Liquid ejecting device

Abstract

To provide a liquid matter discharge device that is directly coupled to a valve and in which a pre-packed hotmelt adhesive can be used.SOLUTION: A discharge device discharges a liquid matter in a syringe by driving a needle in the syringe and an actuator of a valve body to drive the needle. In the discharge device, a heating source of the valve body 20 is a heating block 22 including: a nozzle reception part 30 that receives and supports a valve seat assembly 3 at a tip end of the syringe 1; a surrounding wall part 26 having an opening 33 in a front part thereof and surrounding a depth side of a jacket 2, the opening enabling attaching and detaching of the jacket; and a block body including a heater. A heat conductive lid 48 is accommodated between a pair of linkage parts 28 and thermally connected with the linkage parts, thereby forming a semi-cylindrical inner circumferential surface 27 having a closed circle shape and being in contact with the jacket. The syringe is heated via the jacket by heat transferred to the surrounding wall part 26 and the lid.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a liquid discharge device (also called a valve) for accurately discharging a small amount of an adhesive onto a circuit board, for example, when mounting electronic components or the like on the circuit board. More specifically, the present invention relates to a liquid discharge device applicable to the accurate discharge of a small amount of a hot melt adhesive pre-packed in a syringe.

Background Art

[0002] In recent years, hot melt adhesives have been widely used in the fields of electronic devices and the like. In particular, polyurethane (PUR)-based hot melt adhesives are widely used, starting from the manufacturing process of display panels for smartphones.

[0003] PUR (Poly Urethane Reactive) - based hot melt adhesives are of a type that reacts with moisture in the air and cures. Once they harden, they do not soften even when heated and are adhesives with high durability. However, for the equipment (referred to as a discharge device or an applicator (pump)) for applying them, the sealing members are easily damaged, and once they harden, reheating for softening is not possible, so maintenance is not easy.

[0004] For this reason, syringe-type hot melt adhesives packed with an aluminum laminate sheet or the like to enhance airtightness and circulated in a sealed state, that is, hot melt adhesives pre-packed in syringes, are being circulated. In particular, when accurately discharging a small amount of hot melt adhesive, it is more desirable to use a hot melt adhesive pre-packed in a form directly connected to a valve.

[0005] On the one hand, as a liquid discharge device for accurately discharging a small amount of adhesive, a liquid filled in a small container called a so-called syringe is filled in the syringe and the inside of the syringe is constantly pressurized, so that a needle (valve stem) that forms a valve between the valve seat at the discharge port of the syringe is attracted by a solenoid for a very short time, and a liquid discharge device that discharges only during that time has been proposed (Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, although the syringe for hot melt is formed of a heat-resistant resin, when it is pressurized from the inside for discharge in a state heated to 120°C to 200°C, many syringes made of polypropylene, even though they have heat resistance, tend to soften, the syringe bulges, and in some cases, there is a risk of rupture.

[0008] For this reason, a method is generally used in which the syringe itself is housed in a pressure vessel, heated after making the pressure difference between the inside and outside of the syringe zero, and the hot melt is pressure-fed to an adjacent valve head.

[0009] Some improvement is required to use a hot-melt adhesive prepacked in a form directly connected to a valve. For example, it is conceivable to adopt a structure in which a syringe filled with a hot-melt adhesive is housed and sealed in the atmosphere of a pressure vessel that combines heating and pressurization of the hot-melt adhesive, and heated while pressurizing to eliminate the pressure difference inside and outside the syringe. However, there is a problem that the ejection device becomes large. For this reason, the valve head is heavy and has the drawback of becoming large. When mounted on a robot such as an automatic machine for coating work, there arises a problem that the weight load on the robot increases.

[0010] Also, in the case of a hot-melt adhesive, it is necessary to efficiently warm the entire syringe. However, according to the ejection device for a liquid material described in Patent Document 1, when trying to warm the entire syringe, heat is transferred to the entire valve, deteriorating workability, damaging parts that are vulnerable to heat as a device, and particularly when a solenoid is used as an actuator, there is a problem of loss of accuracy. Therefore, it is difficult to adopt a structure for warming the whole.

[0011] An object of the present invention is to provide an ejection device for a liquid material that can also use a hot-melt adhesive prepacked in a form directly connected to a valve.

Means for Solving the Problems

[0012] In order to achieve such an object, the invention according to claim 1 has a syringe that constitutes a needle valve with a needle inserted therein with a valve seat assembly attached to the tip opening, an actuator that drives the needle, and a heat source that heats the liquid material filled in the syringe, and a syringe housing that houses the syringe ContainerIt is composed of a valve body with a space, and while storing a syringe in a syringe storage space, an actuator and a needle are magnetically connected, so that when the needle valve at the tip of the syringe is opened by driving the actuator, the liquid in the heated syringe is discharged by the pressure applied in the syringe. In the liquid discharge device provided as such, the syringe is housed in a heat-conductive jacket and attached to the valve body. The heating source of the valve body is a heating block composed of a nozzle receiving portion that supports the valve seat assembly at the tip of the syringe, a surrounding wall portion that has an opening at the front that enables the insertion and removal of the jacket and surrounds the depth side of the jacket, and a block body with a heater. The surrounding wall portion has a semi-cylindrical inner peripheral surface that is in close contact with the outer peripheral surface of the jacket, and a connecting portion composed of a pair of parallel flat surfaces extending in the tangential direction from both ends of the semi-cylindrical inner peripheral surface. A heat-conductive lid that is housed between the pair of connecting portions and is thermally connected to the connecting portions constitutes a closed circular inner peripheral surface that is in close contact with the jacket between the semi-cylindrical inner peripheral surfaces, and the syringe is heated through the jacket by the heat transmitted to the surrounding wall portion and the lid.

[0013] Further, in the liquid discharge device according to claim 1, the lid functions as a heat source and a heat dissipation surface by having both side surfaces in close contact with the connecting portions of the surrounding wall portion and contacting the nozzle receiving portion at the bottom surface, so that the heat of the heating block is transmitted and it is heated.

