Liquid material discharge device, and application device and application method therefor

A liquid material discharge device and method capable of suppressing generation of bubbles caused with a rod raising operation in a negative pressure environment. In a liquid material discharge device used in a negative pressure space and including a storage container; a compressed-gas supply source pressurizing the storage container; a nozzle having a discharge flow path; a reciprocating valve rod; an actuator driving the valve rod; a valve seat having a communication hole that is communicated with the discharge flow path; and a discharge control device controlling the actuator to open and close the communication hole by a tip of the valve rod, the discharge control device controls an acceleration time Au in rising of the valve rod by the actuator to be held within a range of 2 to 300 [ms], thus preventing generation of bubbles caused with the rising of the valve rod.

TECHNICAL FIELD

The present invention relates to a device and a method for discharging a liquid material in a negative pressure environment. In this Description, it is assumed that the term “negative pressure environment” includes a vacuum environment.

BACKGROUND ART

If bubbles are present in a liquid resin (liquid material) in a step (such as potting or underfilling) of applying the liquid material to a substrate to which a semiconductor component and so on are mounted, various adverse influences occur; for example, a discharge amount varies, a shape and a position of the applied liquid material are not constant (namely, drawing lines become disordered), the liquid material is scattered because the bubbles are ejected at the same time as when the liquid material is discharged, and the extra liquid material adheres to the surroundings of a discharge port of a nozzle.

As one example of methods for removing the above-mentioned adverse influences of the bubbles, there is known a method of placing the liquid material in a vacuum environment for degassing. According to the most general degassing method, prior to starting work, a container (syringe) containing the liquid material and actually used in the work is put as it is into another enclosed container, and the enclosed container is evacuated into a vacuum state for degassing of the liquid material. As for another method, there is proposed an application device having an inner space in which application of the liquid material is performed, the inner space being formed as an enclosed space and evacuated into a vacuum state for degassing of the liquid material.

For example, Patent Document 1 discloses a liquid material application device including a storage-discharge unit that stores a liquid material and discharges the liquid material through a discharge port, and applying the liquid material to an application target, wherein the application device further includes an application space surrounding at least the storage-discharge unit and the application target, and an evacuation system evacuating the application space into a negative pressure state, and wherein the liquid material is discharged toward the application target from the storage-discharge unit while the application space is held in the negative pressure state.

Patent Document 2 discloses a vacuum application device including a vacuum chamber in which a target product for application of a liquid resin is disposed, and applying the liquid resin in a vacuum state to a predetermined position of the application target product from a dispenser that is a supply source of the liquid resin, wherein the vacuum chamber containing the application target product is constituted by a first container portion containing and supporting the application target product, and a second container portion to which a nozzle of the dispenser is attached, wherein the first container portion and the second container portion are constituted to be relatively movable in an X-Y plane without breaking an airtight state of the vacuum chamber, and wherein an X-Y driver moving at least one of the first and second container portions in the X-Y plane and causing a relative planar positional relation between the application target product and the nozzle to be variable is installed outside the vacuum chamber.

CITATION LIST

Patent Documents

SUMMARY OF INVENTION

Technical Problem

In a discharge device including a reciprocating valve rod (plunger), when application work is performed using a discharge device disposed in a negative pressure space, a problem arises in that liquid pressure near a tip of the valve rod reduces and bubbles generate with an operation of raising the valve rod. If the bubbles generate near the tip of the valve rod, the above-mentioned problems occur; for example, the drawing lines become disordered and the liquid material is scattered at the time of discharge due to the presence of the bubbles.

An object of the present invention is to provide a liquid material discharge device and method capable of suppressing generation of bubbles caused with the operation of raising a valve rod in a negative pressure environment.

Another object of the present invention is to provide a liquid material discharge device and method capable of solving the problem of leakage of a liquid material, which may occur as a result of insufficient closing by a tip of the valve rod due to wear of the tip of the valve rod or a valve seat.

Solution to Problem

The present invention provides, according to a first aspect, a liquid material discharge device used in a negative pressure space, the liquid material discharge device comprising a storage container storing a liquid material, a compressed-gas supply source pressurizing the storage container, a nozzle having a discharge flow path, a reciprocating valve rod, an actuator driving the valve rod, a valve seat having a communication hole that is communicated with the discharge flow path, and a discharge control device controlling the actuator to open and close the communication hole by a tip of the valve rod, wherein the discharge control device controls an acceleration time Auin rising of the valve rod by the actuator to be held within a range of 2 to 300 [ms], thus preventing generation of bubbles caused with the rising of the valve rod.

In the above liquid material discharge device, the discharge control device may control a target speed V1in the rising of the valve rod by the actuator to be held within a range of 0.2 to 30 [mm/s].

In the above liquid material discharge device, the discharge control device may control an acceleration time Adin lowering of the valve rod by the actuator to be held within a range of 2 to 300 [ms]. In this case, the discharge control device may set the acceleration time Auin the rising of the valve rod and the acceleration time Adin the lowering of the valve rod by the actuator to be the same.

In the above liquid material discharge device, the actuator may be driven by using, as a drive source, a motor capable of controlling an advanced position of the valve rod with the discharge control device. In this case, the actuator may be driven by using, as the drive source, one selected from among a stepping motor, a servomotor, and a linear motor. Additionally, the liquid material discharge device may further comprise a position detection mechanism detecting that the tip of the valve rod is at a valve-seat closing position.

The present invention provides, according to a second aspect, a liquid material discharge device comprising a storage container storing a liquid material, a compressed-gas supply source pressurizing the storage container, a nozzle having a discharge flow path, a reciprocating valve rod, an actuator driving the valve rod, a valve seat having a communication hole that is communicated with the discharge flow path, and a discharge control device controlling the actuator to open and close the communication hole by a tip of the valve rod, wherein the liquid material discharge device further comprises a position detection mechanism detecting that the tip of the valve rod is at a position closing the valve seat.

In the above liquid material discharge device according to the second aspect, the actuator may be driven by using, as a drive source, a motor capable of controlling an advanced position of the valve rod with the discharge control device. In this case, the actuator may be driven by using, as the drive source, one selected from among a stepping motor, a servomotor, and a linear motor.

In the above liquid material discharge device including the position detection mechanism, the position detection mechanism may comprise a slide member connected to the actuator, a slider connected to the slide member, a sensor mechanism detecting that the slide member is at a predetermined position, a rod conjunction member connected to the valve rod and arranged in contact with the slide member in a separable manner, and an elastic member applying biasing force to keep the rod conjunction member and the slide member contacted with each other in a separable manner, wherein, when force acting to further advance the valve rod is applied by the actuator after the valve rod has come into contact with the valve seat, the slide member is moved downward away from the rod conjunction member, and the tip of the valve rod being at the position closing the valve seat is detected by detecting the downward movement of the slide member with the sensor mechanism.

In the above liquid material discharge device including the rod conjunction member, the rod conjunction member may be connected to the slider, and the elastic member may be a tension coil spring coupling the rod conjunction member and the slide member. In this case, the elastic member may have tensile force Pi equivalent to force that is able to move the rod conjunction member and the slide member when the valve rod and the valve seat are not in contact with each other.

