JP2006007129A - Spray gun for electrostatic painting - Google Patents

Abstract

Disclosed is a compact air spray type spray gun for electrostatic coating suitable for electrostatic coating using a paint having low electrical resistance.
A paint nozzle (30) made of an insulating material having a paint discharge port (32) at the tip is attached to the front end of a barrel (2) whose front part is formed in a substantially cylindrical shape. A cylinder that covers the front end face of the paint nozzle and the barrel, and also serves as an atomizing air outlet (33) through which a paint discharge port is inserted in the center and jets compressed air that atomizes the paint discharged from the paint discharge port An air cap (50) made of an insulating material to which the electrode (55) is attached is attached. A pin electrode (35) protruding forward from the paint discharge port is attached, the pin electrode is grounded, and a DC high voltage is applied between the pin electrode and the cylindrical electrode.
[Selection] Figure 2

Description

  The present invention relates to a spray gun for electrostatic coating, and more particularly to a spray gun for electrostatic coating suitable for electrostatic coating using a water-based paint or metallic paint having a relatively low electrical resistance.

  In general, paints used for electrostatic coating of car bodies and the like are solvent-based paints (oil-based paints) having a relatively high electrical resistance, water-based paints (water-based paints) having a relatively low electrical resistance, and metal powder dispersed therein. And metallic paints. When electrostatic coating is performed using water-based paints or metallic paints with relatively low electrical resistance, a high voltage is applied directly to the charging electrode of the electrostatic coating gun body that comes into contact with these paints. The current flows to the grounded paint tank through the path. For this reason, since a high voltage cannot be applied between the charging electrode and the object to be coated, no discharge occurs and the atomized paint particles cannot be charged.

  As a conventional technique for solving this problem, for example, there is a method of electrically insulating the paint tank from the ground. According to this method, since a high voltage can be applied between the charging electrode of the electrostatic coating gun body and the object to be coated, the paint particles can be charged. However, a special paint replenishing device that interrupts the painting operation when replenishing the paint to apply a high voltage to the paint tank or replenishes the paint tank while maintaining electrical insulation (for example, Patent Documents) 1)).

  As another solution, there is a system called an external electrode system in which one or a plurality of external electrodes are arranged at positions radially outside the electrostatic coating gun body and a high voltage is applied thereto. This method includes a method using a rotary atomizing head for atomizing paint in the electrostatic coating gun body (for example, see Patent Document 2) and an air spray method using compressed air (for example, see Patent Document 3). is there. In both systems, the external electrode to which a high voltage is applied does not come into contact with the paint having a low electrical resistance, so that the paint particles can be charged while the paint tank is grounded. Therefore, continuous coating is possible without requiring a special device for replenishing the paint tank with the paint. However, in the case of the external electrode method, the external electrode is attached to the outside of the electrostatic coating gun main body, so that the electrostatic coating gun becomes large and there is a high risk because an electrode to which a high voltage is applied exists outside the main body. . There is also a problem that the atomized paint particles easily adhere to the vicinity of the external electrode or around the electrostatic coating gun body due to electrostatic force.

In order to avoid such problems of the external electrode type, the inventors of the present application have a pin electrode protruding from the paint discharge port at the tip of the electrostatic coating gun, and an inner side of the air cap attached to the front end surface of the electrostatic coating gun. Has developed an air spray electrostatic coating gun (see Patent Documents 4 and 5) that charges a paint by applying a high voltage between electrodes housed in the pattern air flow path. .
JP 2002-143730 A Japanese Patent Laid-Open No. 06-134353 Japanese Patent Laid-Open No. 09-136047 Japanese Patent Application No. 2003-87882 Japanese Patent Application No. 2003-399464

  The present invention has been made from such a background, and the subject thereof is an air spray type electrostatic coating gun that can be used for electrostatic coating using a water-based paint or metallic paint having a relatively low electrical resistance. An object of the present invention is to provide a spray gun for electrostatic coating having a compact structure in which a paint tank can be grounded and coated, and no electrode is provided outside the main body.