[0014] Here, the lid preferably includes a heat-insulating handle and a combination of a ball plunger and a hole into which the ball of the ball plunger fits on at least one side surface facing the flat surfaces on both sides of the surrounding wall portion of the heating block, and is detachably provided on the heating block. - The ball of the ball plunger fits into the hole, and it is preferably detachably provided on the heating block.

[0015] Also, the syringe is on the tip side with a sphereIt is a cylindrical body comprising a discharge part for attaching a face funnel part and a valve seat assembly, and the jacket is composed of a cylindrical part covering the cylindrical part of the syringe and a frustoconical cylindrical body surrounding the spherical funnel part, and it is preferable that the jacket and the syringe are in a clearance-fitting state where they can be inserted and removed from each other and the syringe is heated through the jacket.

[0016] Moreover, it is preferable that the heater is a heater module inserted into a groove or a hole provided in the block body of the heating block.

[0017] Here, in the heater module, a temperature sensor is covered and attached to the surface of the heater case in contact with the heating block by a thin-film heat-resistant tape, a recess is provided on the surface of the heater case under the temperature sensor, and an elastic member is housed, and it is preferable that the temperature sensor is constantly biased so as to press against the heating block.

Advantages of the Invention

[0018] According to the liquid discharge device described in claim 1, it is also possible to use a hot melt adhesive prepacked in a form directly connected to the valve. That is, even when pressurizing from the inside for discharge in a state heated to 150°C to 200°C, the outside of the syringe is almost completely covered and suppressed by the jacket, so there is no risk of the syringe swelling or bursting.

[0019] Moreover, compared with the case of adopting a structure in which the syringe itself is housed in a pressure vessel so that no pressure difference occurs between the inside and outside of the syringe and heating is performed while applying a discharge pressure, since it is only necessary to house it in a sheath-like jacket slightly larger than the syringe, the valve head can be made extremely compact. In addition, since a hot melt adhesive prepacked in a form directly connected to the valve can also be used, no seal is required, the structure is simplified, and maintenance becomes very easy. For this reason, miniaturization of the discharge device can be realized, and even when mounted on a robot such as an automatic machine for performing a coating operation, the weight load on the robot can be reduced.

[0020] Furthermore, the heat of the heater is transmitted to the entire area of the hot melt adhesive filled in the syringe through the nozzle receiving part of the heating block and the jacket surrounded by the surrounding wall part and the lid. Therefore, the hot melt adhesive filled in the syringe can be heated uniformly throughout without uneven distribution and maintained at a desired temperature.

Brief Description of the Drawings

[0021]

Figure 1

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Mode for Carrying Out the Invention

[0022] Hereinafter, the configuration of the present invention will be described in detail based on the embodiments shown in the drawings. In this specification, unless otherwise specified, the vertical direction is the longitudinal direction of the valve body (the direction in which the needle for opening and closing the valve moves: the axial direction), the upper side refers to the junction box side of the valve body, and the lower side refers to the heating block side. Also, the front-rear direction is the direction orthogonal to the longitudinal direction of the valve body, the rear refers to the back side of the valve body, and the front refers to the front side where the syringe is inserted and removed. Further, the left-right direction refers to the width direction orthogonal to the longitudinal direction and the front-rear direction of the valve body, and regardless of the actual orientation of the valve body, when moving in the longitudinal direction, it is called ascending or rising or descending. Also, the liquid ejection device according to the present invention generally called a valve generally ejects the liquid downward, but depending on the shape of the object to be coated, the mounting angle of the valve body may be changed to eject obliquely downward. However, in this specification, the case of ejecting downward will be mainly described.

[0023] As shown in FIG. 2, the liquid discharge device (also commonly referred to as a valve) according to this embodiment is composed of a syringe set 6 including a syringe 1 filled with a liquid material, such as a hot melt adhesive (not shown), and a valve body 20 incorporating a drive source (actuator) for removably assembling the syringe set 6 and discharging the liquid, and a heating source.

[0024] As shown in FIG. 1, the syringe set 6 is composed of a syringe 1 filled with a liquid material, such as a hot melt adhesive, a valve seat assembly 3 attached to the tip opening of the syringe 1, a needle (valve body) 4 inserted into the syringe 1 and forming a needle valve between the valve seat assembly 3, a syringe adapter 5 fitted into a rear end opening 11 of the syringe 1 to slidably hold the rear end side of the needle 4, and a sheath-shaped heating and protective jacket (hereinafter simply referred to as jacket 2) that contains the syringe 1 while exposing the valve seat assembly 3 and the syringe adapter 5.

[0025] The syringe 1 is inserted into the jacket 2 and then inserted into the syringe housing of the valve body 20. Container It is stored in space 69. Here, syringe 1 is preferably formed of a resin, such as polypropylene, that can sufficiently withstand heat at the melting temperature of the hot melt adhesive, for example, about 180°C to 200°C. In this embodiment, syringe 1 is formed, for example, as a cylinder, but is provided with a funnel portion (referred to as a spherical funnel portion 8) that is narrowed into a spherical shape so that the cross-sectional area gradually decreases at the tip side, and discharge portion 10 provided with a female screw portion into which the luer of valve seat assembly 3 is screwed.

[0026] On the one hand, the jacket 2 is a cylindrical body made of a material with excellent heat conductivity, such as an aluminum alloy. It is composed of a cylindrical part (jacket body) 2a that covers the cylindrical part of the syringe 1 and a frustum-shaped cylindrical body (jacket tip) 2b that surrounds the spherical funnel part 8 of the syringe. It is preferable for heat transfer that the inner diameter of the cylindrical part 2a of the jacket 2 and the outer diameter of the syringe 1 are set in a clearance fit state where they can be inserted and removed while being almost in close contact. This enables good heat transfer to the syringe 1 and prevents deformation of the syringe 1 even when it is heated under an applied internal pressure. In particular, the spherical funnel part 8, which is easily deformed by the application of internal pressure, can be surrounded and supported by the frustum-shaped cylindrical body 2b, thereby preventing expansion of the spherical funnel part 8 and rupture caused thereby.

[0027] The jacket 2 is provided with a knob 7 for preventing burns. For example, the knob 7 is provided near the opening 19 for inserting the syringe 1 into the jacket 2. The replacement operation of the syringe 1 is structured such that the syringe 1 can be removed from the valve body 20 together with the jacket 2 by grasping the knob 7 of the jacket 2, and then the syringe 1 can be removed from the jacket 2 outside the valve body 20 (see Fig. 3).