In the above liquid material discharge device including the rod conjunction member, the slide member may have a top surface including a first through-hole through which the valve rod is inserted, and a bottom surface including a second through-hole through which the valve rod is inserted, the rod conjunction member and the elastic member may be arranged between the top surface and the bottom surface of the slide member, and the elastic member may keep the rod conjunction member contacted with the top surface or the bottom surface of the slide member in a separable manner. In this case, the liquid material discharge device may further comprise a fixing member through which the valve rod is inserted and which fixedly holds the rod conjunction member, and the elastic member may be a compression coil spring through which the valve rod is inserted. Additionally, the elastic member may have repulsive force Pii equivalent to force that is required to move the valve rod, the rod conjunction member, and the fixing member.

The above liquid material discharge device may further comprise a first guide member through which the valve rod is inserted, and which guides straight movement of the valve rod, and a second guide member through which the valve rod is inserted, and which guides the straight movement of the valve rod at a position lower than the first guide member. In this case, the liquid material discharge device may further comprise a third guide member through which the valve rod is inserted, and which guides the straight movement of the valve rod at a position lower than the second guide member.

The present invention further provides an application device comprising the above liquid material discharge device, a worktable on which a workpiece is to be placed, a relative driving device moving the liquid material discharge device and the worktable relatively to each other, a cover constituting a negative pressure space in which the liquid material discharge device, the worktable, and the relative driving device are arranged, a depressurization device producing negative pressure inside the cover, and a drive control device controlling the relative driving device.

In the above application device, the depressurization device may be a vacuum pump.

The present invention still further provides an application method using the above application device, wherein the liquid material is applied onto the workpiece while the workpiece and the liquid material discharge device are moved relatively to each other in a state that an inner space of the cover is held under negative pressure by the depressurization device.

In the above application method, the inner space of the cover may be substantially under a vacuum.

Advantageous Effects of Invention

According to the present invention, since generation of bubbles caused with the operation of raising the valve rod is suppressed, it is possible to avoid the problems, for example, that the drawing lines become disordered and the liquid material is scattered at the time of discharge.

Since the liquid material is fed under pressure using the compressed gas and the communication hole is opened and closed by the valve rod, the liquid material can be stably discharged at a high speed (high flow rate) with good response.

Furthermore, in the present invention including the position detection mechanism, closing by the tip of the valve rod can be reliably ensured even when wear of the valve rod tip or the valve seat occurs.

DESCRIPTION OF EMBODIMENTS

Embodiments for carrying out the present invention will be described below.

First Embodiment

A discharge device1according to a first embodiment of the present invention is a discharge device of the type that a liquid material is discharged by opening a communication hole7in a valve seat6with an operation of raising a valve rod21, and that discharge of the liquid material is stopped by closing the communication hole7with an operation of lowering the valve rod21. The discharge device1is used in a negative pressure space in a state mounted to an application device101. The discharge device1can prevent generation of bubbles by adjusting a speed and an acceleration of the valve rod21by controlling an operation of an electric actuator28with a discharge control device33. The discharge device1includes a position detection mechanism34for detecting a position where the valve rod21comes into contact with the valve seat6. Thus, the communication hole7in the valve seat6can be reliably closed even when wear of the valve rod21or the valve seat6occurs.

In the following, a structure of the discharge device1is first described, and an operation of the discharge device1is then described.

FIG. 1is a partial sectional side view of the discharge device1according to the embodiment of the present invention.FIG. 2is a sectional view taken along a line A-A inFIG. 1when viewed in a direction denoted by arrow, andFIG. 3is a sectional view taken along a line B-B inFIG. 1when viewed in a direction denoted by arrow. In the following description, the side including the actuator28is called the “upper side”, and the side including the nozzle3is called the “lower side” in some cases. Moreover, a viewing point ofFIG. 1is expressed by “when viewed from front”, and a viewing point ofFIGS. 2 and 3is expressed by “when viewed from side” in some cases.

The discharge device1includes a storage container (syringe)2, a nozzle3, a nozzle attachment member5, the valve seat6, a body lower member10, and the position detection mechanism34.

The storage container2used in the first embodiment is a general resin-made syringe having a flange9at an upper end and an inner tube8at a lower end. The valve rod21is inserted through the storage container2, and an inner space of the inner tube8defines a rod-tip insertion hole. The nozzle attachment member5, the valve seat6, and the nozzle3are attached to the inner tube8.

The nozzle3is a pipe-like member, and an inner space of the nozzle3defines a discharge flow path4. The nozzle attachment member5is screwed into the lower end of the syringe2, whereby the syringe2and the discharge flow path4in the nozzle3are communicated with each other via the valve seat6.

The nozzle attachment member5is a cylindrical member, and it has, in a bottom portion, a through-hole into which the nozzle3is inserted.

The valve seat6is fitted to a recess in the nozzle attachment member5, and is fixedly held in a state sandwiched between the nozzle attachment member5and the inner tube8at the lower end of the syringe2. The valve seat6is positioned at a lowermost edge of the syringe2, and it has the communication hole7for communicating the syringe2and the discharge flow path4in the nozzle3with each other.

The body lower member10is a plate-like member arranged at a lower end of a head cover47in which the actuator28and upper and lower slide blocks (37,38) are accommodated. A flange support member11having a hook-like shape is disposed at a lower surface of the body lower member10, and it holds the flange9formed at the upper end of the syringe2. An insertion portion12having a circular columnar shape and having substantially the same diameter as an inner diameter of the syringe2is provided at a lower surface of the body lower member10, and is fitted into the syringe2. A sealing member B16is disposed around an outer periphery of the insertion portion12to prevent leakage of compressed gas. A through-hole13through which the valve rod21is inserted is vertically formed at centers of the body lower member10and the insertion portion12.

An annular sealing member A15to prevent leakage of the compressed gas is disposed near an upper end of the through-hole13, and the valve rod21is inserted through the sealing member A15. Because an inner diameter of the through-hole13is greater than a diameter of the valve rod21, an outer peripheral surface of the valve rod21contacts only the sealing member A15and does not contact an inner peripheral surface of the through-hole13. A seal retainer17for fixedly holding the sealing member A15is provided at the upper end of the through-hole13. While, in this embodiment, the upper end of the through-hole13forms a projected portion14that is projected upward from the body lower member10by a distance corresponding to both the sealing member A15and the seal retainer17, the present invention is not limited to that configuration. In another example, the sealing member A15may be disposed such that the body lower member10has a flat upper surface.