  The invention described in claim 1 for achieving the above object is a spray gun (1) for electrostatic coating in which a paint atomized with compressed air is charged using a high voltage and applied to an object to be coated. A barrel (2) having a front part formed in a substantially cylindrical shape, a paint nozzle (30) made of an insulating material having a paint discharge port (32) attached to the front end of the barrel, and the paint nozzle An atomizing air outlet (33) for covering the front end surface of the barrel and for inserting compressed paint for atomizing the paint discharged through the paint discharge port at the center portion. An air cap (50) made of an insulating material to which a cylindrical electrode (55) serving also as an electrode is attached, and a pin electrode (35) protruding from the paint discharge port, are grounded to the cylindrical electrode. It is characterized by applying DC high voltage. It is a spray gun for electrostatic coating.

  According to the spray gun for electrostatic coating having such a configuration, electrostatic coating using a paint having low electrical resistance can be performed. In addition, according to this configuration, since the cylindrical electrode to which a high voltage is applied is attached near the center of the air cap that covers the tip of the paint nozzle and the barrel, the external electrode type that attaches the electrode to the outside of the barrel There is an advantage that the device is smaller than the gun of this type.

  The invention according to claim 2 is a pattern air flow path for supplying compressed air between the inner surface of the air cap and the outer peripheral surface of the paint nozzle in the spray gun for electrostatic coating according to claim 1. (54) and a pair of pattern air ejection holes (61) that project forward from the left and right ends of the air cap and communicate with the pattern air flow path to eject compressed air obliquely inward and forward. A corner portion (60) is provided.

  The pattern air ejected by such a configuration has the effect of forming an atomized pattern of atomized paint particles into an oval or oval shape suitable for painting. In addition, the pattern air functions to convey charged paint particles to the vicinity of the object to be coated, and at the same time, has the effect of reducing the paint particles adhering to the air cap surface.

  According to a third aspect of the present invention, there is provided the spray gun for electrostatic coating according to the first or second aspect, wherein the paint nozzle supplies the compressed air for atomizing the paint. And a plurality of sub-atomizing air ejection holes (56) that communicate with the atomizing air flow path and eject compressed air in the air cap portion outside the cylindrical electrode (55). It is characterized by that.

  With such a configuration, the compressed air ejected from the sub-atomizing air ejection holes helps to atomize the paint, and at the same time has an effect of preventing charged paint particles from adhering to the air cap surface and the cylindrical electrode.

According to a fourth aspect of the present invention, in the spray gun for electrostatic coating according to any one of the first to third aspects, power is supplied to the cylindrical electrode (55) from the front portion of the barrel (2). And a conductor wire (65) extending from the high voltage supply terminal (13) provided in the air cap to the cylindrical electrode through the air cap.
According to such a configuration, there is an effect that the conductor wire to which the high voltage is applied passes through the air cap, and thus safety is increased and at the same time, it is stably held.

According to a fifth aspect of the present invention, in the spray gun for electrostatic coating according to any one of the first to fourth aspects, the pin electrode (35) is grounded using the conductivity of the paint. It is characterized by that.
With such a configuration, there is an effect that a ground line from the pin electrode to the ground is not required.

According to a sixth aspect of the present invention, in the spray gun for electrostatic coating according to any one of the first to fourth aspects, the pin electrode (35) is grounded via a ground wire. And
With such a configuration, there is an effect that electrostatic coating using a paint having no conductivity is possible.

According to a seventh aspect of the present invention, in the spray gun for electrostatic coating according to any one of the first to fourth aspects, the pin electrode (35) is eliminated, and the paint discharged from the paint discharge port (32) is used. Is characterized in that it is grounded using the conductivity of the paint.
Even in such a configuration, the atomized paint is charged. Therefore, the same effect as that of the first aspect of the invention can be obtained.

(First embodiment)
Hereinafter, a first embodiment of a spray gun for electrostatic coating according to the present invention (hereinafter simply referred to as a spray gun) will be described with reference to FIGS. The spray gun 1 of the present embodiment is mainly intended to use a water-based paint or a metallic paint having a low electrical resistance as a paint. FIG. 1 is a longitudinal sectional view of the entire structure of the spray gun 1 of the present embodiment, FIG. 2 is a longitudinal sectional view of the tip portion thereof, and FIG. 3 is an enlarged longitudinal sectional view in the vicinity of the pin electrode 35 at the tip, paint and compressed air. FIG. 4 is a perspective view of the tip air cap 50, and FIG. 5 is a perspective view showing the positional relationship of the electrodes.