[0028] According to this syringe assembly 6, even when heated to 120°C at which the hot melt begins to melt with an internal pressure for ejection applied to the syringe 1, the jacket 2 surrounding the syringe 1 suppresses its deformation. Moreover, since the parts in contact with the hot melt adhesive in the syringe 1 are concentrated at two points, the needle 4 and the luer, maintenance is very easy. That is, in the ejection device of this embodiment, it is a direct type in which a valve mechanism is directly attached to the syringe filled with the hot melt that has been heated and melted into a liquid state. Therefore, there is no need for a mechanism to seal the pressurized and melted hot melt, and since the hot melt does not adhere to the valve body 20, the maintenance load can be significantly reduced.

[0029] The needle 4 is composed of, for example, an impact stick 18 made of tungsten carbide at the tip portion that contacts the valve seat 74, an impact rod 17 made of stainless steel that supports it, and a connect sleeve 16 that is crowned on the head of the impact rod 17, that is, the head of the needle 4, as shown in FIG. 14. In the case of this embodiment, in order to magnetically couple with the connecting member 63 of the valve body 20, a connect sleeve 16 made of a ferromagnetic material is crowned on the head of the impact rod 17, but it is not particularly limited to this. When the entire needle 4 or the impact rod 17 is made of a ferromagnetic material, the connect sleeve 16 is not particularly required. Of course, when a magnet is equipped on the top of the needle 4, the material of the needle 4 is not affected.

[0030] On the other hand, the valve seat assembly 3 is composed of, for example, a seat holder 72 having a threaded portion on the outer peripheral surface, a nozzle retainer 73, and a valve seat 74, and is of a luer lock (screw-in) type that is fixed by screwing the threaded portion of the seat holder 72 into the female threaded portion provided at the discharge portion 10 at the tip of the syringe 1. This valve seat assembly 3 is provided so that it can be positioned in place by contacting the conical inner surface of the nozzle catcher 25 disposed on the heating block 22 side coaxially with the positioning member 64 of the junction box 21.

[0031] In this embodiment, the connection between the syringe 1 loaded into the syringe accommodation space 69 and the junction box 21 of the valve body 20 can be attached in one touch by fitting the syringe adapter 5 fitted to the rear end opening 11 of the syringe 1 into the connection port 70 of the positioning member 64.

[0032] The syringe adapter 5 is integrally formed in one block having, for example, a first plug portion 12 that fits with the syringe 1, a flange portion 15 that abuts against the opening edge 9 of the syringe 1, and a second plug portion 13 that fits with the connection port 70 of the positioning member 64. Further, the needle 4 is passed through a hole 14 penetrating the center of each of the plug portions 12 and 13, and the discharge air pressure can be applied inside the syringe. An O-ring is attached to each of the plug portions 12 and 13 to provide a sealable structure.

[0033] The coaxiality of the needle 4 and the syringe 1 is maintained by the valve seat assembly 3 at the lower end of the syringe 1 and the syringe adapter 5 at the upper end. On the other hand, since the solenoid 61 on the valve body 20 side is fastened by a magnet (not shown) housed in the yoke 65, even when a misalignment occurs between the connecting member 63 on the valve body 20 side and the needle 4, it is possible to maintain the coaxiality of the needle 4 and the valve seat 74.

[0034] On the other hand, the valve body 20 incorporates an actuator 61 that detachably holds the syringe assembly 6 and is magnetically coupled to the needle 4 housed in the syringe 1 to move the needle 4 forward and backward toward the valve seat assembly 3. By simply setting the syringe assembly 6 on the valve body 20, the actuator 61 of the valve body 20 and the needle 4 mounted in the syringe 1 are magnetically coupled and integrated, and the discharge of the hot melt adhesive in the syringe 1 is controlled by the actuator 61. In addition, since the head drive mechanism incorporating a mechanism for driving the needle 4 in the present embodiment and a mechanism for applying a discharge pressure to the liquid material filled in the syringe 1 is described in detail in Japanese Patent No. 5629866, detailed description is omitted and only an outline is described.

[0035] Here, the needle 4 may be directly driven by an actuator built into the valve body 20, or may be indirectly driven via a member (driven member) driven by the actuator. In the present embodiment, for example, a solenoid 61 is adopted as the actuator, and an armature 62 and a connecting member 63 are built into the valve body 20 as members (i.e., driven members) attracted by the solenoid 61, and an example provided to transmit the movement of the armature 62 attracted by exciting the solenoid to the needle 4 via the connecting member 63 will be mainly described.

[0036] As shown in FIG. 13, for example, the valve body 20 includes a junction box 21 that houses a solenoid 61 for opening and closing a needle valve and draws in and connects a power cable and an air hose, a heating block 22 that receives and holds the syringe set 6 and heats it, and a cross-sectionally U-shaped platform 23 that connects these and partitions a syringe accommodation space 69 inside. Further, the junction box 21 is provided with a solenoid 61, an armature 62 magnetically attracted to the solenoid 61, a connecting member 63, and a positioning member 64 that moves up and down by the application of air pressure and fits with the syringe adapter 5. By being connected to the needle 4 built into the syringe 1 by magnetic coupling, the needle 4 can be operated while inserted into the syringe 1, and it is provided so as to be detachable from the valve body 20. In this embodiment, the connecting member 63 and the needle 4 have a separate structure, and a magnet is used to firmly fasten the two for the required connection between them. Therefore, when the syringe 1 is set in the platform 23, the alignment of the connecting member 63 and the needle 4, which move up and down integrally in conjunction with the armature 62 or with a temporary delay, is automatically performed by magnetic coupling, so that the structure does not require delicate readjustment that occurs during syringe replacement. Incidentally, the magnet that magnetically couples the needle 4 and the connecting member 63 can be provided on at least one of the connecting member 63 or the needle 4, or preferably both. In this embodiment, it is housed in a cylindrical yoke 65 and assembled to the connecting member 63. Incidentally, the solenoid 61 shown in the figure is fixed inside the junction box 21 while being housed in a housing, and the symbol 61 indicates the housing itself, but it is expressed as a solenoid for convenience of explanation.

