JP3338580B2 - Multicolor electrostatic coating machine for powder coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center feed type for supplying powder paint to a rotary spray head attached to a tip of a tubular rotary shaft through a paint flow passage inserted through a tubular rotary shaft of an air motor. The present invention relates to a multicolor electrostatic coating machine for powder coating.

[0002]

2. Description of the Related Art For example, in a coating line for an automobile body, a coating must be performed in a predetermined color for each object to be conveyed one after another by a conveyor, and a solvent paint in which a paint component is dissolved in a solvent. In the case of performing multi-color electrostatic coating, a color changing device 82 is connected to an electrostatic coating machine 81 via a paint hose 83 as shown in FIG. Is supplied to a rotary atomizing head 87 through a thin tubular nozzle 86 inserted through a tubular rotary shaft 85 of an air motor 84 of an electrostatic coating machine 81 (Japanese Utility Model Laid-Open No. 2-112353, 4-9175
No. 4).

On the other hand, when electrostatic coating is performed using a powder coating, the powder coating is supplied in a state of being suspended in an air current. If the coating flow path is bent, the powder coating is accumulated in the bent portion,
When this grows, a lump of paint is sprayed to cause a coating defect called lumps.Therefore, a valve having a complicated flow path like a normal paint or a color changing device using such a valve is interposed in the flow path. Can not do it.

In this case, as shown in FIG. 9, a plurality of narrow nozzles 90, 9 to which powder coating materials of respective colors are individually supplied.
Is inserted into the tubular rotary shaft 93 of the air motor 92 of the electrostatic coating machine 91 and paint is supplied from one thin tubular nozzle 90 to the rotary spray head 94, and a color changing device is interposed in the paint flow path. Multicolor electrostatic coating of the powder coating becomes possible without performing.

[0005]

However, since the powder paint is suspended in an air stream and supplied together with high-pressure air, when the powder paint is supplied from a single tubular nozzle, the pressure in the rotary spray head is reduced. At the same time, a part of the supplied powder paint flows back from the tip opening of the other tubular nozzle by air pressure and is blown deep into the paint hose. Since it adheres to the surface or mixes with the powder paint remaining inside, there is a problem that when the color is changed and the next color paint is applied from the other thin tubular nozzle, coating failure due to color mixing occurs. Was.

For this reason, when changing colors, first, in order to remove the other color paint blown into the thin tubular nozzle, cleaning air is supplied or powder paint is discarded and blown. , If blown deep into the paint hose,
In addition to the time required for cleaning, there remains a problem that a large amount of powder paint must be discarded and blown.

In the case of a conventional solvent paint, a needle valve for opening and closing the opening is formed at the tip of each of the narrow nozzles, and a driving device is arranged at the rear end of the narrow nozzle. By forming the paint flow path so as to avoid it, backflow of the paint can be prevented.However, in the case of powder paint, the paint flow path cannot be bent, so the tip opening of each capillary nozzle Neither can a needle valve for opening and closing the part be formed. Therefore, the present invention provides a method in which the powder coating material supplied from one thin-tube nozzle extends from the tip opening of another thin-tube nozzle to the back without forming a needle valve at the tip opening of each thin-tube nozzle. It is an object of the present invention to reduce the washing time, prevent color mixing, and eliminate waste of paint by preventing backflow.

[0008]

In order to solve this problem, a first aspect of the present invention is a rotary motor attached to the tip of the tubular rotary shaft via a paint flow passage inserted through the tubular rotary shaft of an air motor. In a center-feed type multi-color electrostatic coating machine for powder coating which supplies powder coating to a spray head, a plurality of narrow nozzles serving as a coating flow path for supplying powder coating to a rotary spray head are formed by the tubular rotary nozzle. While being inserted into the shaft of the shaft in a non-contact state, the paint tubes are connected to respective paint supply tubes via an elastic tube to supply the powder paints of the respective colors from the paint supply source in a floating manner. Opening / closing valves are provided for each paint flow path to conduct and shut off the narrow tubular nozzle and the paint supply pipe connected thereto by individually applying pressure from the surroundings and crushing the space in the elastic pipe. It is characterized by.

