JP3081444B2 - Building plate coating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for coating a building board for coating a spot pattern having irregularly varying spot sizes on the surface of the building board.

[0002]

2. Description of the Related Art In recent years, as a technique for painting an irregular spot pattern on an uneven surface of a building board, Japanese Patent Application Laid-Open No. Hei 3-1863 has been disclosed.
As shown in Japanese Patent Publication No. 81, a coating method for coating with a spray gun has been proposed. This coating method discharges paint from a spray gun so as not to be atomized, and diffuses paint droplets in a scattered manner, thereby forming a spot pattern in which the size of spots changes irregularly on the surface of a building board. It is to be spray painted.

[0003]

By the way, the spray gun is essentially used by completely atomizing the paint (that is, by completely atomizing the paint, stable coating can be performed). As described above, if the paint is discharged from the spray gun without atomization, the spray paint is not diffused stably, and the size and density of spots tend to be uneven. In addition, since the diffusion area of the spray paint greatly expands in a circular or elliptical shape and the peripheral parts of the adjacent paint diffusion areas overlap, the density of the spots in the peripheral parts of the overlapping paint diffusion areas is increased, and the spot pattern is partially concentrated. Color or, conversely,
If the overlapping portion of the paint diffusion area is reduced, the density of the spots in the peripheral portion of the paint diffusion area is reduced, and in combination with the above-mentioned instability of the paint diffusion, the size and density of the spots are uniform. It is extremely difficult to paint a well-balanced, high quality spot pattern.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a high-quality spot pattern having a well-balanced extremely natural feeling without unevenness in spot size and density. An object of the present invention is to provide a method and an apparatus for painting a building board capable of painting on its surface.

[0005]

In order to achieve the above object, a method for coating a building board according to the present invention is arranged on a surface of a building board conveyed by conveying means so as to cover the entire width thereof. A method for coating a building board, in which a spot pattern is applied by spraying paint from a plurality of jet nozzles, wherein a height position of each jet nozzle is separated from the building board by 5 cm or more, and the jet nozzle is opened and closed. By repeating the opening and closing operation of the valve at a rate of 100 to 300 times / sec , the paint droplets ejected from each jet nozzle become irregular during the flight until reaching the surface of the building board. The droplets are divided into a plurality of droplets having different particle diameters, and a spot pattern whose spot size changes irregularly is painted on the surface of the building board (claim 1).

[0006] Good In this case, setting the previous SL arrangement pitch of each jet nozzle to 0.5 to 3.0 mm (claim
2 ).

[0007] The coating apparatus for performing the above-mentioned coating method comprises a conveying means for conveying a building board, and a coating means arranged at an interval of 0.5 to 3.0 mm in the width direction of the building board to be conveyed. What is necessary is just to have the structure provided with the several jet nozzle arrange | positioned 5 cm or more upwards, and the valve which opens and closes each of these jet nozzles at 100 to 300 times / second (Claim 3 ).

[0008]

The coating machine used in the present invention is not a conventional spray gun but an ink jet type coating apparatus using a jet nozzle. In the conventional ink jet coating, a jet nozzle is brought close to an object to be coated, and ink droplets ejected from the jet nozzle are concentrated on one point of the object to be formed to form one dot (one pixel). A pattern is drawn in an infinite number of sets along the pattern. Even with such conventional inkjet coating,
Using the coating method of Japanese Patent Application No. 4-330421, filed by the present applicant, makes it possible to paint a spot pattern by converting the spot pattern into pattern data, but it takes a lot of time and effort to create the pattern data. There is. After that, the present applicant has recently applied for a method of automatically generating the pattern data of the spotted pattern using a random number generation function of a computer. There is a disadvantage that it is complicated and its preparation is troublesome.

On the other hand, according to the present invention, the height position of the jet nozzle is separated from the building board by 5 cm or more, and the opening / closing operation of the valve for opening / closing the jet nozzle is controlled by 100 to 300.
By repeating at a rate of f / sec , a plurality of droplets having different particle sizes irregularly due to air resistance during the flight until the paint droplet ejected from the jet nozzle reaches the surface of the building board. And a spot pattern in which the size of the spot changes irregularly is painted. The concept of such a coating method is completely different from the conventional ink jet coating in which the number of dots per jet nozzle is “1”. By actively utilizing the cracks of the droplets, a spot pattern with a very natural feeling and a well-balanced pattern is painted without depending on the pattern data.