[0037] In the case of this embodiment, the connecting member 63 has an integral structure in which the armature 62 and the magnet yoke 65 are connected to each other via a magnetic shielding member, for example, a non-ferrous metal or an engineering plastic material, and is housed in the housing so as to penetrate the solenoid 61, and is structured to be forcibly pushed down by the biasing force of a biasing means such as a compression coil spring (not shown) that pushes the needle 4 back to a fixed position. In this embodiment, the armature 62 and the connecting member 63 are integrated, but it is not limited thereto, and they may have a separable separate structure and an axial gap is set therebetween, so that although the force of the biasing means for pushing the needle 4 back to the fixed position is applied to the connecting member 63 and thus to the needle 4 side, the armature 62 side may be structured not to receive the force of the biasing means.

[0038] The junction box 21 is provided with an air cooling circuit that maintains a constant exciting magnetic force by circulating a cooling fluid, such as air, water, liquid nitrogen, etc., for cooling the solenoid 61. Further, a lock-up sleeve 67 is housed in the junction box 21, and Positioning member 64 is supported so as to be able to protrude and retract. An armature 62 is housed in the space between the solenoid 61 and the piston portion 66 of the positioning member 64 surrounded by this lock-up sleeve 67, and is provided so as to be movable in the axial direction by being adsorbed toward the solenoid 61 side by the excitation of the solenoid 61.

[0039] The junction box 21 is provided with a valve stroke adjustment mechanism 77 that incorporates a torque limiter and enables accurate setting of the stroke amount of the needle 4 by accurately determining the zero point, independently of the biasing mechanism that constantly applies a biasing force for pushing the needle 4 back to a fixed position, and is provided to enable stroke adjustment under the application of a certain spring load and not to receive a strong load at the initial stage of excitation during small discharge.

[0040] The positioning member 64 has a hole-shaped connection port 70 at the lower part that conforms to the end shape of the syringe 1 or the shape of the second plug portion 13 of the syringe adapter 5. For example, by fitting the plug portion 13 of the syringe adapter 5 and the connection port 70, centering and connecting the syringe 1 are made possible, and a sealing structure is formed between the junction box 21, the lock-up sleeve 67, and the plug portion 13 of the syringe adapter 5. And the positioning member 64 has a structure that it is lowered toward the syringe 1 by the pressure of an operating gas, such as an inert gas like compressed air or nitrogen gas (hereinafter simply referred to as compressed air), and is coaxially accommodated. At the same time, when the positioning member 64 is pushed up to the upper limit of its movable range, the connection port 70 at the lower end is disengaged from the plug portion 13 of the syringe adapter 5, and further the armature 62 and the connecting member 63 are pushed up, creating a gap between the yoke 65 and the syringe adapter 5. That is, the positioning member 64 of the present embodiment serves as a mechanism for attaching and detaching the syringe 1 to and from the valve body 20 by moving forward and backward toward the syringe 1, a biasing mechanism for continuously pushing the syringe 1 toward the heating block 22, and a sealing mechanism for establishing a flow path for supplying the air supplied through the valve body 20 into the syringe 1.

[0041] The hot melt adhesive solidifies immediately when cooled. Therefore, by heating the entire valve seat assembly 3 and jacket 2 via the heating block 22, not only the hot melt adhesive just before discharge is heated, but it is also necessary to keep the entire amount of the hot melt adhesive in the syringe 1 in a molten state. Thus, heating of the syringe 1 is provided such that heat is transferred not only, for example, via the valve seat assembly 3 at the tip, but also from the heat of the heating block 22 through the jacket 2 to the peripheral wall of the syringe 1. Specifically, as shown in FIG. 14, the heat of the heater module 35 passes through the nozzle catcher 25 of the nozzle receiving portion 30 of the heating block 22 from the valve seat assembly 3 at the tip of the syringe 1, and heat is transmitted from the jacket 2 through the surrounding wall portion 26 and the lid 48 to substantially the entire area of the syringe 1 so that the hot melt adhesive is heated and kept warm as a whole.

[0042] In the case of this embodiment, the heating block 22 is preferably formed of a material excellent in heat conductivity, such as die casting of an aluminum alloy, etc., transfers the heat of the heater module 35 to the syringe 1, heats and melts the hot melt adhesive sealed in the syringe 1, and keeps it warm to prevent solidification. Incidentally, the hot melt adhesive becomes liquid when the resin melts by heating, for example, to 120 to 200°C.

[0043] The heating block 22 is for supporting the tip side of the syringe, that is, the valve seat assembly 3, and heating the adhesive in the syringe, such as hot melt, and is formed of a material excellent in heat conductivity, such as an aluminum alloy. The heating block 22 of this embodiment is composed of, for example, as shown in FIGS. 11 and 12, a nozzle receiving portion 30 that supports the nozzle at the tip of the syringe 1, a substantially U-shaped surrounding wall portion 26 that surrounds most of the cylindrical portion 2a of the jacket 2, and a block body 31 that includes a heater module 35, and is integrally formed by, for example, aluminum die casting. A stepped hole 32 is formed in the nozzle receiving portion 30 at a position coaxial with the central axis of the syringe, and the nozzle catcher 25 is fitted therein.

[0044] The front side of the heating block 22 needs to be opened for the attachment and detachment of the syringe set 6. Therefore, the surrounding wall portion 26 that surrounds the syringe of the heating block 22 is composed of a semi-circular (180°) cylindrical portion (referred to as a semi-cylindrical portion 27) that is in close contact with the outer peripheral surface of the jacket 2, and a connecting portion 28 composed of a pair of left and right flat surfaces that extend in the tangential direction from both ends of the semi-cylindrical portion 27 and are parallel to each other, and is formed in a U-groove shape so as to form an opening 33 on the front side of the heating block 22. For this reason, it is difficult to heat the entire circumferential surface of the jacket 2 from all directions with the heating block 22. However, if the heating regions are unevenly distributed, it may cause partial curing or overheating of the hot melt. Therefore, while providing the front opening 33 of the heating block 22 that enables the loading and unloading of the syringe set 6, it is desirable to adopt a structure that can heat the jacket 2 from all directions by surrounding it. Therefore, in the present embodiment, a lid 48 that closes the opening 33 on the front side of the heating block 22, that is, the space between the pair of connecting portions 28, is provided so as to form a closed circular space between the semi-cylindrical portion 27 of the surrounding wall portion 26 and the inner peripheral surface of the lid 48.

