JPS6340146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive spraying device, and is particularly suitable for spraying starch glue, synthetic glue, etc. in labeling machines, packaging machines, etc.
The present invention relates to an adhesive spraying device that can spray adhesives such as synthetic polymer adhesives and heat-melting adhesives onto objects to be sprayed such as labels, packaging containers, and wrapping paper.

FIG. 1 is an explanatory diagram showing an adhesive application method used in a conventional labeling machine. In this adhesive application method, a label 3 is adsorbed to a label adsorption portion 2 of a vacuum roll 1, and then glue can be applied to the label 3 with a glue roll 4. Here, the glue is stored in a glue pan 5, and the glue in the glue pan 5 can be transferred to the glue roll 4 via an intermediate glue roll 6. Here, the glue roll 4 and the intermediate glue roll 6 are constantly rotating. Note that 7 is a peeling plate that prevents the label 3 from sticking to the glue roll 4.

However, the adhesive application method shown in FIG. 1 has the following drawbacks. That is, (1) the gap W between the opening edge of the glue pan 5 and the circumferential surface of the intermediate glue roll 6;
It is difficult to adjust the thickness of the adhesive applied to the label 3 based on the adjustment. (2) The glue in the glue pan 5 flows while drawing in air under the influence of the rotation of the intermediate glue roll 6, and the viscosity of the glue tends to change during long-term use. (3)
When changing the type of glue due to a change in the object to be coated, or at the end of work, it is necessary to remove the glue roll 4, glue pan 5, intermediate glue roll 6, etc. from the device frame and wash them, which requires a large amount of cleaning. Requires effort. (Four)
In order to prevent glue from adhering to the label suction part 2, the area of the label suction part 2 needs to be slightly smaller than the area of the label 3, and each time the shape of the label 3 is changed, the label suction part 2 of the vacuum roll 1 It is necessary to replace it. (5) Since the label 3 is applied while the glue roll 4 is in contact with the label 3, there is a risk that the label 3 may be misaligned with respect to the label suction unit 2, as shown in FIG. 3 cannot be pasted with high precision.

FIG. 3 is an explanatory diagram showing an adhesive spraying method used in conventional packaging machines. In this adhesive spraying method, compressed air is jetted around the supply nozzle 9 connected to the glue tank 8 and the opening of the supply nozzle 9, and a negative It has a spray nozzle 10 that forms a pressure region V. That is, the glue located at the opening of the supply nozzle 9 is blown out by the negative pressure formed by the compressed air jetted from the spray nozzle 10 and then
The compressed air ejected from the air turns into a mist and is sprayed onto the object to be sprayed. Note that A indicates compressed air.

However, the adhesive spraying method according to FIG. 3 has the following drawbacks. In other words, (1) the glue is sucked out from the supply nozzle 9 by the spraying nozzle 1;
Because it is based on the negative pressure formed by the compressed air jetted out from the spray nozzle 10, it is strongly influenced by the inertia of the glue and the friction of the glue transport pipe from the glue tank 8 to the supply nozzle 9, and the compressed air flows from the spray nozzle 10. Even if the glue starts to spray, the spraying of the glue does not start immediately, and the high-speed response of the glue spraying timing is poor. (2) Even if the jetting of compressed air from the spraying nozzle 10 is stopped after the spraying of the glue is finished, the glue drips from the opening of the supply nozzle 9 due to the inertia of the glue. (3) The amount of glue sprayed is determined by the opening area of the supply nozzle 9 and the magnitude of the negative pressure formed in front of the opening of the supply nozzle 9. It is difficult to control the amount applied. (4) If the device is left unused for a long time, the glue will harden at the opening of the supply nozzle 9 and will require cleaning before reuse. (5) The glue is sucked out from the supply nozzle 9 to the spray nozzle 10.
Because it relies on the negative pressure formed by the compressed air jetted out, it is only possible to spray relatively low-viscosity glue, and it is not possible to smoothly spray relatively high-viscosity glue. (6) It is very difficult to clean the supply nozzle 9 and the glue transport pipe when changing the type of glue due to changing the object to be sprayed or when finishing the work.

The present invention provides good controllability of the adhesive spraying timing, spraying range, and spraying amount, provides good initial adhesion, suppresses viscosity changes and hardening of the adhesive,
It is an object of the present invention to provide an adhesive spraying device that can smoothly spray even a relatively high viscosity adhesive and can be easily cleaned.