According to a second aspect of the present invention, a plurality of thin tubular nozzles serving as a paint flow path for supplying a powder paint to a rotary spray head are provided.
While being inserted in a non-contact state into the axis of the tubular rotary shaft, the nozzle holes are arranged in an annular shape toward the rotating spray head, and the nozzle holes are arranged in an annular shape on the front side of the thin tubular nozzle. A shutter disk formed with a hole or a notch for opening only the nozzle hole of one of the thin tubular nozzles is rotatably mounted around a rotation axis disposed at a center position of the annular arrangement. Features.

Further, according to a third aspect of the present invention, a plurality of narrow nozzles serving as a paint flow path for supplying a powder paint to a rotary spray head are inserted through the tubular rotary shaft in a non-contact state. Each of the thin tubular nozzles is switchably connected to a paint supply source for supplying the powder paint in a state of being suspended in an air stream and a cleaning air supply source for supplying cleaning air. Only the powder paint of any color is supplied to the rotary spray head connected to the paint supply source, and all the other tubular nozzles are connected to the cleaning air source to rotate the cleaning air at a predetermined pressure. It is characterized by being supplied to a spray head.

[0011]

According to the first aspect of the present invention, when the powder paint is supplied from one of the thin tubular nozzles to supply the paint, the powder paint is supplied from the paint supply pipe through the elastic pipe into the rotary spray head. Is done. At this time, the rotating spray head is at a high pressure, but the elastic tube connected to the other thin-tube nozzle is pressurized to crush the space in the elastic tube, and the thin-tube nozzle and the paint connected thereto are crushed. Since the supply pipe is shut off, no airflow toward the inside of the thin-tube nozzle is formed, and the powder paint adheres to the tip side of the thin-tube nozzle, and does not flow back to the inside of the nozzle. Absent.

According to the second aspect of the present invention, the tip openings of the plurality of narrow nozzles inserted into the tubular rotary shaft of the air motor are arranged in a ring shape toward the rotary spray head, and are selected on the front side thereof. A shutter disk formed in a shape that covers all other openings except for one opening is rotatably disposed, and the shutter disk is rotated,
If only the opening of any one of the narrow nozzles is opened, the openings of the other thin nozzles are closed by the shutter disk. Does not flow back into the narrow nozzle.

According to the third aspect of the present invention, each of the narrow nozzles is switchably connected to a paint supply source for supplying the powder paint by floating it in an air flow and a cleaning air supply source for supplying the cleaning air. At the time of painting, only one selected tubular nozzle is connected to the paint supply source to supply powder paint of any color to the rotary spray head, while all other tubular nozzles are connected to the cleaning air supply source. And the cleaning air is supplied to the rotary spray head at a predetermined pressure, so that the powder coating material does not flow back into another narrow nozzle against the flow of the cleaning air.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 1 is a side view showing an example of a multicolor electrostatic coating machine for powder coating according to the present invention, FIG. 2 is a sectional view showing a main part thereof, FIG. 3 is a side view showing another embodiment, and FIG. FIG. 5 is a cross-sectional view showing the main part, FIG. 5 is a side view showing another multi-color electrostatic coating machine for powder coating according to the present invention, FIG. 6 is a cross-sectional view showing the main part, and FIG. 9 is a flow sheet showing still another multicolor electrostatic coating machine for powder coating.

In FIG. 1, reference numeral 1 denotes an electrostatic coating machine in which a rotary spray head 5 is attached to the tip of a tubular rotary shaft 4 of an air motor 3 built in a housing 2. around the cleaning fine tubular nozzle N ₀ supplies, white therearound, red, gray, blue, each color of the powder coating individually rotating spray head supplies a plurality of paint fine tubular nozzle N such as black _{1 to} N ₆ are inserted in a non-contact state.

Then, the coating thin tubular nozzles N _{1 to} N
Numeral ₆ denotes respective paint supply pipes 6, 6,... For supplying powder paint of each color in a gas stream from a paint supply source (not shown).
To be connected via the elastic tube 7, 7, even cleaning fine tubular nozzle N ₀ is connected to the wash air supply pipe 8 via the elastic tube 7 as well.