A compressed-gas flow path18is communicated with a lateral surface of the through-hole13, thus allowing the compressed gas supplied through the compressed-gas flow path18to be introduced into the syringe2. The compressed-gas flow path18is a flow path formed inside the body lower member10and having an L-like shape in cross-section, and is opened at an upper surface of the body lower member10. A gas supply joint19having a compressed-gas supply port is fitted to the opening of the compressed-gas flow path18. The compressed-gas, such as atmosphere gas, nitrogen gas, or carbon dioxide gas, is supplied to the gas supply joint19from a compressed-gas supply source (not illustrated) via a compressed-gas supply pipe20. The liquid material (having viscosity of, for example, 0.1 to 5 Pa·S) stored in the syringe2is pressurized to, for example, 300 to 500 kPa by the supplied compressed gas. While, in this embodiment, the compressed-gas flow path18is bent inside the body lower member10and is opened at the upper surface of the body lower member10, the present invention is not limited to that configuration. The compressed-gas flow path18may be opened at a lateral or lower surface of the body lower member10.

A lower end portion of the valve rod21extends while penetrating the through-hole13and is positioned inside the syringe inner tube8(i.e., near the valve seat6), and an upper end portion of the valve rod21extends upward of the upper surface of the body lower member10and reaches a position facing the actuator28. The lower end portion of the valve rod21has a smaller width (diameter) than the syringe inner tube8, and a gap between an inner wall of the inner tube8and a lateral peripheral surface of the valve rod21is filled with the liquid material. The valve rod21in this embodiment is constituted by a step-formed rod having a smaller diameter near its lower end, but the present invention is not limited to such an example. The valve rod21may have a smaller diameter portion depending on the diameter of the communication hole7in the valve seat6in some cases, and may have no smaller diameter portion in other cases. That type of valve rod is also called a valve needle or a plunger.

The valve rod21is connected at its upper portion to the actuator28via rod holders (22,23), and is linearly moved in a reciprocal manner by the action of the actuator28.

The actuator28is attached, in an upper space within the head cover47, to an actuator attachment plate29coaxially with the valve rod21. The actuator attachment plate29is bridged between upper ends of two actuator support plates30that are disposed in opposing relation with both an actuator rod31and the valve rod21positioned therebetween. While, in this embodiment, the actuator28and the valve rod21are arranged coaxially with each other, axes of the actuator28and the valve rod21may be not coaxial in another embodiment.

The actuator rod31operated to be capable of extending and contracting penetrates through the actuator attachment plate29and further extends downward. A lower end portion of the actuator rod31is joined to a horizontal portion26aof a drive transmission member by a fixing member27. The drive transmission member26is a member having an L-like shape when viewed from front, and the horizontal portion26ais connected to the lower end portion of the actuator rod31. A vertical portion of the drive transmission member26, which is perpendicular to the horizontal portion26a, is coupled to the lower slide block38.

For example, a stepping motor, a servomotor, or a linear motor can be used as the actuator28. Using such a motor as the actuator28is to control a speed and an acceleration in operation of the valve rod21driven by the actuator28. In this embodiment, the actuator28is constituted by a stepping motor equipped with a resolver, and the speed and the acceleration in operation of the valve rod21are controlled. A control wiring32for communication with the discharge control device33, which controls operation of the actuator28, is connected to an upper end portion of the actuator28.

The position detection mechanism34is mainly constituted by the two slide blocks (37,38), an elastic member42, a sensor43, and a detection plate45. A slide rail36is mounted, in a state extending vertically, to a slide attachment plate39having an L-like shape in a sectional view such that the two slide blocks (37,38) are movable over the slide rail36(seeFIG. 1). With the two slide blocks (37,38) moving over the slide rail36, a lower surface of the upper slide block37and an upper surface of the lower slide block38are in positional relation coming into contact with each other or departing away from each other. The upper slide block37functions as a rod conjunction member that is moved in conjunction with the valve rod21, and that departs away from the lower slide block38by the action of predetermined force.

An upper portion of a coupling member25is coupled to the upper slide block (rod conjunction member)37, and the upper slide block37is connected to the valve rod21via the coupling member25. The coupling member25has a “C”-like shape or “[”-like shape when viewed from side, and the lower slide block38is arranged in a recess formed in the coupling member25(seeFIG. 3). The rod holder B23for holding the valve rod21is attached to a lower end of the coupling member25. The rod holder A22is detachably fixed to the rod holder B23by fasteners24.

The valve rod21is fixedly held by tightening the fasteners24and grasping the valve rod21in a state sandwiched between the two rod holders (22,23). Ordinary screws are used as the fasteners24in this embodiment, but another type of fastening part may also be used. With the above-described structure, the valve rod21can be easily attached in a detachable manner, and maintenance work is facilitated.

An L-shaped attachment plate44to which the sensor43is fixed is attached to an upper end of the upper slide block37. A photosensor is used as the sensor43in this embodiment, but another type of sensor, such as a fiber sensor, a photoelectric sensor, or a vicinity sensor (of high-frequency oscillation type or electrostatic type), may also be used.

The drive transmission member26connected to the actuator rod31and having an L-like shape when viewed from front is attached to a lateral surface of the lower slide block38. The detection plate45is mounted to a lateral (front) surface of the lower slide block38perpendicular to the lateral surface thereof to which the drive transmission member26is attached. The detection plate45has, in an upper portion, a folded portion45ato actuate the sensor43(seeFIG. 3). In this embodiment, the sensor43detects movement of the valve rod21in response to motion of the folded portion45aintercepting an optical axis of the photosensor43or allowing light to pass therethrough.

An upper pin40is disposed at a front surface of the upper slide block37, and a lower pin41is disposed at a front surface of the lower slide block38. The elastic member (spring)42is disposed between the two pins (40,41). The elastic member42is a tension coil spring and has tensile force Pi equivalent to the force that is required to move the upper slide block37and the other associated components (including the coupling member25, the valve rod21, and the sensor43) over the slide rail36. The elastic member42acts to keep the upper slide block37and the lower slide block38contacted with each other.

The components on the upper side of the body lower member10are covered with the head cover47. This is intended to protect an operator from touching movable components, and to prevent release of dust from the movable components and intrusion of dust to the movable components.

Operations of the discharge device1according to the embodiment of the present invention will be described below with reference toFIGS. 4, 5 and 6.

First, an operation of raising the valve rod21from a position where the lower end of the valve rod21contacts the valve seat6is described with reference toFIG. 4. When the actuator28is operated to contract the actuator rod31(as denoted by numeral48), the lower slide block38rises (as denoted by numeral49) together with the drive transmission member26. Since the upper surface of the lower slide block38contacts the lower surface of the upper slide block37, the rising of the lower slide block38pushes up the upper slide block37(as denoted by numeral50). Therefore, the coupling member25coupled to the upper slide block37and the rod holders (22,23) coupled to the lower end of coupling member25rise, thus causing the valve rod21held by the rod holders (22,23) to rise (as denoted by numeral51). With rising of the valve rod21, as illustrated inFIG. 4, the lower end of the valve rod21departs away from the valve seat6, and the liquid material having passed through the discharge flow path4flows out from the discharge port.