  The spray gun 1 includes a barrel (barrel) 2 which is a gun body and a grip 3 provided at the rear end thereof. The barrel 2 is made of an insulating synthetic resin material and has a substantially cylindrical shape as a whole. This spray gun 1 is a spray gun with a built-in high voltage generation circuit, and a cascade 4 that is long in the front-rear direction is integrally formed with a step-up transformer and a high voltage rectifier circuit that are necessary for generating a high voltage in the upper part of the barrel 2. It is stored. The high frequency voltage as the power is taken in from the power connector 5 attached to the lower part of the grip 3 and supplied to the step-up transformer in the cascade 4 through a wiring cable (not shown) in the grip 3. The supplied high frequency voltage is boosted by a step-up transformer, and is boosted simultaneously with rectification by a high voltage rectifier circuit using a Cockcroft-Walton type voltage doubler rectifier circuit to generate a DC high voltage of several thousand to several tens of thousands of volts.

  The generated DC high voltage is a cylindrical conductive contact that is screwed into a hole formed in the barrel 2 at the front portion of the cascade 4 through the output spring 6 at the front end of the cascade 4 and a conductive spring 7 that is in contact therewith. 8 is led to the rear end side. Then, it is taken out from the front end side of the contact 8 by another conductive spring 9. A cylindrical resistance holding body 10 is attached to the front end side of the spring 9 by screwing into a hole drilled from the front end surface of the barrel 2. The spring 9 has a front end portion inserted in a hole drilled on the rear end side thereof, and urges the high resistance body 11 inserted in the hole toward the back end portion, and at the same time, applies a high voltage to the rear end terminal of the high resistance body 11. Lead. The front end terminal of the high resistance body 11 is in contact with the conductor rod 12 penetrating the resistance holding body 10 from the back end portion of the hole. The leading end side of the conductor rod 12 is connected to a high voltage supply terminal 13 attached to the front end of the resistance holder 10. The high voltage generated in this way is supplied to the high voltage supply terminal 13 through the high resistor 11 for current limitation.

  The paint is supplied from a paint tank (not shown) to a paint hose joint 15 attached to the lower part of the grip 3 by a paint hose (not shown). From there, it is guided to the valve chamber 21 of the paint valve 20 through the paint tube 16. The paint valve 20 is provided in a guide hole 23 that is drilled from the center of the rear end of the mounting recess 22 provided in the center of the front end of the barrel 2 toward the rear end of the barrel 2. The paint valve 20 includes a valve chamber 21, a needle 24, a guide hole 23, a valve port 25, and a packing 26. The needle 24 has a tapered front end and penetrates the valve chamber 21 in the front-rear direction. The guide hole 23 guides a portion of the needle 24 behind the valve chamber 21 so as to be movable in the front-rear direction. The valve port 25 communicates between a later-described paint nozzle 30 fixed to the front end of the paint valve 20 and the valve chamber 21 and is opened and closed by contacting and separating the tapered front end portion of the needle 24. . The packing 26 is mounted between the valve chamber 21 and the guide hole 23 and is in close contact with the outer periphery of the needle 24 in a liquid-tight state.

  The needle 24 in the paint valve 20 is always held in a closed state in which the valve port 25 is closed by the urging of the return spring 69 provided at the rear end of the barrel 2, and the supplied paint is applied to the paint nozzle 30. Discharging is blocked. The needle 24 moves backward against the return spring 69 only while the trigger 68 is pulled, the valve port 25 is opened, and the paint valve 20 is opened. When the paint valve 20 is opened, the paint supplied into the valve chamber 21 is discharged into a paint nozzle 30 attached in front of the paint valve 20.

