JP6763197B2 - Liquid discharger and liquid discharge method - Google Patents

Description

The present invention relates to a liquid discharger and a liquid discharge method.

Conventionally, assembling an electronic device or the like includes a step of applying a liquid such as an adhesive or a solder flux. Various devices for applying such a liquid have been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-25698

By the way, in recent years, electronic devices such as optical communication devices have been miniaturized and mounted at high density, and the parts handled in the component mounting and assembling processes have also been miniaturized and the component arrangement intervals have been narrowed. Along with this, for example, even in the application of UV (Ultra Violet) curable resin used for fixing parts, it is required to control the UV curable resin to a very small amount. Conventionally, a so-called dispenser for applying a liquid applies a liquid as a droplet at a desired position at the tip of a nozzle. Here, in order to reduce the diameter of the droplet in order to apply a minute amount, it is necessary to prepare a nozzle having an outer dimension smaller than the diameter of the droplet actually desired to be generated. However, a nozzle having a small external dimension is expensive and is disadvantageous in terms of cost. Patent Document 1 also does not correspond to the miniaturization of the droplet diameter.

On one side, the liquid ejector and liquid ejection method disclosed herein are subject to ejecting and coating small diameter droplets.

The liquid discharger disclosed in the present specification is a plate-shaped portion formed on an outer cylinder portion and a bottom portion of the outer cylinder portion and having a first surface and a second surface which is a back surface of the first surface. A liquid drop ejection portion provided with a droplet ejection port and an outer cylinder portion are arranged inside the outer cylinder portion, and the tip surface is provided so as to face the first surface, and the tip surface contacts the first surface. In this state, a supply pipe that supplies a liquid that forms the droplets to the discharge port from the tip opening formed in the tip surface, and a separation mechanism that separates the first surface and the tip surface. The liquid supplied to the discharge port through the tip opening is in a state of forming droplets at the discharge port, and the first surface of the droplet discharge portion and the tip surface of the supply pipe are in contact with each other. In the separated state, air is supplied only to the air introduction portion surrounded by the inner peripheral wall surface of the outer cylinder portion and the outer peripheral wall surface of the supply pipe, and the air is supplied between the first surface and the tip surface. A blower mechanism for feeding into the space formed in the water is provided, and the diameter of the discharge port is equal to or smaller than the inner peripheral diameter of the supply pipe.

The liquid discharge method disclosed in the present specification is a plate-shaped portion having a first surface and a second surface as the back surface of the first surface, the diameter of which is equal to or less than the inner peripheral diameter of the supply pipe, and the droplets are formed. discharge port and the first surface of the droplet discharge unit provided ejected, in a state in which said contacting a tip surface of the feed tube distal end opening in the distal end surface is formed, the supply pipe While continuing the step of supplying the liquid forming the droplets and the supply of the liquid to the supply pipe, the droplets of the liquid discharged from the discharge port grow to a predetermined droplet diameter. It includes a step of causing the droplet to grow to a predetermined diameter, and then a step of separating the first surface and the tip surface .

According to the liquid discharger and the liquid discharge method disclosed in the present specification, droplets having a small diameter can be discharged and applied.

FIG. 1 is an explanatory diagram schematically showing a schematic configuration of a liquid discharger according to an embodiment. FIG. 2A is an explanatory view showing a state in which the liquid drop ejection portion and the tip surface of the supply pipe are in contact with each other, and FIG. 2B is a diagram in which the liquid drop ejection portion and the tip surface of the supply pipe are separated. It is explanatory drawing which shows the state. FIG. 3 is a flowchart showing an example of control of the liquid discharger. 4 (A), 4 (B), and 4 (C) are explanatory views showing how droplets are dropped from the liquid ejector. FIG. 5 is an explanatory diagram schematically showing how air flows through the air passage. FIG. 6 is an explanatory diagram showing a liquid drop ejection unit and a supply pipe of another embodiment. FIG. 7 is an explanatory view showing a liquid drop ejection unit and a supply pipe according to still another embodiment. FIG. 8 is an explanatory diagram schematically showing a schematic configuration of a liquid discharger according to another embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be shown so as to completely match the actual ones. In addition, depending on the drawing, for convenience of explanation, components that actually exist may be omitted, or the dimensions may be exaggerated than they actually are.