In order to achieve the above object, an adhesive spraying device according to the present invention includes a supply nozzle capable of discharging adhesive in an adhesive container, and a supply nozzle that is disposed opposite to the supply nozzle with a predetermined gap therebetween. a return nozzle that sucks in the adhesive discharged from the supply nozzle and can return it to the adhesive container; and a spray nozzle that allows compressed air to act on the adhesive and spray the adhesive onto the object to be sprayed.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a piping system diagram showing an adhesive spraying device according to an embodiment of the present invention. Adhesives such as starch glue, synthetic glue, and solvent-based glue can be stored in the semi-sealed adhesive container 11 provided with air holes. This adhesive container 11 has a supply pipe 12
is inserted. A suction port of a supply pump 16 is connected to the supply pulp 12 via a conduit 13, a switching valve 14, and a conduit 15. A supply nozzle 18 is connected to the discharge port of the supply pump 16 via a conduit 17 . That is, under the operation of the supply pump 16, the supply nozzle 18
The adhesive in the adhesive container 11 can be discharged from its discharge port 18A. Here, supply pump 1
6 is a discharge flow rate that matches the required spraying amount of the adhesive and enables the adhesive to be discharged.

Further, the suction port 19A of the return nozzle 19 is arranged to face the discharge port 18A of the supply nozzle 18 with a predetermined gap G interposed therebetween. A return pump 2 is connected to the return nozzle 19 via a conduit 20.
1 suction port is connected. Return pump 2
1, a pipe line 22, a switching valve 23, a pipe line 2
4, a return pipe 25 inserted into the adhesive container 11 is connected. That is, the return nozzle 19 can suck the adhesive discharged from the discharge port 18A of the supply nozzle 18 from its suction port 19A under the operation of the return pump 21 and return it to the adhesive container 11. Here, the return pump 21 can simply suck in the adhesive at a suction flow rate that makes it possible to return the adhesive. Moreover, the opening 25A in the container 11 of the return pipe 25
A constant gap is always maintained between the upper surface of the adhesive stored in the container 11 and the upper surface of the adhesive stored in the container 11 so that the air discharged into the container 11 from the opening 25A does not infiltrate into the adhesive stored in the container 11. It is possible to form.

Further, a jet port 26A of the compressed air blowing nozzle 26 is arranged at a position facing the gap G formed by the discharge port 18A of the supply nozzle 18 and the suction port 19A of the return nozzle 19. The spray nozzle 26 has a conduit 27 equipped with an on-off valve 27A.
A compressor 28 is connected via. That is, under the operation of the compressor 28, the spray nozzle 26 can apply compressed air to the adhesive discharged from the discharge port 18A of the supply nozzle 18, and can spray the adhesive onto the object to be sprayed. It is said that

In FIG. 4, 29 is a cleaning liquid container, the supply pipe 30 of the cleaning liquid container 29 is connected to the switching valve 14 via a conduit 31, and the return pipe 32 is connected to the switching valve 14 via a conduit 33. and is connected to the switching valve 23. As the cleaning liquid stored in the cleaning liquid container 29, water is used when the adhesive stored in the adhesive container 11 is starch glue or synthetic glue; A solvent is used when the adhesive is a solvent-based adhesive.

Next, the operation of the above embodiment will be explained.

During non-spraying when compressed air is not ejected from the spray nozzle 26, the adhesive container is After the adhesive in the supply nozzle 11 is discharged from the discharge port 18A of the supply nozzle 18 under the operation of the supply pump 16, as shown in FIG.
9 into the suction port 19A and returned to the adhesive container 11. In other words, during this non-spraying,
The adhesive in the adhesive container 11 is
The air is circulated through a circulation system consisting of the supply pump 16, the supply nozzle 18, the return nozzle 19, and the return pump 21, and in the small gap G between the supply nozzle 18 and the return nozzle 19, air is slightly Since it is only touched, it maintains its viscosity for a long time, and the discharge port 18A of the supply nozzle 18 and the suction port 19A of the return nozzle 19.
The above circulating state is maintained without curing.

Here, from the supply nozzle 18 to the return nozzle 1
In order to ensure the transfer of the adhesive to the supply nozzle 18, the suction capacity of the return nozzle 19 must be
(1) Return nozzle 1
The inner diameter of the supply nozzle 9 is larger than the inner diameter of the supply nozzle 18,
and/or (2) the suction flow rate of the return pump 21 may be greater than the discharge flow rate of the supply pump 16.

When compressed air is ejected from the spray nozzle 26 under the above-mentioned circulation condition, as shown in FIG. At the bottom, it becomes fine particles, that is, a mist, and is sprayed onto the object to be sprayed.
Here, each supply nozzle 18, return nozzle 19
In order to prevent the adhesive from adhering to the spray nozzle 26, as shown in FIG. In order to do so, (1) each nozzle 1 with respect to the central axis of the spray nozzle 26;
Set the angle θ between the central axes of 8 and 19 from 0 to 180.
(2) With respect to the center of the discharge port 18A and suction port 19A of each nozzle 18, 19, the ejection port 26A of the spray nozzle 26 can be adjusted within a range of You can adjust the distance L installed on either side, (3) each nozzle 18,
The cross section perpendicular to the axis of the spray nozzle 26 may be adjusted to a shape that forms a laminar flow, such as a circular cross section, a rhombic cross section as shown in FIG. 7A, or an elliptical cross section as shown in FIG. 7B. (5) Adjust the cross section perpendicular to the axis to a circular cross section, elliptical cross section, rectangular cross section, etc., or (5)
It is necessary to adjust the cut angle α of the opening end face forming the discharge port 18A and suction port 19A of each nozzle 18, 19 with respect to the central axis of the spray nozzle 26.