In this case, as shown in FIG. 3, the number of cracks of the paint droplets in flight and the particle size of the broken droplets change as shown in FIG. 3 depending on the opening / closing frequency of the valve for opening / closing each jet nozzle. Is set to 100 to 300 times / second, the number of cracks of the paint droplets in flight and the particle size of the broken droplets are suitable for the formation of a spot pattern.

Further, when the arrangement pitch of the jet nozzles arranged in the width direction of the building board is set to 0.5 to 3.0 mm, the paint jetted from each jet nozzle arranged at a height of 5 cm or more. The scattering areas of the droplets overlap moderately, and the density of speckles does not need to be reduced. In this case, the scattering area of the paint droplets ejected from each jet nozzle is extremely small as compared with the paint diffusion area of the spray gun. It is buried inside and is not at all noticeable.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. First, the configuration of the entire coating apparatus will be described with reference to FIGS. The building board 11, which is an object to be coated, is carried on a conveyor 12, which is carrying means. The conveyor 12 is driven to rotate by a driving roller 13. Further, in order to detect the presence or absence of the building board 11 passing through the position immediately before the start of the coating, a projector 14 and a light receiver 15 constituting a photoelectric tube sensor are arranged on both sides of the position of the conveyor 12 immediately before the start of the coating. Have been.

On the other hand, a coating head 16 is disposed above the coating position of the conveyor 12, and a number of jet nozzles 17 are attached to the lower surface of the coating head 16 downward via a valve 18. Each jet nozzle 17
Are arranged in a row in the width direction (that is, the direction orthogonal to the conveyance direction) so as to cover the entire width of the building board 11 to be conveyed, and the arrangement pitch is set to 0.5 to 3.0 mm. . Further, the height position of each jet nozzle 17 is set at a position 5 cm or more above the building board 11. The opening diameter of each jet nozzle 17 is, for example, 20
It is set to 0 to 300 μm.

The valve 18 of each of these jet nozzles 17
The valve control device 19 for controlling the opening and closing operation of the
5, it is determined whether or not the building board 11 has passed the position immediately before the start of painting, and immediately after the building board 11 has passed the position immediately before the start of painting, the opening / closing operation of each valve 18 is performed. Is started, a paint (ink) is ejected from each jet nozzle 17, and a spot pattern is painted on the uneven surface of the building board 11 which is conveyed to the painting position directly below the jet nozzle 17. At this time, the opening / closing frequency of each valve 18 is 10
It is set to 0 to 300 times / second. Since a large number of jet nozzles 17 are arranged in a line in the width direction of the building board 11 so that the coating range by each of the jet nozzles 17 covers the entire width of the building board 11, the jet nozzles 17
Is uniformly applied over the entire width of the surface of the building board 11 passing through the painting position immediately below.

The raw paint is stored in a closed paint tank 2.
It is stored in 0. In the paint tank 20, compressed air is supplied from a compressor 21 to a regulator 22.
The paint is supplied from the lower portion of the paint tank 20 to the paint head 16 while the pressure in the paint tank 20 is kept constant, and the paint is jetted from the jet nozzle 17 when the valve 18 is opened. I have.

According to the ink jet type coating apparatus configured as described above, the height position of the jet nozzle 17 is set at a position 5 cm or more above the building board 11.
For this reason, during the flight before the paint droplets ejected from the jet nozzle 17 reach the surface of the building board 11, FIG.
As shown in (2), the paint droplets are randomly divided into a plurality of droplets having different particle sizes due to air resistance. Thereby, as shown in FIG. 5, the spot pattern whose spot size changes irregularly is painted on the surface of the building board 11.

This ink jet type coating method does not spray the paint in an unstable state as in the above-mentioned coating method using the conventional spray gun, but paint droplets stably sprayed from the jet nozzle 17. Is divided into a plurality of droplets having different particle diameters by air resistance during flight, so that a spot pattern having a stable and uniform finish can be formed. This coating method has a completely different idea from the conventional ink jet coating in which the number of dots per jet nozzle is “1”, and paint droplets in flight which were regarded as a cause of failure in the conventional ink jet coating. By actively utilizing the cracks in the pattern, regardless of the pattern data,
A very natural and well-balanced spot pattern can be painted.