[0045] The lid 48 is a lid member that closes the space, i.e., the opening 33, between a pair of connecting portions 28 of the surrounding wall portion 26 of the heating block 22 and is in close contact with the front surface of the jacket 2 exposed on the opening 33 side. It is formed of a material with excellent thermal conductivity, such as aluminum or copper. The surface 51 of the lid 48 facing the jacket 2 has an inner peripheral surface that is recessed in a semi-circular shape with substantially the same radius of curvature as the jacket 2, as shown in FIG. 2, FIG. 9, or FIG. 10, and forms a closed circle that surrounds the entire circumferential surface of the jacket 2 between the semi-circular surrounding wall portion 26 of the heating block 22. On the other hand, the lid 48 functions as a heat source and a heat dissipation surface by being in close contact with the connecting portions 28 of the surrounding wall portion 26 of the heating block 22 on both side surfaces 52 and by contacting the nozzle receiving portion 30 of the heating block 22 at the bottom surface 53, through which the heat of the heating block 22 is transmitted and it is heated. For this reason, the jacket 2 is heated from all directions in a state of being in close contact or almost in close contact with the semi-cylindrical portion 27 of the surrounding wall portion 26 of the heating block 22 and the lid 48, and it becomes possible to hold the molten hot melt adhesive inside the syringe 1 to be accommodated at a desired temperature. Also, the heat of the cartridge heater 46 is transmitted to the hot melt adhesive filled in the syringe 1 through the nozzle catcher 25 of the nozzle receiving portion 30 and the valve seat assembly 3. Therefore, the hot melt adhesive filled in the syringe 1 can be heated uniformly throughout without being unevenly distributed and held at a desired temperature.

[0046] As shown in FIG. 2, for example, the lid 48 is provided with ball plungers 49 on both side surfaces 52 that are in contact with the connecting portions 28 of the heating block 22, and is detachably provided by a simple operation of fitting the ball plungers 49 into holes 29 provided at corresponding positions of the connecting portions 28. Here, if the ball plungers 49 of the lid 48 are provided only on one side surface, since it is biased toward the opposite side surface, it is expected that the contact between the heating block 22 and the lid 48 will be more reliable and the heat transfer method will be even better.

[0047] The lid 48 is attached with a heat-insulating handle, for example, an L-shaped handle 50 that bends forward. By enabling the removal of the lid 48 by grasping the handle 50 without touching the lid 48, it is structured to prevent burns.

[0048] On the other hand, as shown in FIGS. 6 and 7, a heater module 35 is provided in the block body 31 on the back of the heating block 22. The heater module 35 houses a cartridge heater (a heater in which a nichrome wire as a heating element is covered with a metal pipe (sheath)) 46 in a heater case 41 formed of a material with excellent thermal conductivity, such as an aluminum alloy. The heater module 35 is inserted into the groove 34 on the back of the block body 31, and by simply inserting the junction bush 36 at the head into the recess (female part) 38 in the cover case 37 arranged on the block body 31, it is electrically connected to the electrical system on the side of the valve body 20 and is also mechanically connected to the cover case 37 by a light press fit. The junction bush 36 is, for example, a heat-resistant insulating bush made of PEEK resin, and holds a pair of pin terminals 39 for energizing the cartridge heater 46 and a pair of pin terminals 40 for signal detection of the temperature sensor 42 so as to project upward.

[0049] As shown in FIGS. 16(A) and (B), the heater module 35 is provided with a temperature sensor 42, and is provided to control the energization amount to the cartridge heater 46 to an appropriate temperature while measuring the temperature of the heating block 22, which is the object to be heated, so that the temperature can be adjusted to a predetermined temperature. Here, the temperature sensor 42 is provided on the surface of the heater case 41 in contact with the heating block 22, for example, the front surface, and measures the temperature of the heating block 22 by closely adhering to the surface of the groove 34 of the heating block 22, so that the deviation between the actual temperature of the heating block 22 and the set temperature is reduced.

[0050] In the case of this embodiment, for example, a platinum resistance temperature sensor is used as the temperature sensor 42. The temperature sensor 42 is covered by a thin-film heat-resistant tape 45 such as a polyamide film, and is fixed to the front surface of the case 41. For example, the sensor 42 is fixed by being attached to the front surface side of the case 41 with a 50-μm Kapton tape (registered trademark of DuPont, USA) 45. Here, in order to avoid an excessive load when the temperature sensor 42 is fixed by screwing while pressing the heater module 35 against the heating block 22, the temperature sensor 42 is arranged on the recess (dip) 43 provided on the front surface of the case 41 and then fixed with the thin-film heat-resistant tape 45. Thus, the temperature sensor 42 is elastically supported by an elastic member such as a spring 44 housed in the recess 43, and is provided so as to be elastically pressed against the back side of the object to be heated (heating block 22).

[0051] The heater module 35 is housed in a groove 34 formed on the back surface of the heating block 22 and fixed with screws 47. The groove 34 and the case 41 are preferably made to have a clearance fit in order to enable sliding or detachment after fitting the case 41 while making the heat conduction between the two good. Since the cartridge heater 46 needs to be able to heat to 150 to 200 °C in a relatively short time of several minutes, it has a problem of being more likely to fail than a heater used in a relatively low temperature range. Therefore, it is preferable to simplify the replacement by modularizing the cartridge heater 46. The removal of the modularized cartridge heater 46 is easy, and the reinstallation work can also be easily performed, which is convenient. That is, after loosening the screw 47 on the back surface of the heater module 35, the cartridge heater 46 is removed, the cartridge heater 46 is replaced, and then the case 41 is inserted into the groove 34 of the heating block 22, the junction bushing 36 is fitted, and then screwed, so that it can be easily installed, and the replacement work can be completed in a short time.