(Embodiment)
First, a schematic configuration of the liquid discharger 1 of the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram schematically showing a schematic configuration of a liquid discharger according to an embodiment. FIG. 2A is an explanatory view showing a state in which the liquid drop ejection portion and the tip surface of the supply pipe are in contact with each other, and FIG. 2B is a diagram in which the liquid drop ejection portion and the tip surface of the supply pipe are separated. It is explanatory drawing which shows the state.

The liquid discharger 1 of the present embodiment discharges a liquid UV curable resin. The UV curable resin is used for fixing parts of optical communication equipment to a substrate or the like. The application of such a liquid discharger 1 is not limited to the coating of a UV curable resin, and can also be used for the coating of other liquids. The liquid discharger 1 includes an outer cylinder portion 2 and a supply pipe 3. The outer cylinder portion 2 is arranged around the supply pipe 3. A plate-shaped droplet ejection portion 2a is formed on the bottom of the outer cylinder portion 2. The droplet ejection portion 2a is provided with a ejection port 2a1. The inner peripheral wall surface 2a11 of the discharge port 2a1 is a hydrophilic surface. The liquid drop ejection portion 2a is a plate-shaped portion, and has a first surface 2a2 and a second surface 2a3 which is a back surface of the first surface 2a2. The first surface 2a2 is located inside the outer cylinder portion 2, and the second surface 2a3 is located outside the outer cylinder portion 2. The first surface 2a2 and the second surface 2a3 are water-repellent surfaces.

The inside of the supply pipe 3 serves as a resin supply path, and the UV curable resin 4 is circulated. A liquid storage unit 5 for storing the UV curable resin is provided above the supply pipe 3. The base end portion of the supply pipe 3 is connected to the lower portion of the liquid storage portion 5. The inner peripheral wall surface 3a of the supply pipe 3 is a hydrophilic surface. A tip opening 3c is formed in the tip surface 3b located at the tip of the supply pipe 3. The tip surface 3b of the supply pipe 3 faces the first surface 2a2 of the liquid drop ejection portion 2a, and is in contact with the first surface 2a2. The tip surface 3b is a water-repellent surface. The UV curable resin 4 supplied through the supply pipe 3 is supplied to the discharge port 2a1 from the tip opening 3c in a state where the tip surface 3b is in contact with the first surface 2a2 of the liquid drop ejection portion 2a.

Here, the hydrophilic surface and the water-repellent surface are organized. In the present embodiment, the first surface 2a2 and the second surface 2a3 of the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3 are water-repellent surfaces. For the water repellent treatment applied to these surfaces, a conventionally known method can be adopted. On the other hand, the inner peripheral wall surface 2a11 of the discharge port 2a1 and the inner peripheral wall surface 3a of the supply pipe 3 are hydrophilic surfaces. For the hydrophilic treatment applied to these surfaces, a conventionally known method can be adopted. In this way, the water-repellent surface and the hydrophilic surface are provided so that the UV curable resin is wetted with the first surface 2a2 and the second surface 2a3 of the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3. This is to suppress the spread and maintain a spherical minute droplet diameter. In addition, in order to make the explanation easy to understand, the water-repellent surface and the hydrophilic surface are shown by different hatching in FIG. 2 and the like.

The liquid discharger 1 includes an elevating part 6. The elevating portion 6 includes a holding portion 6a that can be elevated and lowered. The holding portion 6a holds the outer cylinder portion 2. As a result, the outer cylinder portion 2 and, by extension, the liquid drop ejection portion 2a can be raised and lowered. The elevating part 6 is an example of a separation mechanism. That is, by lowering the liquid drop ejection portion 2a, the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 can be separated.

The liquid discharger 1 includes an air introduction unit 7. In the present embodiment, the region surrounded by the inner peripheral wall surface of the outer cylinder portion 2 and the outer peripheral wall surface of the supply pipe 3 is the air introduction portion 7. When the droplet ejection portion 2a is in the lowered state, the gap formed between the first surface 2a2 of the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 is the air communicating with the air introduction portion 7. The passage 7a is formed.

