JPH0240382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method that reduces color change time.

Conventionally, a rotary atomizing electrostatic coating device that changes colors has a plurality of different pressurized paint sources, and a pressurized cleaning liquid source and pressurized air source that clean the spray head and paint supply pipe when changing paint colors. Each is provided with
Any one of them was selected by a color switching device and communicated with one supply pipe extending from the color switching device into the spray head of the main body of the rotary atomizing electrostatic coating device. Then, with the above configuration, the paint is supplied from the paint supply pipe and the paint is sprayed from the spray head, and the paint that is attached to the spray head and the paint supply pipe is removed before switching to a new paint color. A cleaning process was carried out to clean the paint.

Therefore, when moving from the cleaning process to a new painting process, there is only one paint supply pipe extending into the spray head, so after the cleaning process is finished, the color switching device switches to another pressurized paint source. It is necessary to communicate with the paint supply pipe, and the paint supply pipe from the color switching device to the spray head is long, so it takes a considerable amount of time for the paint to be supplied into the spray head after the cleaning process is completed. This takes time, and as a result, the so-called color change time is lengthened.

The present invention aims to solve the above-mentioned problems, and its purpose is to provide a coating method that reduces color change time.

The feature of this invention is that in a coating method in which paint is supplied to the main body of a rotary atomizing electrostatic coating apparatus through a supply pipe, after the supply of one paint that has been supplied from one supply pipe is stopped, Pressurized air and a cleaning liquid are supplied to the supply pipe of said one to clean said one supply pipe and the main body of the rotary atomizing electrostatic coating apparatus, and after the supply of said one paint from said one supply pipe is stopped, said cleaning step Another paint is supplied from another supply pipe inside the apparatus, and after the cleaning process is completed, the other paint is supplied from the other supply pipe to the main body of the rotary atomization electrostatic coating apparatus. be.

Examples of the coating method of the present invention will be described below.

In FIG. 1, 1 is the main body of the rotary atomizing electrostatic coating device, 2 is the housing of the main body 1, and the housing 2 has a rotating shaft extending outward from inside the housing 2 (to the left in FIG. 1). 3 is rotatably supported, and a cup-shaped spray head 4 is fixed to this rotating shaft 3 with a nut 5. Rotating shaft 3 is from -60KV-
It is connected to a high voltage generator (not shown) that generates a negative high voltage of 120 KV, so that a negative high voltage is applied to the cup-shaped spray head 4 via the rotating shaft 3. .

As shown in FIG. 1, the cup-shaped spray head 4 has a cup-shaped inner circumferential surface 6 and an annular space 7 formed around the rotating shaft 3, and within this annular space 7, the nozzles of the paint injection nozzles 8 and 9 are arranged. Mouths 10 and 11 are open,
The nozzles 8 and 9 are connected to color switching devices 12 and 13, which will be described later.
They are connected to supply pipes 14 and 15 extending from the base, respectively. Further, a large number of paint outlet holes 16 are formed at the innermost part of the annular space 7 over the entire circumference thereof. Furthermore, a shroud 1 is provided around the cup-shaped spray head 4 so as to surround the cup-shaped spray head 4.
7 is provided, and the bottom of this shroud 17 is connected via a drainage conduit 18 to a drainage tank 19 . This shroud 17 is provided so as to be movable back and forth.During the painting process, it is moved back so as not to interfere with the painting process, and during the cleaning process, it is moved forward to keep the cleaning fluid and air at a high level for cleaning. Even if it is released under pressure, this shroud 17 can catch it and prevent it from scattering to the surroundings.

20, 21, and 22 are pressurized paint sources each having a different paint color; 23 is a pressurized cleaning liquid source; and 24 is a pressurized air source.

One of them, the pressurized paint source 20, includes color switching devices 12, 13 and piping 20a, 20b, respectively.
The color switching device 12,1 is connected via the color switching device 12,1.
3 are valves 12a and 13a installed in the middle of the piping.
The pipes 20a, 20b and the supply pipe 1 are opened and closed.
4 and 15 are controlled.

Similarly, the pressurized paint sources 21 and 22, the pressurized cleaning liquid source 23, and the pressurized air source 24 are connected to the color switching device 12,
13 and piping 21a, 21b, 22a, respectively.
22b, 23a, 23b, 24a, 24b.
3c, 12d, 13d, 12e, 13e, the pipes 21a, 21b, 22a, 22b,
23a, 23b, 24a, 24b and supply pipe 14,
15.

Incidentally, the systematic opening and closing operations of each of the above-mentioned valves are controlled by the color switching device 12,
13.

Next, the operation of the above structure will be explained step by step based on the time chart shown in FIG. 2 showing the opening and closing states of each valve.

During step, valve 12a is open and all other valves are closed. That is, only the paint of the color sent from the pressurized paint source 20 is sent to the pipe 20a, the valve 12a, the color switching device 12, and the supply pipe 14.
is supplied to the annular space 7, where the paint is negatively charged and sprayed out through the paint outlet holes 16 of the rotating cup-shaped spray head 4. At this time,
The shroud 17 has been retracted to the position shown by the imaginary line in FIG.