After spraying the adhesive, when the jetting of compressed air from the spraying nozzle 26 is stopped, the adhesive discharged from the discharge port 18A of the supplying nozzle 18 is returned again as shown in FIG. 5A. The adhesive is sucked into the suction port 19A of the nozzle 19 and returned to the adhesive container 11, forming a circulating state in the circulation system. Note that the size of the gap G formed between the discharge port 18A of the supply nozzle 18 and the suction port 19A of the return nozzle 19 is such that all the adhesive discharged from the discharge port 18A remains when the adhesive is not sprayed. The size must be large enough to allow the adhesive to be transferred to the suction port 19A without any problems, and the size must be large enough to prevent the adhesive discharged from the discharge port 18A from adhering to the suction port 19A when spraying the adhesive.

When changing the type of adhesive due to a change in the object to be sprayed,
Alternatively, at the end of the spraying operation, the spraying device is cleaned in the following manner. That is, by switching the switching valves 14 and 23, the pipe line 15 and the pipe line 31, and the pipe line 22 and the pipe line 33 are connected, respectively, and the cleaning liquid stored in the cleaning liquid container 29 is transferred to the supply pump 16. And under the operation of the return pump 21, the cleaning liquid container 29, the supply pump 16, the supply nozzle 18, the return nozzle 1
9. The supply nozzle 18 and its piping system as well as the return nozzle 19 and its piping system are reliably and easily cleaned by being circulated through a circulation system consisting of the return pump 21.

In addition, the said Example illustrated and demonstrated the state which arrange|positioned each center axis of the supply nozzle 18 and the return nozzle 19, and the center axis of the spray nozzle 26 in the same plane. However, in the present invention, it is sufficient that the supply nozzle and the return nozzle are substantially opposed to each other with a predetermined gap in between, and the spray nozzle is faced to the gap. The central axes of the supply nozzle 18 and the return nozzle 19 may be arranged at arbitrary positions relative to each other, for example, as shown in FIG. The nozzle 26 may be arranged in a plane perpendicular to the central axis of the nozzle 26.

According to the adhesive spraying device according to the above embodiment,
It is possible to obtain the following effects. That is,
(1) When the adhesive is not being sprayed, the adhesive is constantly circulating and ready for spraying, and the adhesive is sprayed using compressed air, a fluid that has almost no inertia and is extremely easy to control. In addition, it becomes possible to reliably control the start timing and stop timing of adhesive spraying with good high-speed response. Therefore, the adhesive can be sprayed with high accuracy to a predetermined spraying necessary range on the object to be sprayed. (2) Supply pump 16
By adjusting the discharge amount, it is possible to reliably and easily control the amount of adhesive sprayed. Therefore, it is also possible to make the thickness of the adhesive formed on the object to be sprayed extremely thin, and it is possible to improve the initial adhesive strength of the adhesive. (3) Adhesives are sprayed with positive pressure of compressed air and become fine particles, so they have a large contact area with air and can dry quickly, which is a drawback when using starch glue or synthetic glue. It is possible to achieve a good initial adhesion force. (4) During non-spraying, the adhesive remains in contact with the outside air for a long time at positions other than the gap G between the discharge port 18A of the supply nozzle 18 and the suction port 19A of the return nozzle 19. It becomes possible to maintain a constant viscosity over time. Furthermore, even when using an adhesive that contains a solvent that is likely to sparkle, such as a solvent-based adhesive or a hot-melt adhesive, the adhesive is not exposed to the outside air at positions other than the gap G, and the solvent The initial performance of the adhesive can be maintained for a long time. In addition, when the adhesive is not sprayed, the discharge ports 18A of each nozzle 18, 19,
The adhesive does not harden at the suction port 19A, and spraying can be started quickly and smoothly even when reused after a long period of suspension. (5) The adhesive is forcibly discharged from the discharge port 18A of the supply nozzle 18 by the supply pump 16, and is blown away in the form of fine particles by the positive pressure of compressed air. , it becomes possible to spray even relatively high-viscosity adhesives smoothly. (6) Supply nozzle 1
8 and the return nozzle 19, as well as their piping systems, can be cleaned very easily and reliably by circulating the cleaning liquid in these piping systems under the operation of the supply pump 16 and the return pump 21. It becomes possible to do so. (7) When this adhesive spraying device is used in a label pasting machine, since each nozzle is not in contact with the label, the label will not be misaligned.