By the way, as the height position of the jet nozzle 17 is increased, the flight distance of the paint droplet ejected from the jet nozzle 17 becomes longer, and the time during which the paint droplet receives air resistance becomes longer. The division of the paint droplets is promoted, so that the paint droplets are divided more finely.
According to the test results of the present inventor, if the height position of the jet nozzle 17 is separated from the building board 11 by 5 cm or more, the paint droplets in flight are irregularly divided into a plurality of droplets having different particle sizes. To draw a spotted pattern. Further, if the height position of the jet nozzle 17 is separated from the building board 11 by 10 cm or more, the number of cracks of the paint droplet in flight (the number of spots formed by one jet nozzle 17) increases, and the number of spots increases. Become.
In order to create a more natural-looking balanced spot pattern, it is preferable that the height position of the jet nozzle 17 be 15 cm or more above the building board 11.

However, if the height of the jet nozzle 17 is too high, the flight path of the paint droplets is deviated from the position directly below the jet nozzle 17 under the influence of the flow of the ventilation air in the coating room. This causes problems such as uneven coating, the edge portion of the building board 11 not being painted, and the paint scattering area protruding largely from the painted surface. According to the test results of the inventor, the jet nozzle 1
It is preferable to set the height position of 7 to 50 cm or less,
If it is 50 cm or less, the spot pattern can be painted almost without being affected by the flow of ventilation air.

Further, as shown in FIG. 4, as the height position of the jet nozzle 17 increases, the scatter area of the paint droplets falling on the surface of the building board 11 increases. That is, FIG.
As shown in FIG. 4A, when the height position of the jet nozzle 17 is low, the area where the paint is scattered is small, and a small number of small spots approach a large spot.
As shown in (b), when the height position of the jet nozzle 17 increases, the spots at the center decrease, but the number of spots around the center increases, and the spots are spread and scattered.
Therefore, taking into account such features, the jet nozzle 1
The height position 7 may be appropriately set within a range of 5 cm or more according to the type of the spot pattern to be drawn.

By the way, as the opening / closing frequency of the valve 18 for opening / closing the jet nozzle 17 becomes smaller (ie, the opening / closing speed becomes slower), as shown in FIG.
8, the amount of paint sprayed per opening / closing operation increases, the spots at the center become large, and the number of small spots around the spots decreases. On the other hand, as the opening / closing frequency of the valve 18 increases (that is, the opening / closing speed increases), as shown in FIG. 3A, the amount of paint sprayed per opening / closing of the valve 18 decreases, and the spot at the center decreases. At the same time, the number of small spots around it increases. From this relationship, in order to stabilize the paint spraying state and to form a speckle pattern with a well-balanced speckle pattern, the opening / closing frequency of the valve 18 may be set to 100 to 300 times / sec. By setting the number of times per second, a spot pattern having a more natural feeling can be created.

Further, as the arrangement pitch of the jet nozzles 17 arranged in the width direction of the building board 11 increases,
The overlapping area of the scattered areas of the paint droplets ejected from each jet nozzle 17 is reduced or separated without overlapping at all, and the density of spots is reduced as shown in FIG. On the other hand, as the arrangement pitch of the jet nozzles 17 becomes smaller, the overlap of the scattering areas of the paint droplets ejected from each jet nozzle 17 becomes larger, and the density of spots becomes larger as shown in FIG. From this relationship, to make a spot pattern of moderate density,
It is preferable that the arrangement pitch of the jet nozzles 17 is set to 0.5 to 3.0 mm. In addition, the density of the spots
(That is, the spot density increases as the transport speed decreases).

In the above-mentioned coating method using a conventional spray gun, since the spray paint diffusion area is largely expanded in a circular or elliptical shape, spot patterns can be uneven due to the variation in the overlapping area of the adjacent paint diffusion areas. There were drawbacks.

In this regard, according to the above embodiment, the scattering area of the paint droplets ejected from each jet nozzle 17 is extremely small as compared with the paint diffusion area of the spray gun. Even if there is variation, it can be buried in the spot pattern and not noticeable at all, and a spot pattern with a natural feeling can be created.