An operation of lowering the valve rod21until the lower end of the valve rod21contacts the valve seat6is now described with reference toFIG. 5. When the actuator28is operated to extend the actuator rod31downward (as denoted by numeral52), the lower slide block38lowers together with the drive transmission member26(as denoted by numeral53). Since the lower slide block38is coupled to the upper slide block37by the spring42, the upper slide block37also lowers by the action of the spring42(as denoted by numeral54). Here, the strength (Pi) of the spring42is set to be equivalent to the force that is required to move the upper slide block37and the other associated components (including the coupling member25, the valve rod21, and the sensor43) over the slide rail36. Therefore, the spring42is substantially not extended, and the upper slide block37is moved in a state kept contacted with the lower slide block38. With lowering of the upper slide block37, the coupling member25and the rod holders (22,23) coupled to the lower end of coupling member25also lower, thus causing the valve rod21held by the rod holders (22,23) to lower (as denoted by numeral55). Accordingly, as illustrated inFIG. 5, the lower end of the valve rod21comes into contact with the valve seat6, and the communication between the discharge flow path4and the storage container2is cut off, whereby the liquid material is stopped from flowing out from the discharge port. Ordinary discharge work is performed by repeating the raising operation and the first lowering operation.

A lowering operation of bringing the position of the valve rod21into a safely closed position is now described with reference toFIG. 6. Even after the lower end of the valve rod21has come into contact with the valve seat6, the actuator rod31continues to extend downward with further extension of the actuator28(as denoted by numeral56). With lowing of the drive transmission member26, the lower slide block38also lowers (as denoted by numeral57), but lowering of the upper slide block37is limited by the valve rod21having come into contact with the valve seat6. Therefore, as the lower slide block38lowers, the folded portion45aof the detection plate coupled to the lower slide block38lowers and departs away from the sensor43. Upon detecting such a state, the sensor43sends a detection signal to the discharge control device33. The discharge control device33stores, as an initial detected position (or a contact position), a position where the folded portion45aof the detection plate departs away from the sensor43.

When only the lower slide block38lowers in the state that the lower end of the valve rod21contacts the valve seat6as described above, the spring42coupling the upper slide block37and the lower slide block38is extended to generate force acting to pull down the upper slide block37. That force acts as force pressing the valve rod21against the valve seat6via coupling member25, thereby bringing the actuator rod31into the safely closed position where it is further lowered from the initial detected position by a predetermined distance. Thus, since the discharge control device33causes the valve rod21to be positioned at the safely closed position, closing of the valve seat6by the valve rod21is ensured. In this embodiment, the safely closed position is set to a position apart by 1 mm, for example, from the initial detected position. The above-described second lowering operation is performed when there is a long time until the next discharge work (i.e., in a long standby mode).

While this embodiment is designed so as to further lower the valve rod21from the initial detected position where the folded portion45aof the detection plate departs away from the sensor43, the position of the detection plate45may be adjusted such that the detection plate45departs away from the sensor43at a position where the spring42is extended by a certain length after the lower end of the valve rod21has come into contact with the valve seat6and then has further lowered. The position detection mechanism34may also be constituted without using the sensor43. The contact position of the valve rod21may be detected, for example, by detecting a rotation angle or a movement amount of a motor shaft with the aid of an encoder, for example, which is attached to the motor for the actuator28, and by utilizing an advanced or retracted position of the valve rod21, which is obtained from the detected rotation angle or movement amount.

In this embodiment, a drop of liquid pressure caused near the lower end of the valve rod21and generation of bubbles due to the drop of liquid pressure are suppressed by controlling a rising speed and an acceleration (acceleration and deceleration times in this embodiment) in the operation of raising the valve rod21by the actuator28.

FIG. 17is a graph (diagram) referenced to explain acceleration and deceleration times when the valve rod is raised. A vertical axis V represents speed, and a horizontal axis t represents time. When t is zero, the valve rod21is at the initial detected position (contact position), and the upward moving speed V is zero. InFIG. 17, A denotes an acceleration time, and B denotes a deceleration time. If a rising-mode acceleration time Auuntil reaching a target speed V1is smaller than a certain value, the problem of bubble generation occurs. As a result of conducting discharge experiments using an underfill material, it has been confirmed that the liquid material can be discharged without generating bubbles under discharge conditions that the target speed V1is, for example, 0.2 to 30 [mm/s] (preferably 0.5 to 20 [mm/s]) and the rising-mode acceleration time Auis, for example, 2 to 300 [ms] (preferably 5 to 200 [ms]). In a related-art device, the liquid material is discharged under conditions that the target speed V1is about 10 times the above-mentioned values and the acceleration time A is about 1/10 time the above-mentioned values.

A rising-mode deceleration time Buis set to the same value as the rising-mode acceleration time Au, or a value within the allowable range (e.g., 2 to 300 [ms]) of the acceleration time.

A lowering-mode acceleration time Adand a lowering-mode deceleration time Bdin the operation of lowering the valve rod21are set to the same values as the rising-mode acceleration time Auand the rising-mode deceleration time Bu, respectively, or values within the allowable range (e.g., 2 to 300 [ms]) of the acceleration time. The lowering operation as quick as in the related-art device is not preferable because of causing an uncontrollable increase of the discharge amount.

A liquid material discharge operation including the above raising operation and lowering operation is as follows.

First, the compressed-gas is supplied from the compressed-gas source to the gas supply joint19via the compressed-gas supply pipe20, thus pressurizing the liquid material stored in the syringe2via the compressed-gas flow path18and the through-hole13. When the actuator28receives a discharge start signal from the discharge control device33, the valve rod21is raised in accordance with the controlled speed and the controlled acceleration and deceleration times, whereby the liquid material is discharged from the discharge port. After the lapse of a time corresponding to the desired discharge amount, upon receiving a discharge end signal from the discharge control device33, the actuator28lowers the valve rod21and closes the communication hole7in the valve seat6by the lower end of the valve rod21(first lowering operation). The foregoing is one cycle of basic discharge operation. Pressure of the supplied compressed-gas, a rising distance of the valve rod21, a valve open time, etc. are appropriately set depending on physical properties and states (such as viscosity and temperature) of the liquid material used. The diameter and length of the nozzle3, the diameter of the communication hole7in the valve seat6, etc. can also be changed depending on conditions.

As described above, in the discharge device1according to this embodiment in which the liquid material is discharged by moving the valve rod21up and down to open and close the communication hole7in the valve seat6, which is communicated with the discharge flow path4of the nozzle3attached to the end of the syringe2, the generation of bubbles in the inner tube8(i.e., in the rod-tip insertion hole) due to a pressure drop, which is caused with rising of the valve rod21, can be avoided by using the electric actuator28capable of adjusting the speed and the acceleration (or the acceleration and deceleration times) in the rising and lowering movements of the valve rod21, and by appropriately controlling those parameters. As a result, it is possible to solve the problems, for example, that the discharged liquid material is scattered and the drawing lines become disordered due to the presence of the bubbles in the liquid material.

Furthermore, since the discharge device1has the structure utilizing the existing syringe and allowing the valve rod21to be easily attached and detached, maintenance work, such as cleaning and assembly, is easy to carry out.

Moreover, since the liquid material is fed under pressure using the compressed gas and the opening and closing operations are performed by the valve rod21, the liquid material can be stably discharged at a high speed (high flow rate) with good response.