[0052] The cover case 37 is an intermediate component for supplying the power cable drawn from the junction box 21 through the air-relay box 59 and the cooling fluid to the heater module 35 or the bridge plate 24. As shown in FIG. 15, for example, the cover case 37 incorporates a conductor pin 71 for energizing the cartridge heater 46 and a conductor pin 72 for detecting the signal of the temperature sensor 42, and is arranged to be electrically connected to the heat-resistant insulating junction bush 36 fitted in the recess 38 at the bottom. Further, the base ends of the conductor pins 71 and 72 are fixed with POM (polyacetal resin) washers 73 and then housed in the cavities at the upper part of the cover case 37. The energizing conductor pin 71 and the signal-detecting conductor pin 72 are housed so as to project toward the recess 38 through four through holes (not shown) penetrating the cover case 37 in the vertical direction. At the same time, a spring 75 for pushing back the junction bush 36 is housed in the through holes.

[0053] The air-relay box 59 is interconnected to the junction box 21 and the cover case 37 by, for example, knockout pins (not shown) and a stainless pipe 74.

[0054] When a solenoid is used as the actuator, since the exciting force becomes weak as the temperature rises and as a result the discharge amount becomes unstable, it is preferable to adopt a structure in which the heat of the heating block 22 is difficult to be transmitted to the junction box 21 side. On the other hand, in this embodiment, the platform 23 is made of an aluminum alloy in order to be lightweight and highly rigid. Therefore, the heating block 22 and the platform 23 are connected to each other with a bridge plate, for example, a stainless steel bridge plate 24 made of a material having relatively poor thermal conductivity (low thermal conductivity) interposed therebetween, so that the heat of the heating block 22 is not transmitted to the platform 23 side.

[0055] For example, as shown in FIGS. 7 and 10, a pair of left and right bridge plates 24 are erected on the block body 31 of the heating block 22, and a platform 23 is connected to the bridge plate 24, so that the heating block 22 and the junction box 21 are integrated. At this time, in order to minimize the contact area between the bridge plate 24 and the heating block 22, the bottom surface 54 of the bridge plate 24 in contact with the heating block 22 is formed in a corrugated shape and is provided so as to contact the heating block 22 with a minimum area. Further, between the bridge plate 24 and the heating block 22, a stainless steel shim ring 55 through which a fastening screw 57 passes is interposed so that the bridge plate 24 and the heating block 22 are not in direct contact. The bridge plate 24 and the heating block 22 are connected so that the bridge plate 24 is erected with respect to the heating block 22 via the shim ring 55 by screwing the screw 57 through the communication hole 56 opening from the bottom surface of the heating block 22 into the female screw 58 on the bottom surface 54 of the bridge plate 24. Incidentally, the bridge plate 24 and the heating block 22 are also connected, for example, by fitting a knockout pin and a mating hole in the vicinity of the front and rear ends of the bridge plate 24 as necessary.

[0056] At the same time, the pair of bridge plates 24 are screwed to the plastic cover case 37 on the heating block 22 from the side, while being screwed to the side surface of the bridge plate 24 so as to be sandwiched between both side edges of the platform 23 having a U-shaped cross section. Thereby, the heating block 22 and the platform 23 are connected to each other via the stainless steel bridge plate 24 and the plastic cover case 37. Therefore, the heat generated in the heating block 22 is blocked to some extent from being transmitted to the platform 23 side.

[0057] Also, inside the bridge plate 24, although not shown in the figure, a cooling circuit is provided that circulates cooling fluid, such as cooling air, supplied from the actuator side and then returns it around the solenoid of the junction box 21. The structure is designed to cool the heat transmitted from the heating block 22. For example, the cooling fluid flowing inside the left bridge plate 24 flows through the communication passage 76 inside the cover case 37 to the cooling circuit of the opposite bridge plate 24, then is refluxed to the communication passage inside the cover case 37 again, and then is refluxed through the air relay block 59 to pass around the solenoid of the junction box 21. At this time, the solenoid is cooled. Then, it is discharged from the junction box 21 of the valve body 20 to the outside.

[0058] With the above-described heat insulation connection structure and cooling air circuit structure, the structure is such that the heat of the heater module 35 applied to the heating block 22 is prevented from being transmitted to the junction box 21 side.

[0059] In the discharge device of the present embodiment, the heater module 35 is arranged on the back side of the heating block 22, and both side surfaces, the front side of the heating block 22, and the lower part of the lid 48 are covered with a material having poor thermal conductivity, such as a protector 60 made of stainless steel, so that the operator is prevented from accidentally touching the heating block 22 and the lid 48 and getting burned (see FIG. 8). This protector 60 is formed into a spring structure, for example, by bending a stainless steel plate into a U shape, and sandwiches the heating block 22 with, for example, a heat insulating material interposed therebetween and is fixed only by frictional force. At the same time, the jacket 2 is structured to surround the lid 48 in a non-contact manner so as to form an air heat insulation layer therebetween. Therefore, it can be easily attached or removed. Accordingly, for the operator, since the heat source is arranged on the back side (the back side), the risk of being burned is eliminated, and the work becomes easier.

[0060] According to the hot melt adhesive discharging device configured as described above, after inserting the syringe 1 sealed with the hot melt adhesive into the jacket 2 and then mounting it in the syringe accommodation space 69 of the valve body 20, the heat from the heating block 22 heated by receiving the heat generation of the heater module 35 is transmitted to the hot melt adhesive sealed in the syringe 1 through the nozzle catcher 25 and the jacket 2. The hot melt adhesive is heated to a temperature suitable for discharging in almost the entire area of the syringe 1 (at least the portion where the hot melt is stored) and is held under pressure. Therefore, when the needle 4 is driven by the solenoid 61, the hot melt adhesive is discharged only while the needle valve is open.

[0061] Here, as the hot melt adhesive, for example, thermoplastic plastics such as polyurethane-based hot metal adhesives, ethylene vinyl acetate (EVA), polyolefins, synthetic rubbers, polyamides, and polyesters are mainly used. In the case of this embodiment, a PUR (Poly Urethane Reactive) - based hot melt adhesive is adopted. The PUR - based hot metal adhesive is a type that reacts with moisture (humidity) in the air or in paper and cures. Once it hardens, it does not soften even when heated and is an adhesive with high durability. On the other hand, for the equipment for applying it, it is likely to damage the seal member, and once it hardens, it cannot be re - softened by heat, so maintenance is not easy. For this reason, it is preferable to adopt this method in which the hot melt adhesive inside the syringe 1 is melted by heating from the outside of the syringe 1 and is injected by air pressure. Needless to say, the liquid material sealed in the syringe is not particularly limited to the above - mentioned hot melt adhesive, and other liquid materials such as adhesives in general or other substances can also be discharged.