Further, V _{0 to} V ₆ are used to pressurize and flatten each of the elastic pipes 7 from the periphery thereof, thereby connecting the thin tubular nozzles N _{0 to} N ₆ and the paint supply pipe connected thereto. An open / close valve for conducting / cutting off, wherein each elastic tube 7 is
The elastic pipes 7 are respectively inserted into the pressurized pipes 9 whose interiors are sealed, and compressed air is individually supplied into the pressurized pipes 9 to pressurize and flatten the elastic pipes 7 by the air pressure, thereby narrowing the narrow nozzles N _{1 to} N _{1. 6} is connected and disconnected from the paint supply pipe 6 and the cleaning air supply pipe 7 connected thereto. Reference numeral 10 denotes a compressed air supply source for individually supplying compressed air into each pressurized pipe 9, reference numeral 11 denotes a high voltage generator for applying a high voltage to the rotary spray head 5, and reference numeral 12 denotes powder adhered to the outer periphery of the housing 2. An air shower device that blows off body paint.

The above is an example of the configuration of the present invention.
The action of, for example, ₁White supplied by
From the paint, a thin tubular nozzle N_TwoRed paint supplied in color
The case of replacement will be described. Before painting, pressurize
The compressed air is supplied into the pipe 9 to pressurize and flatten the elastic tube 7.
By opening and closing each valve V₀~ V₆Is closed.

At the time of coating, first, driving air is supplied to the air motor 3 to rotate the rotary spray head 5 attached to the tubular rotary shaft 4 at high speed, and at the same time, apply a high voltage to the rotary spray head 5. Apply. Next, the on-off valve V ₁
When the supply of the compressed air to the paint is stopped and the white powder paint is fed from the paint supply source, the flattened elastic tube 7 expands due to its own elastic force and the feeding pressure of the powder paint. the supply pipe 6 and the fine tubular nozzle N ₁ is conductive, the white paint is supplied to the rotary atomizing head 5 from the fine tubular nozzle N _1.

[0020] At this time, the paint flow path from the paint supply tube 6 through the elastic tube 7 in fine tubular nozzle N _1, is only a gradual bend, because there is no sharp bending portion, powder coating It is supplied uniformly without stagnation. Also, air flow directed from the coating material supply source for supplying powder coating material to the fine tubular nozzle N ₁ is formed, becomes the high pressure in the rotary spray head 5 by the air flow, the other of the opening and closing valve V _0, V since the ₂ ~V ₆ elastic tube 7 each is supplied with compressed air is flatly collapsed, as shown in FIG. 2, other fine tubular nozzle N _0, N ₂ ~
N ₆ , the respective paint supply pipes 6 and the cleaning air supply pipes 7 are shut off, so that no air flow flowing into the other narrow nozzles N ₀ , N _{2 to} N ₆ is formed. Therefore, the powder paint only adheres to the tip end of the thin tubular nozzles N ₀ , N _{2 to} N ₆ at best, and does not blow into the interior of the nozzle, but penetrates into the paint supply pipe 6 and the cleaning air supply pipe 8. I will not do it.

[0021] When the coating according to the white paint is completed, the supply of paint from the paint supply source is stopped, after discarding the remaining paint by injecting air from the fine tubular nozzle N _1, compressed air to the opening and closing valve V ₁ by supplying closing the valve V _1. Next, the supply of the compressed air to the opening / closing valve V ₀ is stopped, the valve V ₀ is opened, and the cleaning air is supplied into the rotary spray head 5 to remove the white paint remaining in the rotary spray head 5 and to open and close. fine tubular nozzle N to stop the supply of compressed air to the valve V ₂ is used then open the valve V _2
2 is jetted air from, to completely remove the white paint adhering to the fine tubular nozzle N _2.

At this time, since the white paint is attached only to the tip ends of the thin-tube nozzles N _{0 to} N ₆ , the cleaning time is short, the white paint can be removed very easily, and the next color paint is applied. Sometimes does not cause color mixing. In addition,
In this washing step, only the white paint is discharged, so that it can be collected and reused. And
Compressed air is supplied to the valves V ₀ , V ₁ , V _{3 to} V ₆ other than the opening / closing valve V ₂ , and in a state where each valve is closed, the apparatus waits until the next object to be coated arrives. where arriving performs coating by supplying a red paint fine tubular nozzle N _2.

FIG. 3 is a side view showing another embodiment, and FIG. 4 is a cross-sectional view showing a main part thereof. Parts common to FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted. . In this example,
The open / close valves V _{0 to} V ₅ are each composed of a stator 21 having a groove 20 through which the elastic tube 7 is inserted, and a cylinder 24 in which a presser 22 for crushing the elastic tube 7 is attached to the tip of a piston rod 23. When extending the rod 23, since the elastic tube 7 is collapsed pressure in the groove 20 in the pressure against being mechanically, the valves V ₀ ~V ₅ is closed, when the piston rod 23 is contracted, have collapsed The elastic tube 7 is expanded and opened by its own elastic force and the feeding pressure of the powder coating material.