In addition, with the provision of the position detection mechanism34, closing of the communication hole7in the valve seat6by the lower end of the valve rod21can be reliably ensured. When wear of the valve rod21or the valve seat6occurs, there is a risk that the communication hole7cannot be positively closed and the liquid material may leak. On the other hand, when the valve rod21is excessively pressed against the valve seat6, there is a risk that the valve seat6may be broken. In the first embodiment, since the contact position between the lower end of the valve rod21and the valve seat6is accurately detected by the position detection mechanism34, the risk of leakage of the liquid material is eliminated even after long-time use.

FIG. 7is a schematic perspective view of an application device101including the discharge device1according to the first embodiment.

The application device101according to the first embodiment includes, on a base102, a table104on which a workpiece103, i.e., an application target, is to be placed, as well as an X driving device105, a Y driving device106, and a Z driving device107for moving the above-described discharge device1relatively to the workpiece103. The relative driving devices (105,106,107) are movable in directions denoted by numerals108,109and110, respectively. The discharge control device33for controlling the above-described operations of the discharge device1and a drive control device111for controlling operations of the driving devices (105,106,107) are disposed inside the base102. A space above the base102is surrounded by a cover112denoted by dotted lines, and an inner space of the cover can be brought into a negative pressure environment using a not-illustrated vacuum pump, for example. The cover112may include a door allowing an access to the inner space. Although the inner space is brought into the negative pressure environment in this embodiment, the application work may be performed under atmospheric pressure.

Second Embodiment

A liquid material discharge device1according to a second embodiment, illustrated inFIG. 8, is mainly different from the first embodiment in that the storage container2is constituted by, instead of a syringe into which the valve rod21is inserted, a syringe connected using an extension member60. In the following, different points from the first embodiment are mainly described, and description of common elements is omitted in some cases.

A valve rod driving system (i.e., components above the body lower member10) inside the head cover47is similar to that in the first embodiment. With the actuator28vertically reciprocating the actuator rod31, the valve rod21is also vertically reciprocated via the drive transmission member26, the upper slide block37, and the lower slide block38.

The body lower member10in the second embodiment is different from that in the first embodiment in including an extended portion58continuously extended downward. The body lower member10and the extended portion58may be constituted integrally with each other, or constituted by joining different members to each other.

The body lower member10and the extended portion58have a through-hole13extending in the vertical direction. A lower end of the through-hole13is fluidly connected to a liquid chamber59that is wider than the through-hole13formed in the extended portion58. Annular sealing members C64and D65for preventing leakage of the liquid material are arranged in the through-hole13.

The liquid chamber59is constituted by a large-diameter space and a small-diameter space positioned under the large-diameter space, and a lower half portion of the valve rod21is arranged in the liquid chamber59. More specifically, an end part of a large-diameter portion of the valve rod21is arranged in the large-diameter space of the liquid chamber59, and an end part of a small-diameter portion of the valve rod21is arranged in the small-diameter space of the liquid chamber59. The large-diameter space and the small-diameter space constituting the liquid chamber59are wider than the end parts of the large-diameter and small-diameter portions of the valve rod21, respectively. Therefore, when the valve rod21is vertically reciprocated, the lateral peripheral surface of the valve rod21does not contact an inner wall of the liquid chamber59. In the second embodiment, the small-diameter space of the liquid chamber59, which is positioned inside a tip58aof the extended portion, constitutes the rod-tip insertion hole.

The nozzle attachment member5is screwed into the tip58aof the extended portion. The valve seat6is arranged in an inner space of the nozzle attachment member5and is fixedly sandwiched between the tip58aof the extended portion and the nozzle attachment member5.

One end of a lateral flow path59ais communicated with a lateral surface of the large-diameter space of the liquid chamber59. The other end of the lateral flow path59ais communicated with a liquid supply port62in the extension member60attached to lateral surface of the extended portion58.

The extension member60is a block-like member including a liquid supply flow path61of which one end constitutes the liquid supply port62. A liquid supply joint63is arranged at the other end of the liquid supply flow path61. The liquid supply joint63is fluidly connected to the storage container (syringe)2to which the liquid material pressurized by the compressed-gas supply source (not illustrated) is supplied. The syringe2may be connected to the liquid supply joint63via a liquid feed tube, or directly coupled to the liquid supply joint63. In the second embodiment, the syringe2is easily replaced because the valve rod21is not inserted into the syringe2.

Other components are the same as those in the first embodiment, and hence description of those components is omitted.

Also in the discharge device1according to the second embodiment, a drop of liquid pressure caused near the lower end of the valve rod21and generation of bubbles due to the drop of liquid pressure can be suppressed by controlling the rising speed and the acceleration (acceleration and deceleration times in this embodiment) of the valve rod21operated by the actuator28.

The discharge operation is similar to that in the first embodiment, and hence description of the discharge operation is omitted. The discharge device1according to the second embodiment is also mounted to the application device101and used in a negative pressure environment as in the first embodiment.

The above-described discharge device1according to the second embodiment can also suppress the generation of bubbles by controlling the rising speed and the acceleration of the valve rod21as in the first embodiment.

Furthermore, since the existing syringe2is connected using the extension member60, maintenance work is easy to carry out.

Moreover, since the valve rod21is not inserted into the syringe2, the length of the valve rod21can be shortened, and wobbling of the lower end of the valve rod21can be reduced.

Third Embodiment

A liquid material discharge device1according to a third embodiment, illustrated inFIGS. 9 and 10, is mainly different from the first embodiment in that the discharge device includes an outer frame201, an inner frame218, a sensor43, and a detection plate45attached to the inner frame, and that the sensor43detects valve closing in accordance with vertical movement of the inner frame. In the following, elements common to the first embodiment are denoted by the same reference numerals, and description of those elements is omitted in some cases.

FIG. 9is a partial sectional front view of a discharge device according to a third embodiment.FIG. 10is a sectional view taken along a line C-C inFIG. 9when viewed in a direction denoted by arrow. The actuator side inFIG. 10is called a “rear side”, the side opposite to the actuator side relative to a central axis is called a “front side”, and right and left surfaces positioned between a rear surface and a front surface are called “lateral surfaces” in some cases.

The valve rod21in the third embodiment is a linear member having a length extending from a position near the valve seat6to a position near the actuator28, and is inserted through a first bushing208, a second bushing209, a rod conjunction member221, a first fixing member222, a second fixing member223, and an elastic member224.

The first bushing208and the second bushing209are tubular members for supporting the valve rod21while slidably contacting the outer peripheral surface of the valve rod21, and they function as guide members to prevent wobbling of the valve rod21. In other words, with guide of the first bushing208and the second bushing209, straight-moving stability of the valve rod21is improved, and the contact position between the lower end of the valve rod21and the valve seat6is prevented from displacing. Thus, the tip of the valve rod21and the communication hole7in the valve seat6are positioned just in alignment with each other, and liquid leakage does not occur.

A space above the body lower member10is covered with a not-illustrated cover as in the first embodiment.