[0062] The procedure for setting the syringe 1 to the valve body 20 in the hot melt adhesive discharging device configured as described above will be described.

[0063] First, attach the valve seat assembly 3 to the discharge part 10 at the tip of the syringe 1. Then, fit the syringe adapter 5 into the rear end opening 11, and insert the needle 4 into the syringe 1 through the central hole 14 of the syringe adapter 5 (see Fig. 1).

[0064] Here, the pre-filled syringe (which is distributed with hot melt adhesive pre-filled) is filled only with hot melt adhesive inside. Therefore, the pre-filled syringe filled with hot melt adhesive is first heated to a predetermined temperature in a pre-stage (i.e., pre-heating stage) until it melts, and then the valve seat assembly 3 and the needle 4 are attached to the syringe 1, and it is attached to the valve body 20 without taking much time from the pre-heating stage. At this point, the pre-filled syringe is attached in a state where the temperature drop after being heated in the pre-heating stage is not significant, thus sufficiently maintaining the molten state in which the needle 4 can be attached. After being attached to the valve body 20, the molten state can be maintained by maintaining the heating by the heating block 22. Incidentally, since the PUR-based hot melt adhesive has moisture-curing properties, if it is left in the air, it absorbs moisture in the air and the curing is promoted. However, since it is sealed in the syringe, kept at the melting temperature, and pressurized with dry discharge air, it is difficult for the curing to be promoted.

[0065] Next, after inserting the syringe 1 into the jacket 2, insert it into the valve body 20 together with the jacket 2 from the opening 33 on the front surface of the valve body 20 toward the nozzle catcher 25, and place the valve seat assembly 3 at the tip of the syringe 1 into the nozzle catcher 25 of the valve body 20, and store the syringe 1 in the syringe accommodation space 69 together with the jacket 2 (i.e., as the syringe set 6) (see Figs. 2 to 4). At this time, for the insertion of the syringe 1, the positioning member 64 of the valve body 20 is returned to the standby position, and the syringe accommodation space 69 directly below the positioning member 64 is open.

[0066] As shown in Fig. 13, the syringe set 6 placed in the syringe accommodation space 69 is automatically positioned approximately with respect to the valve body 20 by contacting the lock-up sleeve 67, that is, by contacting the guide portion 68. At this time, since the connect sleeve 16 is attracted to the yoke (magnet) 65 of the connecting member 63 on the valve body 20 side facing it, it is automatically centered and connected by magnetic force, and there is no risk that the syringe 1 will fall out of the valve body 20 even if the hand is released.

[0067] After the positioning of the syringe 1 with respect to the valve body 20 is completed, flushing air at a pressure higher than the air pressure when discharging the hot melt adhesive in the syringe is applied to the piston portion 66 of the lock-up sleeve 67 to lower the positioning member 64, fit the connection port 70 with the second plug portion 13 of the syringe adapter 5, and simultaneously complete the centering and connection between the valve body 20 side and the syringe 1 side and form a seal necessary to further push down the positioning member 64. Further, as the positioning member 64 descends, the O-ring on the peripheral surface of the connecting member 63 that seals the gap between the central hole of the positioning member 64 and the yoke magnet 65 comes off, and the air supplied to the space above the piston portion 66 leaks into the syringe 1. As a result, while the compressed air fills the syringe 1 under pressure, the positioning member 64 is further pushed down.

[0068] Thereby, the syringe 1 is set in a fixed position. Moreover, the syringe 1 is pressed against the valve seat assembly 3 by the positioning member 64 that continues to be applied with a downward force by the application of the air pressure for discharging the hot melt adhesive, and is held in a fixed position. After this or even before this, the lid 48 is fitted into the opening 33 on the front side of the heating block 22, and the jacket 2 is sandwiched between the semi-cylindrical portion 27 of the surrounding wall portion 26 (see Fig. 5). Further, the nozzle receiving portion 30 of the heating block 22, both side surfaces, and the lower portion of the lid 48 are covered with a protector 60 (see Fig. 8).

[0069] After the syringe 1 is set in place, the pneumatic pressure applied into the syringe 1 through the internal space of the lock-up sleeve above the piston portion 66 of the positioning member 64 by a control device (not shown) is switched to a pressure suitable for discharging the hot melt adhesive, in preparation for the discharging and applying operation of the hot melt adhesive. The hot melt adhesive in the heated and melted syringe 1 is discharged at the pressure applied in the syringe when the needle valve at the tip of the syringe is opened. Therefore, after adjusting the stroke amount of the needle 4 and setting the discharge time with the valve stroke adjustment mechanism 77 according to the required discharge amount, when the solenoid 61 is excited, the armature 62 is attracted and the needle 4 is lifted, opening the nozzle, and the hot melt adhesive in the syringe is discharged only while the needle 4 is being lifted.

[0070] Also, in the case of replacing the pre-packaged syringe 1 (or refilling the hot melt adhesive), the positioning member 64 is raised to disengage the connection port 70 from the plug portion 13 of the syringe adapter 5, and the restraint of the syringe 1 by the positioning member 64 is released. Also, by grasping the grip of the lid 48 and pulling it forward, the lid 48 is removed from the heating block 22. Since the magnetic coupling state between the coupling member 63 interlocked with the armature 62, the magnet, and the needle in the syringe is strong in the axial direction but relatively weak in the force for sliding in the lateral direction, the jacket 2 and the syringe 1 can be easily tilted by grasping the knob 7 of the jacket 2 and pulling it forward, and can be easily removed from the valve body 20 (see FIG. 3). Then, after removing the used syringe from the jacket 2 (see FIG. 1), the syringe adapter 5 is removed, the needle is pulled out, or the valve seat assembly 3 is removed as necessary (see FIG. 2). Then, the needle 4 and the valve seat assembly 3 are transferred to a new pre-packaged syringe in which the hot melt adhesive has been pre-melted on a press heating stage, and then the syringe 1 housed in the jacket 2 is loaded into the valve body 20 according to the above procedure. In the case of using a disposable pre-packaged syringe, even if carbide is generated and remains attached in the syringe, it is discarded as it is, so it is unlikely to cause nozzle clogging. For this reason, maintenance becomes easier.