FIG. 5 is another multi-color electrostatic coating machine for powder coating according to the present invention, and FIG. 6 is a perspective view showing the main part thereof.
2 are denoted by the same reference numerals, and detailed description is omitted. In this example, five coating narrow nozzles N _{1 to} N _{5 serving} as a coating flow path for supplying a powder coating to the rotary spray head ₅ and a cleaning thin nozzle N ₀ for supplying cleaning air are formed by the tubular member. The rotary shaft 4 is inserted through the shaft of the rotary shaft 4 in a non-contact state, and its tip is supported by the rotary spray head in a non-contact state and is connected to the nozzle head 31 collectively.

The nozzle head 31 has respective nozzles N _{0 to} N
With ₅ of the nozzle hole H ₀ to H ₅ · · are formed in an annular shape so as to face the rotary atomizing head 5, through holes 32 that the front side to open only one nozzle hole of the fine tubular nozzle Alternatively, a notched shutter disk 33 is provided with a motor 35 around a rotating shaft 34 disposed at the center position of the annular arrangement.
It is mounted so that it can rotate.

According to the present embodiment, the narrow nozzle N₁Supplied by
From the white paint to be used _TwoRed supplied by
When changing the color to paint, first, drive air to the air motor 3
And the rotary spray attached to the tubular rotary shaft 4
High-speed rotation of the head 5 and high voltage
Is applied. Then, rotate the shutter disk 33.
And the through-hole 32 is inserted into the thin tubular nozzle N ₁Nozzle hole H₁To
When the white powder paint is fed from the paint source,
White paint is a thin tubular nozzle N₁Supplied to the rotary spray head 5 from
It is.

At this time, in order to supply the powder coating material, an air flow is formed from the coating material supply source toward the thin-tube nozzle N _1, and the pressure inside the rotary spray head 5 is increased by this air flow.
Since the nozzle holes H ₂ to H ₆ other fine tubular nozzle N ₂ to N ₆ is closed by the shutter disk 33, the white paint from flowing back, of course, fine tubular nozzle N ₂ to N ₆
It does not adhere to the tip side of

When the coating with the white paint is completed, the supply of the paint from the paint supply source is stopped, and then the shutter disk 33 is rotated to move the through-hole 32 into the nozzle hole H ₀ of the cleaning thin-film nozzle N _0. In addition, cleaning air is supplied to remove the white paint adhering in the rotary spray head 5. Note that in this cleaning process, there is no need to discard the white paint remaining in the fine tubular nozzle N _1, insufficient by removing only paint adhered to the rotary atomizing head 5, yet in this case, white coating only Can be collected and reused, so that there is no waste of paint.

[0029] When the washing in the rotary spray head 5 is completed, waits to rotate the shutter disk 33, together the through hole 32 to the nozzle hole of H ₂ fine tubular nozzle N _2, the next object to be coated is reached Then, when it arrives, the thin tubular nozzle N
₂₎ Red paint is supplied from a paint supply source to perform painting. At this time, since the leading end of the thin tube-like nozzle N ₂ white paint does not adhere, can amount to blow discarded to save significantly less finished paint.

FIG. 7 shows still another embodiment according to the present invention.
1 and 2 in the flow sheet
The same reference numerals are used for the same components, and detailed description is omitted. In this example
Is a thin nozzle for coating N₁~ N₆Supplies powder paint
Paint source P₁~ P₆And supplying cleaning air
Air supply source A₁~ A₆Is the switching valve CV ₁~ CV₆Through
And are switchably connected.

The switching valves CV _{1 to} CV ₆ are, for example, as shown in FIG.
As shown in FIG. 5, an output port 41 for supplying paint and air to the thin-tube nozzles N _{1 to} N ₆ , a paint input port 42 for receiving paint from paint supply sources P _{1 to} P ₆ , a cleaning air supply source An air input port 43 for receiving air supply from A _{1 to} A ₆ , and the output port 41 and the paint input port 4
2, the air input port 43 is arranged at a predetermined angle with respect to the output boat 41, and the paint input port 42 or the air input port 43 is selectively communicated with the output port 41. Channels 44 and 4
The valve body 46 forming 5 is rotatably disposed. When the paint input port 42 and the output port 41 communicate with each other via the flow path 44, the paint flow path is formed in a straight line, so that the powder paint does not accumulate. The paint is not sprayed and does not cause paint failure.

