adjusting the descent time of the plunger 4, so they can be used not only for small-area applications but also for coating large areas. In addition, because the liquid dispensing devices 1, 1B to 1F of this embodiment and its modified versions are small in size, they can dispense a predetermined amount of liquid 50 not only to flat surfaces but also to uneven substrates and three-dimensional shapes. [Explanation of Symbols]

[0123] 1, 1B, 1C, 1D, 1E, 1F Liquid discharge device 2 cabinets 3 Nozzle Plate 4 plungers 7. Sealing member 21 Supply route 21A supply port 31 nozzles TP tapered section

Claims

1. A housing having a liquid chamber for storing a liquid containing particles, and a supply path for supplying the liquid into the liquid chamber via a supply port provided in the liquid chamber, A nozzle plate having a nozzle for discharging the liquid in the liquid chamber, A plunger, which is long in the direction of reciprocating movement, is provided to be able to move back and forth within the liquid chamber, Equipped with, The plunger is The end face of the plunger on the nozzle side in the reciprocating direction is provided so as to be able to reciprocate within the liquid chamber along the reciprocating direction between a first position in the reciprocating direction within the liquid chamber and a second position on the nozzle side of the supply port in the reciprocating direction within the liquid chamber. The first gap in the intersecting direction between the side surface of the plunger and the side surface of the inner wall of the liquid chamber, which intersects the reciprocating movement direction, is larger than the particle diameter of the particle and less than or equal to twice the particle diameter. The aforementioned nozzle plate is The nozzle is the apex, and the tapered portion is widened in diameter in the direction away from the nozzle along the reciprocating movement direction, Liquid discharge device.

2. When the end face of the plunger on the nozzle side in the reciprocating direction is located at the second position, the second gap, which is the minimum distance in the reciprocating direction between the end face of the plunger and the inner wall surface of the liquid chamber, is 20 times or more the particle diameter. The liquid dispensing device according to claim 1.

3. The plunger is The plunger has a first small-diameter portion at one end on the nozzle side in the reciprocating direction, which has a smaller diameter than the central portion in the reciprocating direction. The third gap in the intersecting direction between the side surface of the first small diameter portion and the side surface of the inner wall of the liquid chamber is larger than the first gap. The liquid dispensing device according to claim 1.

4. The plunger is The nozzle side has a second small-diameter portion that tapers and protrudes toward the nozzle side at one end in the reciprocating movement direction, When the nozzle-side end face of the plunger in the reciprocating direction is positioned at the second position, the fourth gap in the intersecting direction between the outer wall surface of the second small-diameter portion of the plunger and the inner wall surface of the liquid chamber is larger than the first gap. The liquid dispensing device according to claim 1.

5. The plunger is One end of the nozzle side in the reciprocating direction has a protrusion that is smaller in diameter than the central part of the plunger in the reciprocating direction, and whose central position in the intersecting direction coincides with the nozzle. The liquid dispensing device according to claim 1.

6. The aforementioned nozzle plate is The end face of the nozzle plate on the side opposite the nozzle is in contact with the end face of the housing on the nozzle side. The liquid dispensing device according to claim 1.

7. The apex angle of the tapered portion is 90 degrees or less. The liquid dispensing device according to claim 1.

8. The boundary between the inner wall surface of the liquid chamber of the housing and the tapered portion of the nozzle plate is formed continuously. The liquid dispensing device according to claim 1.

9. The end face of the housing on the nozzle side and the end face of the nozzle plate on the housing side are sealed with a sealing material. The liquid dispensing device according to claim 1.

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