Components (such as the storage container2, the nozzle3, and the valve seat6) included in the discharge device1according to the third embodiment and positioned under the body lower member10are similar to those in the discharge device1according to the first embodiment.

The body lower member10is a plate-like member including an insertion portion12projecting downward, a projected portion207projecting upward, and a second bushing insertion hole213into which the second bushing209extending vertically is disposed. The gas supply joint19is connected to one lateral surface of the body lower member10.

The second bushing insertion hole213penetrates through a center of the body lower member10from an upper surface of the projected portion207to a lower surface of the insertion portion12. A diameter of the second bushing insertion hole213is substantially equal to that of the second bushing209, but a portion of the second bushing insertion hole213closer to its lower end has a diameter smaller than that of the second bushing209(and greater than that of the valve rod21). A step formed by that portion supports the second bushing209. A second bushing retainer211for fixedly holding the second bushing209is disposed at an upper end of the second bushing insertion hole213.

A not-illustrated communication hole for communicating the inside of the syringe2and the compressed-gas flow path18with each other is formed in the insertion portion12, and the compressed gas is supplied into the syringe2through the communication hole. A sealing member214for preventing leakage of the compressed gas to the outside is disposed over an outer surface of the insertion portion12near its lower end.

The outer frame201having a substantially rectangular parallelepiped shape with an inner space is disposed above the body lower member10, and it includes a later-described position detection mechanism34.

A fitting hole202is formed in a lower portion of the outer frame201, and the projected portion207projecting from an upper surface of the body lower member10is fixedly fitted to the fitting hole202.

An extension portion204is provided on an upper surface of the outer frame201, and the first bushing208for supporting the valve rod21in a linearly movable manner is disposed in the extension portion204. A first bushing insertion hole212in communication with the inner space of the outer frame201is disposed in the extension portion204. As with the above-described second bushing insertion hole213, the first bushing insertion hole212is also constituted by a large-diameter portion and a small-diameter portion, and a step between the large-diameter portion and the small-diameter portion supports the first bushing208. A first bushing retainer210for fixedly holding the first bushing208is disposed at an upper end of the first bushing insertion hole212. An opening206through which the actuator rod31and an actuator support member215are to be inserted is formed in an upper portion of the outer frame201on the rear side of the extension portion204.

One lateral surface of the outer frame201(left lateral surface inFIG. 9, but it may be a right lateral surface without being limited to the left lateral surface) is opened, and an attachment plate44is disposed to cover the opened lateral surface over a certain size while forming an opening203. The sensor43constituting the position detection mechanism34is fixedly disposed on an inner surface of the attachment plate44. The sensor43in the third embodiment is a photosensor, but another type of sensor, such as a fiber sensor, a photoelectric sensor, or a vicinity sensor (of high-frequency oscillation type or capacitance type), may also be used as in the first embodiment. Details of detection operation will be described later.

The outer frame201is nearly entirely opened on the front side, and work for maintenance and adjustment can be performed through a front-side opening (seeFIG. 10).

A rear portion205of the outer frame201is projected up to a more rearward position than the body lower member10(seeFIG. 10). The actuator support member215in the form of a plate is disposed on the front (inner) side of the rear portion205. The actuator support member215extends from a position near a lower end of a slider216to a position above the extension portion204, and supports the actuator28above the outer frame201. In this embodiment, the actuator28is constituted by a stepping motor equipped with a resolver, and the speed and the acceleration in operation of the valve rod21are controlled. However, the actuator28may be constituted by another type of motor as in the first embodiment.

The slider216capable of moving over a slide rail217is disposed on the front side of the actuator support member215. The slider216is coupled to the actuator rod31and the inner frame218.

The inner frame218is slightly smaller than the outer frame201, and has a substantially rectangular parallelepiped shape with an inner space. The inner frame218is coupled to the slider216, and functions as a slide member moving together with the slider216.

The inner frame218is nearly entirely opened on the front side similarly to the outer frame201.

A first through-hole219is formed in an upper portion of the inner frame218, and a second through-hole220is formed in a lower portion of the inner frame218. The valve rod21extends to pass through both the through-holes (219,220). A diameter of the first through-hole219is greater than that of the valve rod21, thus allowing the valve rod21to vertically move through the first through-hole219in noncontact relation. The second fixing member223having a smaller diameter than the second through-hole220is inserted through the second through-hole220.

The rod conjunction member221is arranged in the inner space of the inner frame218, and the valve rod21is fixedly inserted through a through-hole in the rod conjunction member221. When the slider216is moved vertically, the inner frame218coupled to the slider216is moved together, whereby the valve rod21is also moved vertically via the rod conjunction member221.

The rod conjunction member221is fixed to the valve rod21in a state that the first fixing member222and the second fixing member223tightly sandwiches the rod conjunction member221from above and below. More specifically, threads are formed in the outer peripheral surface of the valve rod21in its portions to which the fixing members (222,223) are attached, and those threads can be meshed with threads formed in inner peripheral surfaces of the fixing members (222,223). Therefore, the rod conjunction member221can be fixed to a desired position by adjusting positions of the fixing members (222,223). The position of the rod conjunction member221is preferably adjusted such that, when the lower end of the valve rod21comes into contact with the valve seat6(namely, when it reaches the above-described contact position), a bottom surface of the rod conjunction member221comes into contact with an inner bottom surface (upper surface of the lower portion) of the inner frame218(as represented by a state illustrated inFIG. 9 or 10).

A method of fixing the rod conjunction member221is not limited to the above-described one. As in the first embodiment, the rod conjunction member221may be divided into two parts and fixed to the valve rod21by tightly sandwiching the valve rod21between the two parts from front and rear.

The elastic member224through which the valve rod21and the first fixing member222are inserted is disposed between the rod conjunction member221and a top surface of the inner frame218. One end of the elastic member224is abutted against the top surface of the inner frame218, and the other end of the elastic member224is abutted against an upper surface of the rod conjunction member221, thus biasing the valve rod21downward via the rod conjunction member221. A recess having substantially the same diameter as the elastic member224is formed in the upper surface of the rod conjunction member221, and an end portion of the elastic member224is fitted to the recess to be supported in a not-displaceable manner. Unlike this embodiment, a recess having substantially the same diameter as the elastic member224may be formed in the top surface of the inner frame218against which the upper end of the elastic member224is abutted. The elastic member224in this embodiment is a compression coil spring and has repulsive (compressive) force Pii equivalent to the force that is required to move the valve rod21, the rod conjunction member221, the first fixing member222, and the second fixing member223.

A detection plate45is disposed on an outer lateral surface of the inner frame218in opposing relation to the sensor43. As in the first embodiment, the detection plate45constitutes the position detection mechanism34in cooperation with the sensor43. Unlike this embodiment, the sensor43may be arranged on the outer lateral surface of the inner frame218, and the detection plate45may be disposed on the attachment plate44at a position opposing to the sensor43.