Reference numeral 47 denotes each of the switching valves CV _{1 to} CV _6.
A control device for operating a selected one of the thin-tube nozzles at the time of coating to supply a powder paint of an arbitrary color to the rotary spray head by connecting only one selected thin-tube nozzle to the paint supply source, and all other thin-tube tubes. The nozzle is connected to a cleaning air supply source so that cleaning air is supplied to the rotary spray head 5 at a predetermined pressure.

According to this, when performing coating of white paint supplied for example by fine tubular nozzle N _1, when only the fine tubular nozzle N ₁ is connected to a paint supply source P ₁ at the same time,
All other thin tubular nozzles N _{2 to} N ₆ are connected to the cleaning air supply source A.
By connecting to the ₂ to A _6, and at the same time with respect to the rotation atomizing head 5 to supply white paint from the fine tubular nozzle N _1, supplies the cleaning air from the other fine tubular nozzle N ₂ to N ₆ at a predetermined pressure.

At this time, in order to supply a white paint,
Source P₁From thin tubular nozzle N₁Rotating spray head 5 through
An inward airflow is formed and other tubular nozzles
Le N _Two~ N₆From the air flow toward the rotary spray head 5
The white paint is at most a thin tubular nozzle N₁
~ N₆From the inside of the rotating spray head 5
Each capillary nozzle N₁~ N₆Backflow of powder paint inside
There is no.

When the coating with the white paint is completed, the switching valves CV _{1 to} CV ₆ are all set to the cleaning air supply source A.
_{1 to} A ₆ , the cleaning air is supplied into the rotary spray head 5 to remove the white paint remaining in the rotary spray head 5. At this time, since the white paint is adhered only to the tip ends of the thin-tube nozzles N _{1 to} N ₆ , the washing time is short, the white paint can be removed very easily, and the color when the next color paint is applied. It does not cause illness. In this washing step, only the white paint is discharged, so that the white paint can be collected and reused.

[0036] When the wash in the rotary spray head 5 is completed, where this time connected only switching valve CV ₂ to the paint supply source P _2, and waits for the next article to be coated arrives, arrived, tubules performing coating by supplying a red paint Jo nozzle N _2. At this time, since the white paint on the tip of the capillary-like nozzle N ₂ is not attached, is necessary to blow discarded rather, it is possible to save paint.

[0037]

As described above, according to the first aspect of the present invention, the elastic tube connected to the thin-film nozzle to which the paint is not supplied is pressurized and crushed, whereby the thin-film nozzle and Since the connected paint supply pipe is shut off, no airflow toward the inside of the narrow nozzle is formed, and the powder paint supplied from the selected narrow nozzle adheres to the tip side of the narrow nozzle. As a result, there is no backflow to the depth, and therefore, there is an effect that the washing time can be shortened at the time of color change, and that color mixing can be prevented.

According to the second aspect of the present invention, by rotating the shutter disk, only the nozzle hole of any one of the thin tubular nozzles is opened, and the nozzle holes of the other thin tubular nozzles are opened by the shutter disk. The powder coating supplied from one thin-tube nozzle does not flow back into the other thin-tube nozzle, and the powder coating does not adhere to the tip of another thin-tube nozzle. In addition, there is an effect that the washing time can be shortened at the time of color change, and that color mixing can be reliably prevented.

Further, according to the third aspect of the present invention, at the time of coating, the powder coating material is supplied to the rotary spray head from one of the selected narrow nozzles, and all the other thin nozzles are washed at a predetermined pressure. Since the air is supplied to the rotary spray head, the powder paint supplied to the rotary spray head does not flow back to the other capillary nozzle against the cleaning air flow, and in this case,
There is an effect that the washing time at the time of color change can be shortened and color mixing can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a multicolor electrostatic coating machine for powder coating according to the present invention.

FIG. 2 is a sectional view showing a main part thereof.

FIG. 3 is a side view showing another embodiment.

FIG. 4 is a sectional view showing the main part.

FIG. 5 is a side view showing another multicolor electrostatic coating machine for powder coating according to the present invention.

FIG. 6 is a perspective view showing a main part thereof.

FIG. 7 is a flow sheet showing another multicolor electrostatic coating machine for powder coatings according to the present invention.