According to the experimental results of the present inventor, it has been found that the size of the spots is also related to the viscosity of the paint, the surface temperature of the building board 11, and the paint spray pressure. That is, the higher the viscosity of the paint, the larger the spots, and the lower the viscosity, the smaller the spots. Also, the higher the surface temperature of the building board 11, the faster the drying of the paint and the smaller the spots, while the lower the surface temperature of the building board 11, the slower the drying of the paint and the larger the spots. Also,
As the paint spray pressure increases, the paint spray amount increases and the spray speed increases, so that the paint droplets spread on the surface of the building board 11 and the spots increase. On the other hand, as the paint spray pressure decreases, the paint spray amount decreases and the spray speed decreases, so that the spread of the paint droplets on the surface of the building board 11 decreases, and spots decrease. Therefore, the size of the speckles can be adjusted by adjusting any one of the viscosity of the paint, the surface temperature of the building board 11, and the paint injection pressure.

In the above embodiment, the same color paint is ejected from all the jet nozzles 17 arranged in a line. However, a plurality of coating heads are juxtaposed and different from the jet nozzles of each coating head. A plurality of spots may be formed by squirting color paint. Also, the present invention
As described above, a spot pattern can be created without using pattern data.However, the present invention is applied to a coating apparatus that creates a graphic pattern using pattern data, so that a spot-blurred graphic pattern is created. Is also good.

[0027]

As is apparent from the above description, according to the present invention, the height position of the jet nozzle is separated from the building board by 5 cm or more, and the opening / closing operation of the valve for opening / closing the jet nozzle is performed 100 to 300 times. since the so painted repeatedly with times / second, the paint droplets ejected from the jet nozzle building board the paint droplets during flight until it reaches the surface of a plurality of different particle sizes by the air resistance Divided into droplets, it is possible to paint a speckle pattern in which the size of the spot changes irregularly, and it is possible to paint a well-balanced speckle pattern with a very natural feeling, regardless of the pattern data .

In this case, if the opening / closing frequency of the valve for opening / closing each jet nozzle is set to 100 to 300 times / second,
The number of paint droplets in flight and the particle size of the broken droplets can be made suitable for spot pattern formation.

Furthermore, if the arrangement pitch of the jet nozzles arranged in the width direction of the building board is set to 0.5 to 3.0 mm, the jets are jetted from the jet nozzles arranged at a height of 5 cm or more. The scattering areas of the paint droplets overlap moderately, and the spot density does not need to be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a coating apparatus showing an embodiment of the present invention.

FIG. 2 is a side view showing a positional relationship between a conveyor and a jet nozzle.

FIG. 3 is a diagram for explaining the relationship between the opening / closing frequency of a valve and the size of spots.

FIG. 4 is a view for explaining the relationship between the height of a jet nozzle and the area in which paint droplets are scattered.

FIG. 5 is a diagram illustrating a difference in spot density.

[Explanation of symbols]

11 ... Construction board, 12 ... Conveyor (transportation means), 14 ... Emitter, 15 ... Receiver, 16 ... Coating head, 17 ... Jet nozzle, 18 ... Valve, 20 ... Paint tank, 21 ... Co
Compenser , 22 ... Regulator .

Claims (3)

(57) [Claims] 1. A building board coating method for coating a spot pattern by spraying paint from a plurality of jet nozzles arranged to cover the entire width of the surface of the building board conveyed by the conveying means. Then, the height position of each jet nozzle is separated by 5 cm or more above the building board, and the opening / closing operation of the valve for opening / closing the jet nozzle is repeated at 100 to 300 times / sec. During the flight until the paint droplets reach the surface of the building board, the paint droplets are irregularly divided into a plurality of droplets having different particle diameters, and the surface of the building board has spots. A method for painting a building board, characterized in that a spot pattern whose size changes irregularly is painted. 2. A method according to claim 1, characterized in that setting the array pitch of each jet nozzle 0.5~3.0mm
The method of painting a building board described in. 3. A transport means for transporting the building boards, arranged at intervals of 0.5 to 3.0 mm in the width direction of the building boards to be transported, and arranged at a distance of 5 cm or more above the building boards. A plurality of jet nozzles, and a valve that opens and closes each of the jet nozzles at a rate of 100 to 300 times / second.