In the third embodiment, since the first bushing208, the elastic member224, the rod conjunction member221, the second bushing209, the valve seat6, and the nozzle3are disposed coaxially with a central axis225of the valve rod21, no moment load is applied to the valve rod21. Therefore, straight-moving stability of the valve rod21is improved, wobbling of the lower end of the valve rod21is reduced, and displacement of the contact position between the valve rod21and the valve seat6is reduced. In other words, the tip of the valve rod21can reliably close the communication hole7in the valve seat6, and liquid leakage does not occur in the valve-closed state.

Furthermore, the bushings (208,209) for supporting the valve rod21in a linearly movable manner are arranged not only in a central portion of the valve rod21(as represented by the second bushing209), but also in an end portion of the valve rod21(as represented by the first bushing208). That arrangement contributes to further improving the straight-moving stability of the valve rod21, reducing the wobbling of the lower end of the valve rod21, and reducing the displacement of the contact position between the valve rod21and the valve seat6.

In addition, the wobbling of the lower end of the valve rod21can be further reduced in some cases by setting a distance between from the first bushing208to the second bushing209substantially equal to a distance from the second bushing209to a valve-closed point (i.e., the contact point between the end of the valve rod21and the valve seat6).

Operations of the discharge device1according to the third embodiment will be described below with reference toFIGS. 11, 12 and 13.

First, an operation of raising the valve rod21from a position where the lower end of the valve rod21contacts the valve seat6is described with reference toFIG. 11. When the actuator28is operated to contract the actuator rod31, the slider216connected to the actuator rod31rises (as denoted by numeral226). With rising of the slider216, the inner frame218fixed to the slider216rises together (as denoted by numeral227). With rising of the inner frame218, the inner bottom surface of the inner frame218causes the rod conjunction member221to rise together (as denoted by numeral228), and hence the valve rod21held by the rod conjunction member221also rises (as denoted by numeral229). Upon the lower end of the valve rod21departing away from the valve seat6, the liquid material having passed through the discharge flow path4flows out from the discharge port.

An operation of lowering the valve rod21until the lower end of the valve rod21contacts the valve seat6is now described with reference toFIG. 12. When the actuator28is operated to extend the actuator rod31downward, the slider216lowers (as denoted by numeral230). With lowering of the slider216, the inner frame218fixed to the slider216lowers together (as denoted by numeral231), thus causing the rod conjunction member221to lower via the elastic member224(as denoted by numeral232). On that occasion, since the strength (Pii) of the compression spring constituting the elastic member224is set to be equivalent to the force that is required to move the valve rod21, the rod conjunction member221, the first fixing member222, and the second fixing member223, the spring224is substantially not contracted (thus, the bottom surface of the rod conjunction member221is kept in contact with the inner bottom surface of the inner frame218during the first lowering operation).

With lowering of the rod conjunction member221, the valve rod21also lowers (as denoted by numeral233), and the lower end of the valve rod21comes into contact with the valve seat6. Accordingly, the communication between the discharge flow path4and the storage container2is cut off, whereby the liquid material is stopped from flowing out from the discharge port.

A lowering operation of bringing the position of the valve rod21into a safely closed position is now described with reference toFIG. 13. When the actuator rod31continues to extend downward after the lower end of the valve rod21has come into contact with the valve seat6, the slider216further lowers (as denoted by numeral234), and the inner frame218fixed to the slider216also lowers together (as denoted by numeral235). With lowering of the inner frame218, the detection plate45attached to the inner frame218departs away from the sensor43. Upon detecting such a state, the sensor43sends a detection signal to the discharge control device33. The discharge control device33stores, as the initial detected position (or the contact position), a position where the detection plate45departs away from the sensor43.

When the slider216lowers in the state that the lower end of the valve rod21is in contact with the valve seat6as described above, the elastic member224is contracted and generates repulsive force acting to bias the rod conjunction member221downward (as denoted by numeral236). The biasing force acts to press the valve rod21against the valve seat6(as denoted by numeral237), thereby, as in the first embodiment, bringing the actuator rod31into the safely closed position where it is further lowered from the initial detected position by a predetermined distance (e.g., 1 mm). As a result, closing of the valve seat6by the valve rod21is ensured.

The discharge operation is similar to that in the first embodiment, and hence description of the discharge operation is omitted. The discharge device1according to the third embodiment is also mounted to the application device101and used in a negative pressure environment as in the first embodiment.

The above-described discharge device1according to the third embodiment can also suppress, as in the first embodiment, a drop of liquid pressure caused near the lower end of the valve rod21and generation of bubbles due to the drop of liquid pressure.

Fourth Embodiment

A liquid material discharge device1according to a fourth embodiment, illustrated inFIG. 14, is similar to the third embodiment in that the discharge device includes the outer frame201, the inner frame218, the sensor43, and the detection plate45attached to the inner frame, and that the sensor43detects valve closing in accordance with vertical movement of the inner frame, but it is mainly different from the third embodiment in including the extension member60similar to that in the second embodiment. In the following, elements common to the third embodiment are denoted by the same reference numerals, and description of those elements is omitted in some cases.

As in the third embodiment, the fourth embodiment includes the valve rod21having a length extending to a position near the actuator28, the first bushing208, the second bushing209, the rod conjunction member221, the first fixing member222, the second fixing member223, and the elastic member224through all of which the valve rod21is inserted. With guide of the first bushing208and the second bushing209, straight-moving stability of the valve rod21is improved, and the contact position between the lower end of the valve rod21and the valve seat6is prevented from displacing.

The fourth embodiment further includes, as in the second embodiment, the extension member60for fluid communication between the syringe2and liquid chamber59. According to the fourth embodiment, since the valve rod21is not inserted into the syringe2, the length of the valve rod21can be shortened, and wobbling of the lower end of the valve rod21can be reduced.

Other components are the same as those in the second embodiment or the third embodiment, and hence description of those components is omitted.

The discharge operation is similar to that in the third embodiment, and hence description of the discharge operation is omitted. The discharge device1according to the fourth embodiment is also mounted to the application device101and used in a negative pressure environment as in the first to third embodiments.

The above-described discharge device1according to the fourth embodiment can also suppress the generation of bubbles by controlling the rising speed and the acceleration of the valve rod21as in the first to third embodiments.

Moreover, since the existing syringe2is connected using the extension member60, maintenance work is easy to carry out.

Fifth Embodiment

The fifth embodiment relates to a discharge device1including a rod support mechanism238for supporting the small-diameter portion of the valve rod.

FIG. 15is a partial sectional view of the discharge device according to the fifth embodiment. InFIG. 15, (a) is a front view, and (b) is a sectional view taken along a line D-D in (a) when viewed in a direction denoted by arrow.FIG. 15(a)illustrates the lower end and thereabout of the valve rod in an enlarged scale.

As illustrated inFIG. 15(a), the discharge device1according to the fifth embodiment includes the rod support mechanism238that is formed inside the inner tube8of the syringe2over an entire length of the inner tube8. The rod support mechanism238includes four rod-support slide portions239and four communication grooves240.