When the painting process is completed using the pressurized paint source 20, the process moves on to step 1, where the valve 12a is closed and at the same time, the valve 12a is closed.
2e is opened, and pressurized air from the pressurized air source 24 is sent to the annular space 7 via the pipe 24a, the valve 12e, the color switching device 12, and the supply pipe 14, and the pressurized paint source remaining in the route is sent to the annular space 7. 20 paint is extruded from the paint outlet hole 16 of the cup-shaped spray head 4, and the paint adhering to the cup-shaped spray head 4 is also removed.

At this time, the shroud 17 moves to the position shown by the solid line in FIG. 1, and the high voltage from the high voltage generator is no longer applied to the cup-shaped spray head 4. Therefore, the extruded paint loses the electrostatic attraction force and is only subjected to centrifugal force, scattering from the cup-shaped inner peripheral end in the circumferential direction and being captured by the shroud 17.

After a certain period of time has elapsed and you move on to the step, valve 1
2e is closed, and at the same time, the valve 12d is opened, and the cleaning liquid is supplied from the pressurized cleaning liquid source 23 to the annular space 7 via the pipe 23a, the valve 12d, the color switching device 12, and the supply pipe 14, and the cleaning liquid remains in the path. Alternatively, the adhering paint is dissolved and washed and extruded from the paint outlet hole 16 of the cup-shaped spray head 4. The extruded cleaning liquid and the like are captured by the shroud 17 and discharged to the drain tank 19 via the drain pipe 18 while also cleaning the shroud 17 itself.

When moving to the step, the valve 12d closes and at the same time the valve 12e opens again, taking the same movement as the step.

On the other hand, the color switching device 13 opens the valve 13b at a certain point in the progress of the above-mentioned steps ~, and transfers paint of the paint color from the pressurized paint source 21 to the pipe 21b and the valve 13.
b, sent to the annular space 7 via the color switching device 13 and the supply pipe 15;

The timing of opening this valve 13b is such that the paint from the pressurized paint source 21 reaches the annular space 7 in the cup-shaped spray head 4 after the step is completed.

When moving to the step, a high voltage is again applied to the cup-shaped spray head 4, and the shroud 17 is retreated to the position indicated by the imaginary line in FIG. And pressurized paint source 21
The paint is sprayed while being electrically charged from the paint outlet hole 16 of the cup-shaped spray head.

When moving to the step, the valve 13b is closed and the valve 13e is opened at the same time, and pressurized air from the pressurized air source 24 is sent to the annular space 7 via the pipe 24b, the valve 13e, the color switching device 13, and the paint supply pipe 14. The paint is pushed out along the route, and the paint adhering to the cup-shaped spray head 4 is also removed.

At this time, the shroud 17 moves to the position shown by the solid line in FIG. 1, and the high voltage from the high voltage generator is no longer applied to the cup-shaped spray head 4. Therefore, the extruded paint is subjected to only centrifugal force, scatters in the circumferential direction from the cup-shaped inner peripheral end, and is captured by the shroud 17.

When moving to step, the valve 13e closes and at the same time the valve 13d opens, and the cleaning liquid is supplied from the pressurized cleaning liquid source 23 to the annular space 7 via the pipe 23b, the valve 13d, the color switching device 13, and the supply pipe 15. The remaining or attached paint is dissolved and washed and extruded from the paint outlet hole 16 of the cup-shaped spray head 4. The extruded cleaning liquid etc. is captured by the shroud 17, and the shroud itself is also cleaned while being drained into the drain pipe 18.
The liquid is discharged to the drainage tank 19 through the drain tank 19.

When moving to step, valve 13d closes and at the same time valve 1
3e opens again and takes the same movement as the step.

On the other hand, the color switching device 12 opens the valve 12c at a certain point in the progress of the steps ~, and supplies the paint from the pressurized paint source 22 to the annular space 7 through the pipe 22a, the valve 12c, the color switching device 12, and the supply pipe 14. send to

The valve 12c is opened at a timing such that the paint from the pressurized paint source 22 reaches the annular space 7 in the cup-shaped spray head 4 after the step is completed.

When moving to the step, a high voltage is again applied to the cup-shaped spray head 4, and the shroud 17 is retreated to the position indicated by the imaginary line in FIG. And pressurized paint source 22
The paint is sprayed from the paint outlet hole 16 of the cup-shaped spray head 4 while being electrically charged.

Incidentally, such a series of operations is stored in a central control device (not shown), and the central control device issues commands corresponding to each step.

Next, another embodiment of the rotary atomization type electrostatic coating apparatus will be described. Hereinafter, the same components as those in the above embodiment will be denoted by the same reference numerals, and the explanation thereof will be omitted.

As shown in FIG. 3, a supply pipe 25 is added to the above embodiment to connect the pressurized cleaning liquid source and the inside of the cup-shaped spray head 4, and a valve 26 is provided in the middle of the supply pipe 25. It is provided. In this embodiment, as is clear from the time chart shown in FIG. 4, the valve 26 is opened from step to step until the end of the step, and the cleaning liquid is sent into the annular space 7 through the pipe 25 and the valve 26. .