FIG. 8 is a schematic explanatory view showing a conventional apparatus.

FIG. 9 is a schematic explanatory view showing a conventional apparatus.

[Explanation of symbols]

1 ... Electrostatic coating machine 2 ... Housing 3 ... Air motor 4 ... Tube rotary shaft 5 ... Rotation spray head N ₁ to N ₆ · · · fine tubular nozzle 6 ....... paint supply pipe 7 ....... elastic tube V ₁ ~V ₆ · · · off valve 9 ..... ··· Pressure pipes H _{0 to} H ₅ ··· Nozzle hole 32 ········································· Shutter disk 34 ········ Rotating axis P _{1 to} P ₆ .... paint supply source A ₁ to A ₆ .... wash air supply source CV ₁ ~CV ₆ ·· switching valve 47 ....... controller

Continuation of the front page (72) Inventor Takayuki Kuwashima 1-9-9 Kakimotocho, Toyota City, Aichi Prefecture Inside Trinity Industry Co., Ltd. (56) References JP-A-4-358554 (JP, A) JP-A-52- 89146 (JP, A) Japanese Patent Publication No. Sho 45-32838 (JP, B1) Jikken Sho 50-16992 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B05B 5/00-5 / 16

Claims (3)

(57) [Claims] 1. A powder paint is applied to a rotary spray head (5) attached to a tip of the tubular rotary shaft (4) through a paint flow path inserted through a tubular rotary shaft (4) of an air motor (3). In a multicolor electrostatic coating machine for powder coating of a center feed type for supplying powder coating, a plurality of narrow nozzles (N _{1 to} N ₆ ) serving as a coating flow path for supplying powder coating to a rotary spray head (5) are provided. Elastic tubes (6) are inserted through the shaft of the tubular rotary shaft (5) in a non-contact state, and are supplied to the respective paint supply pipes (6) for supplying powder paint of each color from the paint supply source in a state of being suspended in an air flow. 7) are connected via a, the elastic tube (7) and to the fine tubular nozzle by the collapse pressure of the space inside the elastic tube by applying individually pressurized (7) from its surroundings (N ₁ to N ₆₎ closing valve for conducting or blocking the paint supply tube connected _{(6) (V 1 ~V 6} ) is in each paint passage Multicolor electrostatic coating machine for powder coatings, characterized in that eclipse the. 2. A powder paint is applied to a rotary spray head (5) attached to a tip of the tubular rotary shaft (4) through a paint flow path inserted through a tubular rotary shaft (4) of an air motor (3). in multicolor electrostatic coating machine for center feed type powder coatings supplied, a plurality of capillary-like nozzle as a paint passage for supplying powder coating rotating spray head _{(5) (N 1 ~N 5} ) is, The nozzle hole (H _{1 to} H ₅ ) is inserted in a non-contact state into the axis of the tubular rotary shaft (5), and the nozzle holes (H _{1 to} H ₅ ) are arranged annularly toward the rotary spray head (5). ₁ to H ₅₎ on the front side of the thin tube-like nozzles arranged annularly (N ₁ to N ₅₎ formed a through hole (32) or notch for opening only one nozzle hole of the fine tubular nozzle A shutter disk (33) is mounted so as to be rotatable around a rotation axis (34) disposed at the center of the annular arrangement. A multicolor electrostatic coating machine for powder coating, characterized in that it is used. 3. A powder paint is applied to a rotary spray head (5) attached to the tip of the tubular rotary shaft (4) through a paint flow path inserted through the tubular rotary shaft (4) of the air motor (3). In a multicolor electrostatic coating machine for powder coating of a center feed type for supplying powder coating, a plurality of narrow nozzles (N _{1 to} N ₆ ) serving as a coating flow path for supplying powder coating to a rotary spray head (5) are provided. Each of the thin tubular nozzles (N _{1 to} N ₆ ) is inserted into the tubular rotary shaft (5) in a non-contact state, and is provided with a paint supply source ( P _{1 to} P ₆ ) and switchably connected to a cleaning air supply source that supplies cleaning air, and at the time of coating, only one selected thin tubular nozzle is connected to the coating supply source and powder paint of any color Is supplied to the rotary spray head (5) and all other capillary nozzles are connected to the cleaning air supply. Continued has been powder coating multicolor electrostatic coating machine, wherein a washing air at a predetermined pressure adapted to be supplied to the rotary atomizing head (5).