The liquid discharger 1 includes a support column 9 erected on the base 8. An elevating portion 6 is attached to the support column 9. Further, a support portion 10 is attached to the support column 9. The support portion 10 supports the liquid storage portion 5. A supply pipe 3 is connected to the liquid storage unit 5. Therefore, the supply pipe 3 is fixed to the support column 9 via the support portion 10 and the liquid storage portion 5. On the other hand, the outer cylinder portion 2 is held by the elevating portion 6 and can be raised and lowered. As a result, the first surface 2a2 of the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3 can be brought into contact with each other or separated from each other. As for the separation mechanism, the separation mechanism for separating the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3 may be any one capable of changing the relative positions of both. That is, in the present embodiment, the liquid drop ejection unit 2a is raised and lowered, but the supply pipe 3 may be raised and lowered, or both may be raised and lowered.

The liquid discharger 1 includes a grip portion 11 that grips the object to be coated 12. The grip portion 11 is attached to the support column 9, and the object to be coated 12 can be moved in the three-dimensional direction, that is, in the XYZ direction.

The liquid discharger 1 includes a first imaging camera 13 and a second imaging camera 14. The first imaging camera 13 photographs the droplet 4a ejected from the ejection port 2a1 of the droplet ejection portion 2a. The droplet diameter is determined from the captured image. The second imaging camera 14 is used for positioning the object to be coated 12.

The liquid discharger 1 includes an air supply unit 15. The air supply unit 15 includes a compressed air source. A first air supply path 15a and a second air supply path 15b are connected to the air supply section 15, and it is possible to control how much air is supplied to which air supply path. The air supply unit 15 is connected to the liquid storage unit 5 through the first air supply path 15a. When the UV curable resin 4 is discharged, the air supply unit 15 supplies compressed air into the liquid storage unit 5 and pressurizes the inside of the liquid storage unit 5. As a result, the UV curable resin 4 in the liquid storage portion 5 is pushed out into the supply pipe 3. Further, the air supply unit 15 is connected to the air introduction unit 7 through the second air supply path 15b. When air is introduced into the air introduction portion 7 when the droplet discharge portion 2a is lowered and an air passage 7a is formed between the droplet discharge portion 2a and the tip surface 3b of the supply pipe 3. An air flow is generated in the air passage 7a. This air flow destroys the surface tension of the droplet 4a of the UV curable resin 4 and acts to separate the droplet 4a. The separated droplet 4a falls and is transferred to the object to be coated 12. The air supply unit 15 and the second air supply path 15b are an example of a ventilation mechanism that sends air between the supply pipe 3 and the liquid drop discharge unit 2a.

The liquid discharger 1 includes a control unit 16. The control unit 16 is electrically connected to the elevating unit 6, the grip unit 11, the first imaging camera 13, the second imaging camera 14, and the air supply unit 15. Hereinafter, an example of the application work of the UV curable resin 4 by the liquid discharger 1 will be described with reference to FIGS. 3 to 5. FIG. 3 is a flowchart showing an example of control of the liquid discharger. 4 (A), 4 (B), and 4 (C) are explanatory views showing how droplets are dropped from the liquid ejector. FIG. 5 is an explanatory diagram schematically showing how air flows through the air passage.

First, in step S1, the liquid drop ejection unit 2a is moved to a predetermined initial position. In the present embodiment, the outer cylinder portion 2 is raised by the holding portion 6a, and the first surface 2a2 of the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 are brought into contact with each other.

In step S2, which is performed following step S1, coating alignment is performed. That is, the grip portion 11 is operated so that the coating object 12 comes to a predetermined position while checking the image captured by the second imaging camera 14. The order of the step S1 and the step S2 may be changed, or the steps may be performed at the same time.

In step S3, which is performed following step S1 and step S2, the inside of the liquid storage unit 5 is pressurized. The degree of pressurization is set according to the viscosity of the UV curable resin 4 to be coated, the coating amount, and the like. As a result, as shown in FIG. 4A, the UV curable resin 4 starts to be discharged from the discharge port 2a1, and the growth of the liquid droplet 4a is started. The state of growth of the droplet 4a is photographed by the first imaging camera 13.

In the droplet 4a, the first surface 2a2, the second surface 2a3 of the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 are water-repellent surfaces, and the inner peripheral wall surface 2a11 of the ejection port 2a1 and the inner circumference of the supply pipe 3 Since the wall surface 3a is a hydrophilic surface, it grows spherically without getting wet and spreading.

In step S4, which is performed following step S3, it is determined whether or not the droplet 4a has grown to a preset size. If YES is determined in step S4, the process proceeds to step S5. On the other hand, when NO is determined in step S4, the steps from step S3 are repeated, and the process is continued until YES is determined in step S4.