FIGS. 10 and 11 are layout diagrams showing an application example in which the adhesive spraying device according to the above embodiment is applied to a labeling machine. The label 42 can be adsorbed on the vacuum roll 41, and a plurality of spraying devices each consisting of a supply nozzle 18, a return nozzle 19, and a spraying nozzle 26 are used to attach the label 42 to the vacuum roll 41.
2 through a predetermined gap in the direction perpendicular to the feeding direction of label 42.
42D, and are arranged facing each other. Each spray device includes a phototube 43, a timer 44, a solenoid 45, and a switching valve 46. A timer 44 turns on the solenoid 45 after a predetermined time after the phototube 43 of each spraying device detects the passing of the tip of the label 42 in the corresponding spraying area.
By switching the switching valve 46, compressed air is blown out from the spraying nozzle 26, and the adhesive can be immediately sprayed onto the corresponding spraying area of the label 42. Also, after a predetermined time after each phototube 43 detects that the label 42 has passed the end of the corresponding spraying area,
The timer 44 turns off the solenoid 45 and stops spraying the adhesive onto the corresponding spray area.
That is, each spraying device arranged perpendicularly to the feeding direction of the label 42 has its own phototube 43, timer 44, and solenoid 4.
5. Since it is equipped with a switching valve 46, label 4
Regardless of the overall size and shape of the label 42, it is possible to spray the adhesive accurately only on the necessary spraying range of the label 42. In addition, when the shape of the label 42 is rectangular, it is possible to simultaneously control the start and stop of spraying from the spraying nozzles 26 of each spraying device using a single phototube, timer, and solenoid. Become.

That is, according to the above labeling machine, it is possible to arbitrarily apply adhesive to labels of any shape and size without any need to change the vacuum roll. In addition, since each nozzle 18, 19, 26 does not contact the label 42, there is no positional shift due to the application of adhesive on the label 42, and the label 42 is accurately placed at a predetermined affixing position on the object to be affixed. can be pasted, cleaning is very simple, and it is also possible to save time and effort required for setup and maintenance.

In addition, when the adhesive spraying device according to the present invention is used for spraying heat-melting glue used for attaching labels to synthetic resin containers, the glue supply system, return system, etc. heating all the parts passing through,
It is necessary to maintain the molten state of the glue.

As described above, the adhesive spraying device according to the present invention includes a supply nozzle capable of discharging adhesive in an adhesive container, and a supply nozzle that is disposed opposite to the supply nozzle with a predetermined gap therebetween. A return nozzle that sucks the adhesive discharged from the supply nozzle and returns it to the adhesive container; and a spray nozzle that can spray the adhesive onto the object to be sprayed. Therefore, according to the present invention, it is possible to control the spraying timing, spraying range, and spraying amount of the adhesive, and the initial adhesiveness is good, and the viscosity change and hardening of the adhesive are suppressed, and the adhesive is relatively Even high-viscosity adhesives can be sprayed smoothly, and cleaning can be performed easily.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the adhesive application method used in conventional labeling machines, Figure 2 is an enlarged view of main parts showing the application state of Figure 1, and Figure 3 is a conventional packaging machine. FIG. 4 is a piping system diagram showing an adhesive spraying device according to an embodiment of the present invention, and FIG. 5A is a non-spraying method in the same embodiment. Main part sectional view showing the condition, Figure 5B
6 is a sectional view of a main part showing the spraying state in the same embodiment, FIG. 6 is a perspective view showing the flow state of compressed air to the nozzle during spraying in the same embodiment, and FIG.
Figures A and B are sectional views showing different modifications of the nozzle in the same embodiment, Figure 8 is a side view showing the arrangement relationship of each nozzle in the same embodiment, and Figure 9 is a side view showing the arrangement relationship of each nozzle in the same embodiment.
The figure is a front view showing different arrangement relationships of each nozzle, FIG. 10 is a layout diagram showing an example of application of a labeling machine to which the present invention is applied, and FIG. 11 is a plan view of the main part of FIG. 10. . 11... Adhesive container, 18... Supply nozzle, 19
... Return nozzle, 26... Spraying nozzle, G... Gap.

Claims (1)

[Claims] 1 A supply nozzle capable of discharging the adhesive in the adhesive container, and a supply nozzle arranged opposite to the supply nozzle with a predetermined gap therebetween, and capable of sucking the adhesive discharged from the supply nozzle and returning it to the adhesive container. facing the gap formed by the return nozzle, the supply nozzle, and the return nozzle, apply compressed air to the adhesive discharged from the supply nozzle, and spray the adhesive onto the object to be sprayed. An adhesive spraying device comprising a spraying nozzle that enables spraying.