[0071] Note that the above-described embodiments are merely examples of preferred embodiments of the present invention and are not limited thereto. Various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiments, a solenoid with excellent responsiveness is adopted as the actuator, but it is not particularly limited thereto. Actuators such as hydraulic or pneumatic fluid pressure cylinders, motors, diaphragms, etc., especially actuators using pneumatic pressure, can also be used. In this case, the actuator may directly drive the armature 62 in the junction box 21, or in some cases, the connecting member 63 may be directly driven. For example, when using a diaphragm, the connecting member 63 can be fixed to the diaphragm, and the lifting operation of the connecting member 63 can be controlled by applying a pressure change to the diaphragm. When using a fluid pressure cylinder, the piston itself can be used as the connecting member 63, or the connecting member 63 can be linked to the piston. That is, a part of the actuator may be used as the driven member. In addition, a piezoelectric element can also be used as the actuator.

Explanation of Signs

[0072] 1 Syringe 2 Jacket (heating and protection jacket) 3 Valve seat assembly 4 Needle 5 Syringe adapter 6 Syringe set 7 Knob 8 Spherical funnel part of syringe 9 Opening edge of syringe 10 Discharge part of syringe 11 Rear end opening of syringe 12 First plug part of syringe adapter 13 Second plug part of syringe adapter 14 Hole of syringe adapter 15 Flange part of syringe adapter 16 Connect sleeve 17 Impact rod 18 Impact stick 19 Jacket opening 20 Valve body 21 Junction box 22 Heating block 23 Platform 24 Bridge plate 25 Nozzle catcher 26 Enclosure part 27 Semi-cylindrical part 28 Linkage part 29 Hole 30 Nozzle receiving part 31 Block body 32 Step hole 33 (Enclosure part) opening 34 Groove 35 Heater module 36 Junction bush 37 Cover case 38 Recess (for housing the junction bush) 39 Power pin terminal 40 Detection signal pin terminal 41 Heater case 42 Temperature sensor 43 Depression 44 Spring 45 Thin film heat-resistant tape 46 Cartridge heater 47 Screw 48 Lid 49 Ball plunger 50 Handle 51 Inner peripheral surface of the lid 52 Side surface of the lid 53 Bottom surface of the lid 54 Bottom surface of the bridge plate 55 Shim ring 56 Through hole 57 Screw 58 Female thread 59 Air-relay block 60 Protector 61 Actuator 62 Armature 63 Connecting member 64 Positioning member 65 Magnet 66 Piston part 67 Lock-up sleeve 68 Guide part 69 Syringe accommodation space 70 Connecting port 71 Conductor pin 72 Conductor pin 73 POM washer 74 Stainless steel pipe 75 Spring 76 Communication passage 77 Valve stroke adjustment mechanism

Claims

1. A syringe that forms a needle valve with a needle inserted with a valve seat assembly attached to its tip opening, an actuator that drives the needle, and a heating source that heats a liquid material filled in the syringe, and a valve body that has a syringe accommodation space for accommodating the syringe. When the syringe is accommodated in the syringe accommodation space, the actuator and the needle are magnetically connected, and the liquid material in the heated syringe is discharged by the pressure applied in the syringe when the needle valve at the tip of the syringe is opened by the drive of the actuator. In the liquid material discharge device provided as follows: The syringe is housed in a heat-conductive jacket and attached to the valve body. The heating source of the valve body is a heating block composed of a nozzle receiving portion that supports the valve seat assembly at the tip of the syringe, a surrounding wall portion that has an opening at the front that enables the loading and removal of the jacket and surrounds the depth side of the jacket, and a block body that includes a heater. Moreover, the surrounding wall portion has a semi-cylindrical inner peripheral surface that is in close contact with the outer peripheral surface of the jacket, and a connecting portion composed of a pair of parallel flat surfaces that extend in the tangential direction from both ends of the semi-cylindrical inner peripheral surface. A heat-conductive lid that is housed between the pair of connecting portions and is thermally connected to the connecting portions forms a closed circular inner peripheral surface that is in close contact with the jacket between the semi-cylindrical inner peripheral surfaces, and the syringe is heated through the jacket by the heat transmitted to the surrounding wall portion and the lid. A liquid material discharge device characterized by the above.

2. The lid functions as a heat source / radiating surface that is heated by the heat of the heating block being transmitted because both side surfaces are in close contact with the connecting portion of the surrounding wall portion and the bottom surface contacts the nozzle receiving portion. The liquid material discharge device according to Claim 1.

3. The lid is provided with a heat-insulating handle and a combination of a ball plunger and a hole into which the ball of the ball plunger fits on at least one side surface facing the flat surfaces on both sides of the surrounding wall portion of the heating block, and is detachably provided on the heating block. The liquid material discharge device according to Claim 1 or 2.

4. The syringe is a cylindrical body having a spherical funnel portion and a discharge portion for attaching the valve seat assembly on the tip side, and the jacket is composed of a cylindrical portion covering the cylindrical body portion of the syringe and a frustum-shaped cylindrical body surrounding the spherical funnel portion. The liquid discharge device according to any one of claims 1 to 3, characterized in that the jacket and the syringe are in a fitting state where they can be inserted and removed, and the syringe is heated through the jacket.

5. The liquid discharge device according to any one of claims 1 to 4, characterized in that the heater is a heater module inserted into a groove or a hole provided in the block body of the heating block.

6. In the heater module, a temperature sensor is covered and attached to the surface of the heater case in contact with the heating block by a thin film heat-resistant tape, a recess is provided on the surface of the heater case under the temperature sensor, and an elastic member is housed therein. The liquid discharge device according to claim 5, characterized in that the temperature sensor is constantly biased so as to press against the heating block.

Images