A mounting recess 22 having a circular cross section is formed at the front end of the barrel 2 in the form of a notch at the center of the front end surface. A paint nozzle 30 made of an insulating synthetic resin material is provided on the inner periphery of the mounting recess 22 at the rear end. And the front end is fixed in a form protruding forward from the mounting recess 22.
A central hole that penetrates between both front and rear end faces of the paint nozzle 30 communicates with the valve port 25 as a paint flow path 31. A front end of the paint nozzle 30, that is, a portion corresponding to the front end of the paint flow path 31 is formed so as to protrude to a small diameter, and is inserted as a paint discharge port 32 in an open state from an atomizing air outlet 33 of an air cap 50 described later. . The paint supplied from the paint valve 20 passes through the paint flow path 31 and is discharged forward from the paint discharge port 32.

  A pin electrode 35 thinner than the inner diameter of the paint discharge port 32 protrudes forward and is inserted. The rear end side of the pin electrode 35 is formed as a coiled spring and is accommodated in the paint flow path 31, and the pin electrode 35 is held in a state of protruding forward by the bias of the spring. In this embodiment, a water-based paint or a metallic paint having a relatively low electrical resistance is used as the paint. The pin electrode 35 is electrically connected to a grounded paint tank (not shown) by the conductivity of the paint and is maintained at the ground potential.

  In the paint nozzle 30, a plurality of atomizing air flow paths 36 concentrically arranged with the paint flow path 31 are formed in a hole shape penetrating between both front and rear end faces of the paint nozzle 30. The front end of the atomizing air channel 36 communicates with an annular atomizing air channel 37 surrounded by the front end surface of the paint nozzle 30 and the back surface of the air cap 50.

  The front end of the paint nozzle 30 is covered with an air cap 50. The outer peripheral portion of the front end of the paint nozzle 30 protrudes in a large-diameter annular shape toward the front end side, and the annular protrusion 38 is fitted with a recessed portion 51 on the inner surface of the air cap 50. In this state, the air cap 50 is fixed in a state where it is pressed against the paint nozzle 30 by a retaining nut 53 that is screwed to the outer peripheral surface of the cylindrical portion 52 formed to protrude forward from the outer peripheral edge of the front end of the barrel 2. . As a result, an annular gap surrounded by the inner surface of the air cap 50, the outer peripheral surface of the paint nozzle 30, the inner peripheral surface of the cylindrical portion 52, and the front end surface of the barrel 2 is formed. This gap is used as the pattern air channel 54.

  A cylindrical electrode 55 is fitted in the central portion of the air cap 50 so as to form an atomizing air ejection port 33. That is, as shown in FIG. 3, the cylindrical electrode 55 is fitted in the center portion of the air cap 50, and the inside thereof is the atomizing air ejection port 33. A small-diameter paint discharge port 32 formed at the tip of the above-described paint nozzle 30 is inserted into the atomizing air outlet 33, and a pin electrode 35 protrudes forward through the paint discharge port 32. Yes. The atomizing air ejection port 33 communicates with the annular atomizing air flow path 37 and ejects compressed air supplied through the atomizing air flow path 36 forward.

Further, a plurality of sub-atomizing air ejection holes 56 communicating with the annular atomizing air flow path 37 are formed in the outer portion of the cylindrical electrode 55, and the compression supplied from the atomizing air flow path 36 is performed. Air is ejected diagonally inward and forward.
As shown in the perspective view showing the positional relationship of the electrodes in FIG. 5, the cylindrical electrode 55 is connected to the high voltage supply terminal 13 provided on the front surface portion of the resistance holding body 10 by a conductor wire 65 passing through the inside of the air cap 50. It is connected. That is, a DC high voltage generated by the high voltage generation circuit is applied to the cylindrical electrode 55.

Further, a pair of corner portions 60 that are opposed to each other in the left-right direction and project forward are formed from both ends of the surface of the air cap 50. Each corner 60 is formed with a plurality of pattern air ejection holes 61 (two on the left and right in FIGS. 2 and 4) communicating with the pattern air flow path 54. Erupt towards.
Atomized air and compressed air for pattern air are supplied from a compressed air generator (not shown) to an air hose joint 71 attached to the lower part of the grip 3 by a high-pressure air hose. From here, the compressed air passes through an air flow path 72 in the grip 3 and is guided to an air valve 73 provided at the rear end of the barrel 2.