In step S5, as shown in FIG. 4B, the liquid drop ejection portion 2a is lowered. As a result, the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3 are separated. As a result, an air passage 7a is formed between the liquid drop ejection portion 2a and the tip surface 3b of the supply pipe 3.

In step S6, which is performed following step S5, it is determined again whether or not the droplet 4a has grown to a preset size. This determination is also determined based on the image captured by the first imaging camera 13. If YES is determined in step S6, the process proceeds to step S7. On the other hand, when NO is determined in step S6, the steps from step S1 are repeated. The reason why the droplet diameter is confirmed again in step S6 is that the droplet diameter of the UV curable resin 4 is within a desired range in consideration of the fact that the droplet 4a is dropped and applied in the subsequent step. This is to determine whether or not the size is such that it can be applied. Therefore, the droplet diameter that serves as the determination criterion in step S6 is the final diameter of the droplet 4a immediately before it falls. On the other hand, the droplet diameter, which is the determination standard in step S4, is determined in consideration of the change that occurs in the droplet 4a by going through the steps after step S4. That is, considering that the supply of the UV curable resin 4 is continued through the supply pipe 3 even after step S4 and that the liquid drop ejection portion 2a is descending, the droplet diameter serving as the determination standard in step S4 is taken into consideration. Has been decided.

In step S7, air is introduced into the air introduction unit 7. Referring to FIG. 5, the air introduced into the air introduction unit 7 goes toward the air passage 7a and passes through the air passage 7a as shown by the arrow 18a. By forming such an air flow, the surface tension of the UV curable resin 4 can be destroyed to separate the droplets 4a, which can be dropped onto the object to be coated 12 and transferred. As shown by arrow 18d, the air introduced into the air introduction unit 7 exerts an action of pushing out the liquid droplet 4a, so that the liquid droplet 4a can be appropriately dropped. In the present embodiment, the air passing through the air passage 7a as shown by the arrow 18b rises as shown by the arrow 18c, but instead of such an air flow, it is lowered at any position. The flow of air may be directed.

In step S8, which is performed following step S7, it is confirmed that the droplet 4a has been dropped as shown in FIG. 4C, and a series of steps is completed (END).

Here, the formation and dropping of droplets at the tip of a general nozzle will be described. The UV curable resin that has passed through the inside of the nozzle and reached the tip of the nozzle wets and spreads at the tip of the nozzle to increase the droplet diameter. The droplets fall when the diameter of the droplets increases and their own weight destroys the surface tension acting on the contact surface with the nozzle. The diameter of the droplet at the time of falling is much larger than the outer diameter of the nozzle.

On the other hand, in the present embodiment, the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 are separated, and an air passage formed between the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 is formed. Let air pass through 7a. It is considered that the operation itself of separating the droplet ejection portion 2a and the tip surface 3b of the supply pipe 3 also contributes to weakening the surface tension of the droplet 4a, and further, by allowing air to pass through, the droplet 4a Can destroy the surface tension of. As a result, the liquid drop 4a can be dropped even if the liquid drop 4a does not grow large. That is, a minute amount of the UV curable resin 4 can be applied.

According to the liquid ejector 1 of the present embodiment, droplets having a small diameter can be ejected and applied. Therefore, the UV curable resin 4 can be applied to a minute coating area of the component or a narrow area that the nozzle cannot reach.

(Modification example)
Next, various modification examples will be described. First, with reference to FIG. 6, a liquid drop ejection portion 2a in which the diameter R2 of the discharge port 2a1 is smaller than the inner peripheral diameter R1 of the supply pipe 23 will be described. The supply pipe 23 has a larger diameter than the supply pipe 3. The supply pipe 23 having a large diameter is advantageous in terms of manufacturing cost. Further, as compared with the production of a supply pipe having a small diameter, it is easier to process the plate-shaped droplet ejection portion 2a by providing a minute ejection port 2a1. If the diameter R2 of the discharge port 2a1 is made smaller than the inner peripheral diameter R1 of the supply pipe 23, the diameter of the discharged droplets can be reduced.