Therefore, a large amount of cleaning liquid can be sent compared to the above embodiment, and the cleaning effect of the annular space 7, the cup-shaped spray head 4, and the shroud 17 is greatly improved, especially in preventing so-called dripping of paint from the shroud. This makes it possible to improve cleaning time and shorten cleaning time.

FIG. 5 shows an embodiment of a rotary atomizing electrostatic coating apparatus for carrying out the coating method of the present invention, in which the paint source 20 is
The color switching device 2 is connected to the color switching device 2 through the valve 27a by the piping 20d.
7, and a supply pipe 28 extends into the cup-shaped spray head 4 from the outlet of the color switching device 27.

The other pressurized paint sources 21, 22 are similarly connected only to the color switching devices 29, 30 via valves 29a, 30a by pipes 21a, 22a, respectively, and are connected from the outlet of the color switching devices 29, 30 to the supply pipe 31. ,32
extend into the spray head 4, respectively.

The cleaning liquid source 23 has each color switching device 27, 29, 30.
and valve 27b, by pipes 23a, 23b, 23c.
Similarly, the air source 24 is connected to the color switching devices 27, 29, and 30 via valves 27c, 29c, and 30c via pipes 24a, 24b, and 24c, respectively.

As is clear from the time chart shown in FIG. 6, the operation of this embodiment is similar to that of an embodiment of the rotary atomization electrostatic coating apparatus (see FIG. 2).

FIG. 7 shows another embodiment of the rotary atomizing electrostatic coating device, which is shown in one embodiment of the rotary atomizing electrostatic coating device. A supply pipe 25 equipped with a valve 26 is added to directly connect the cleaning liquid source 23 and the inside of the spray head 4.

As shown in the time chart of FIG. 8, this embodiment has the same operation as the other embodiment of the rotary atomization electrostatic coating apparatus (see FIG. 4).

Although several embodiments have been described above, the present invention is not limited to the above embodiments, but also includes the following embodiments.

During the cleaning process, pressurized air and pressurized cleaning liquid may be alternately supplied to the cup-shaped spray head in pulses.

The number of supply pipes is not limited to two or three, but any number may be used.

As is clear from the above, in the coating method of the present invention, new paint is supplied from another supply pipe during the cleaning process of one supply pipe, and after the cleaning of the first supply pipe is completed, the new paint is supplied to the other supply pipe. Since new paint is supplied to the main body of the rotary atomization electrostatic coating device from the supply pipe, the time required for color change can be shortened.

In addition, the rotary atomization type electrostatic coating device that implements the above method has a simple structure that only requires first and second supply pipes connected to the rotary atomization type electrostatic coating device body, and can change multiple colors. Moreover, the color change time can be shortened.

Furthermore, in the rotary atomizing electrostatic coating equipment that implements the above method, the color switching device and paint supply pipe are connected independently for each paint source, so there is no color mixing and the time required for color change is reduced. Can be shortened.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram showing an embodiment of a rotary atomization type electrostatic coating device that implements the coating method of the present invention, and Fig. 2 is a timetable diagram of the rotary atomization type electrostatic coating device shown in Fig. 1. 3 is a conceptual diagram showing another embodiment of the rotary atomization electrostatic coating device, and FIG. 4 is a conceptual diagram showing another embodiment of the rotary atomization electrostatic coating device.
FIG. 3 is a time chart of the rotary atomization type electrostatic coating device, FIG. 5 is a conceptual diagram showing an embodiment of the rotary atomization type electrostatic coating device that implements the coating method of the present invention, and FIG. 6 5 is a time chart of the rotary atomization type electrostatic coating device, FIG. 7 is a conceptual diagram showing another embodiment of the rotary atomization type electrostatic coating device, and FIG. 8 is a time chart of the rotary atomization type electrostatic coating device of FIG. This is a time chart of a rotary atomization electrostatic coating device. 1...Rotary atomization electrostatic coating device main body, 12,1
3, 27, 29, 30...color switching device, 14, 1
5, 28, 31, 32...Paint supply pipe, 20, 2
1, 22... Pressurized paint source, 23... Pressurized cleaning liquid source, 2
4... Pressurized air source, 25... Cleaning liquid dedicated pipe.

Claims (1)

[Scope of Claims] 1. In a coating method in which paint is supplied to the main body of a rotary atomization electrostatic coating device via a supply pipe, after the supply of one paint that has been supplied from one supply pipe is stopped, Supplying pressurized air and cleaning liquid to the first supply pipe to clean the first supply pipe and the main body of the rotary atomization electrostatic coating device, and after stopping the supply of the first paint from the first supply pipe. During the cleaning process, another paint is supplied from another supply pipe, so that after the cleaning process is completed, the other paint is supplied to the main body of the rotary atomization electrostatic coating device. A painting method characterized by: 2. The coating method according to claim 1, wherein the cleaning liquid is supplied to the main body of the rotary atomization electrostatic coating apparatus through a supply pipe other than the one and other supply pipes during the cleaning step.