As illustrated inFIG. 15(b), the four rod-support slide portions239and the four communication grooves240are arranged in the form of a ring at equal intervals. Respective inner peripheral surfaces of the rod-support slide portions239and the communication grooves240define an inner peripheral surface of the inner tube8.

As in the first to fourth embodiments, the valve rod21is a step-formed rod having a smaller diameter near its lower end. The four rod-support slide portions239function as guide members for improving the straight-moving stability of the valve rod21by supporting the small-diameter portion of the valve rod21while slidably contacting an outer peripheral surface thereof. The communication grooves240for communicating the large-diameter portion of the syringe2and the communication hole7in the valve seat6with each other are each disposed between adjacent two of the rod-support slide portions239. The liquid material stored in the large-diameter portion of the syringe2is supplied to the communication hole7through the four communication grooves240.

While the four rod-support slide portions239and the four communication grooves240are provided in this embodiment, the numbers of those components are not limited to four, and they may be 2, 3, or 5 or more. When the plural rod-support slide portions239and the plural communication grooves240are arranged, they are preferably arranged at equal intervals.

While, in this embodiment, the rod support mechanism238is formed integrally with the inner tube8of the syringe2, the rod support mechanism238may be constituted by a separate part and may be attached to the existing syringe2later.

According to this embodiment, since the rod support mechanism238is disposed near the lower end of the valve rod21(i.e., near the contact position between the valve rod21and the valve seat6), it is possible to reduce the wobbling of the lower end of the valve rod21, and hence to reduce the displacement of the contact position between the valve rod21and the valve seat6. As a result, the communication hole7in the valve seat6can be reliably closed by the lower end of the valve rod21.

The rod support mechanism238in this embodiment can be applied to any of the above-described first to fourth embodiments. In particular, when the rod support mechanism238is applied to the third or fourth embodiment, the straight-moving stability of the valve rod21can be significantly improved because the valve rod21is guided at three points by the first bushing208, the second bushing209, and the rod support mechanism238, which are arranged in spaced relation along the length direction of the valve rod21.

Sixth Embodiment

The sixth embodiment relates to a discharge device1including a rod support mechanism238for supporting the large-diameter portion of the valve rod.

FIG. 16is a partial sectional view of the discharge device according to the sixth embodiment. InFIG. 16, (a) is a front view, and (b) is a sectional view taken along a line E-E in (a) when viewed in a direction denoted by arrow.FIG. 16(a)illustrates the lower end and thereabout of the valve rod in an enlarged scale.

In the discharge device1according to the sixth embodiment, the rod support mechanism238for supporting the valve rod21is disposed in the large-diameter portion of the syringe2above the inner tube8. The rod support mechanism238includes a third bushing241, a partition member242having a third bushing insertion hole243and liquid communication holes244, and a third bushing retainer235.

The third bushing241is a tubular member for supporting the valve rod21while slidably contacting its outer peripheral surface, and it functions as a guide member to prevent wobbling of the valve rod21.

The partition member242is a plate-like member having the third bushing insertion hole243formed at a center, and eight liquid communication holes244arranged at equal intervals around the third bushing insertion hole243.

The third bushing241is fitted to the third bushing insertion hole243and is fixedly held by the third bushing retainer235. The large-diameter portion of the syringe2is partitioned into an upper space and a lower space by the partition member242, but the liquid material is supplied from the upper space to the lower space through the liquid communication holes244.

A diameter size of each of the liquid communication holes244is set to such a value as enabling the liquid material to be sufficiently supplied while allowing the partition member242to maintain the strength enough to support the valve rod21. The number of the liquid communication holes244is not limited to eight, and it may be set to a desired number (preferably plural). When the plural liquid communication holes244are provided, they are preferably arranged at equal intervals about the center of the syringe2.

While, in this embodiment, the rod support mechanism238is formed integrally with the large-diameter portion of the syringe2, the rod support mechanism238may be constituted by a separate part and may be attached to the existing syringe2later.

According to this embodiment, since the rod support mechanism238is disposed in the large-diameter portion of the valve rod21, it is possible to reduce the wobbling of the lower end of the valve rod21, and hence to reduce the displacement of the contact position between the valve rod21and the valve seat6.

The rod support mechanism238in this embodiment can be applied to any of the above-described first to fourth embodiments. In particular, when the rod support mechanism238is applied to the third or fourth embodiment, the straight-moving stability of the valve rod21can be significantly improved because the valve rod21is guided by the three bushings that are arranged in spaced relation along the length direction of the valve rod21.

LIST OF REFERENCE SIGNS

1: discharge device,2: storage container/syringe,3: nozzle,4: discharge flow path,5; nozzle attachment member,6: valve seat,7: communication hole,8: inner tube (rod-tip insertion hole),9: flange,10: body lower member,11: flange support member,12: insertion portion,13: through-hole,14: projected portion,15: sealing member A,16: sealing member B,17: seal retainer,18: compressed-gas flow path,19: gas supply joint,20: compressed-gas supply pipe,21: valve rod,22: rod holder A,23: rod holder B,24: fastener,25: coupling member,26: drive transmission member,27: fixing member,28: actuator,29: actuator attachment plate,30: actuator support plate,31: actuator rod,32: control wiring,33: discharge control device,34: position detection mechanism,36: slide rail,37: upper slide block (rod conjunction member),38: lower slide block,39: slide attachment plate,40: upper pin,41: lower pin,42: elastic member (spring),43: sensor,44: attachment plate,45: detection plate,47: head cover,48: rising of actuator rod,49: rising of lower slide block,50: rising of upper slide block,51: rising of valve rod,52: lowering of actuator rod,53: lowering of lower slide block,54: lowering of upper slide block,55: lowering of valve rod,56: lowering of actuator rod,57: lowering of lower slide block,58: extended portion,59: liquid chamber,60: extension member,61: liquid supply flow path,62: liquid supply port,63: liquid supply joint,64: sealing member C,65: sealing member D,101: application device,102: base,103: application target/workpiece,104: table,105: X driving device,106: Y driving device,107: Z driving device,108: X moving direction,109: Y moving direction,110: Z moving direction,111: drive control device,112: cover,201: outer frame,202: fitting hole,203: opening (lateral surface),204: extension portion,205: rear portion,206: opening (rear surface),207: projected portion,208: first bushing,209: second bushing,210: first bushing retainer,211: second bushing retainer,212: first bushing insertion hole,213: second bushing insertion hole,214: sealing member,215: actuator support member,216: slider,217: slide rail,218: inner frame,219: first through-hole,220: second through-hole,221: rod conjunction member,222: first fixing member,223: second fixing member,224: elastic member,225: central axis,226: rising of slider,227: rising of inner frame,228: rising of rod holder,229: rising of valve rod,230: lowering of slider,231: lowering of inner frame,232: lowering of rod holder,233: lowering of valve rod,234: lowering of slider,235: lowering of inner frame,236: force biasing rod holder downward,237: force pressing valve rod against valve seat,238: rod support mechanism,239: rod-support slide portion,240: communication groove,241: third bushing,242: partition member,243: third bushing insertion hole,244: liquid communication hole,245: third bushing retainer