Next, with reference to FIG. 7, an example in which the thickness around the discharge port 22a1 of the liquid drop discharge portion 22a is reduced toward the discharge port 22a1 will be described.
The second surface 22a3 of the liquid drop ejection portion 22a formed on the bottom of the outer cylinder portion 22 is a tapered surface. As a result, the depth d of the discharge port 22a1 can be made shallow. By making the depth d of the discharge port 22a1 shallow, it is possible to make it easier for the droplet 4a to fall. That is, the droplet 4a can be dropped even when the droplet diameter is small, and a minute amount of the UV curable resin 4 can be easily applied. Further, referring to FIG. 7, the introduction side edge portion 22a12 facing the supply pipe 23 of the discharge port 22a1 is in a chamfered state. By chamfering the introduction side edge portion 22a12, the UV curable resin 4 can be easily introduced. In the present embodiment, the chamfering process has an R shape, but other shapes may be used.

Further, referring to FIG. 8, the second air supply path 15b is abolished. If the droplet 4a can be dropped without introducing air due to conditions such as the viscosity of the UV curable resin, the second air supply path 15b may be abolished. In this case, the weight of the liquid drop 4a and the liquid drop ejection portion 2a are lowered, and the liquid drop 4a is dropped by the operation of separating from the tip surface 3b of the supply pipe 3.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

1 Liquid discharger 2, 22 Outer cylinder 2a, 22a Droplet discharge 2a1, 22a1 Discharge port 2a11 Inner peripheral wall surface 2a2 First surface 2a3, 22a3 Second surface 3 Supply pipe 3a Inner peripheral wall surface 3b Tip surface 3c Tip opening 4 UV curable resin 4a Droplet 5 Liquid storage part 6 Elevating part 7 Air introduction part 7a Air passage 12 Application object 13 1st imaging camera 14 2nd imaging camera 15 Air supply unit 15a 1st air supply path 15b 2nd air supply path 16 Control unit

Claims (8)

Outer cylinder and
A plate-shaped portion formed at the bottom of the outer cylinder portion and having a first surface and a second surface which is a back surface of the first surface, and a droplet ejection portion provided with a droplet ejection port. ,
From the tip opening formed in the tip surface in a state where the tip surface is provided inside the outer cylinder portion and the tip surface faces the first surface and the tip surface is in contact with the first surface. A supply pipe that supplies the liquid that forms the droplets to the discharge port,
A separation mechanism that separates the first surface and the tip surface,
The liquid supplied to the discharge port through the tip opening is in a state of forming droplets at the discharge port, and the first surface of the droplet discharge portion and the tip surface of the supply pipe are separated. In this state, air is supplied only to the air introduction portion surrounded by the inner peripheral wall surface of the outer cylinder portion and the outer peripheral wall surface of the supply pipe, and the air is supplied between the first surface and the tip surface. A ventilation mechanism that sends air into the formed space ,
With
A liquid discharger having a diameter of the discharge port equal to or smaller than the inner circumference of the supply pipe. The liquid discharger according to claim 1, wherein the diameter of the discharge port is smaller than the inner circumference of the supply pipe. The liquid discharger according to claim 1 or 2, wherein the plate thickness of the droplet discharge portion around the discharge port is reduced toward the discharge port. The liquid discharger according to any one of claims 1 to 3, wherein the introduction side edge portion of the discharge port facing the supply pipe is chamfered. The liquid discharger according to any one of claims 1 to 4, wherein the droplet discharge portion is formed at the bottom of an outer cylinder portion arranged around the supply pipe. The liquid is a UV curable resin
The liquid discharger according to any one of claims 1 to 5, wherein at least one of the first surface, the second surface, and the tip surface of the supply pipe is a water-repellent surface. The liquid is a UV curable resin
The liquid discharger according to any one of claims 1 to 6, wherein at least one of the inner peripheral surface of the discharge port and the inner peripheral surface of the supply pipe is a hydrophilic surface. It is a plate-shaped portion having a first surface and a second surface which is the back surface of the first surface, has a diameter equal to or less than the inner circumference of the supply pipe, and is provided with a discharge port for discharging droplets. A liquid forming the droplet is supplied to the supply pipe in a state where the first surface of the droplet ejection portion and the tip surface of the supply pipe having a tip opening formed in the tip surface are in contact with each other. And the process to do
A step of growing droplets of the liquid discharged from the discharge port to a predetermined droplet diameter while continuing to supply the liquid to the supply pipe.
A step of separating the first surface and the tip surface after the droplet has grown to a predetermined diameter,
Liquid discharge method including.

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