  The air valve 73 opens and closes compressed air supplied by a valve body 74 that moves back and forth integrally with the needle 24. When the paint valve 20 is opened, the air valve 73 is also opened, and when the paint valve 20 is closed, the air valve 73 is also closed. When the air valve 73 is opened, the compressed air passes through the atomizing air supply passage 75 and the pattern air supply passage 76 provided in the barrel 2, respectively, and the annular atomizing air passage 77 at the rear end of the paint nozzle 30 and the annular air passage 73. It is supplied to the pattern air channel 54. An annular atomizing air channel 77 communicates with the atomizing air channel 36 to supply atomizing air.

  Next, the operation of the spray gun 1 of the present embodiment configured as described above will be described. When the trigger 68 is pulled, the paint valve 20 is opened, and the paint supplied from the paint hose joint 15 is discharged to the paint flow path 31, and is transmitted from the paint discharge port 32 at the front end of the paint nozzle 30 to the surface of the pin electrode 35. And discharged in the form of a film. At the same time, a high-frequency voltage is supplied to the high-voltage generating circuit in the cascade 4, and a DC high voltage of several thousand to several tens of thousands of volts generated by the high-voltage rectifier circuit is applied to the high resistor 11, the conductor rod 12, the high voltage supply terminal 13, and the conductor. It is supplied to the cylindrical electrode 55 via a line 65.

Since the pin electrode 35 is grounded using the conductivity of the paint, a strong electric field is generated from the surface of the pin electrode 35 toward the cylindrical electrode 55 to which a high voltage is applied. As a result, a large amount of charge having a polarity opposite to the polarity of the high voltage of the cylindrical electrode 55 is induced on the surface of the conductive coating material that travels on the surface of the pin electrode 35.
Further, simultaneously with the trigger 68 being pulled, the compressed air that has passed through the atomizing air flow path 75 is jetted forward through the atomizing air outlet 33. The atomized air collides with the paint traveling on the surface of the pin electrode 35 and atomizes the paint by the principle of spraying. Simultaneously with the ejection of the atomized air, the compressed air supplied from the atomized air passage 36 is also ejected from the sub-atomized air ejection hole 56. This compressed air also plays an auxiliary role in the atomization of the paint.

The paint particles atomized in this way jump out into the air with the electric charge induced when they are in contact with the surface of the pin electrode 35. That is, the atomized paint particles are charged with a polarity opposite to the polarity of the cylindrical electrode 55.
On the other hand, the compressed air supplied to the pattern air flow path 54 is ejected vigorously from the pattern air ejection holes 61 provided in the left and right corner portions 60 as the pattern air toward the diagonally inner front. This pattern air forms an atomized pattern of atomized paint particles into an oval or oval shape suitable for painting. Note that the compressed air ejected from the sub-atomization air ejection holes 56 also plays an auxiliary role in forming this spray pattern.

  The paint particles are conveyed to the vicinity of the object to be coated mainly by the pattern air and the atomizing air. When the charged paint particles approach the object to be coated, a charge having a polarity opposite to the charge of the paint particles is induced on the surface of the object to be grounded by electrostatic induction. Then, an electrostatic force acts between the induced opposite polarity charge and the charged paint particles, and the paint particles receive an attractive force toward the object to be coated. The paint particles are applied to the surface of the object by both the suction force and the spray force of the pattern air and atomizing air. Since the suction force due to electrostatic force works, the paint particles also wrap around the back side of the object to be coated, and the paint is also applied to the back side of the object not facing the spray gun 1. Electrostatic coating is performed on the object to be coated by the above operation.

  In the case of the present embodiment, electric field lines concentrate on the tip of the pin electrode 35 and a high electric field is generated, so that discharge may occur at the tip of the pin electrode 35. When this discharge occurs, an ionization zone is formed in the vicinity of the tip of the pin electrode 35, so that the atomized paint particles receive charges from the ionization zone and the charge amount and polarity change. Since both charging by electrostatic induction and charging by ions formed by discharging are related, the charging mechanism of the atomized paint particles is very complicated. In any case, since the pattern air ejected from the pattern air ejection hole 61 is quite strong, the atomized paint particles are conveyed to the vicinity of the object to be coated mainly by the conveying force of the pattern air. Then, the material is applied to the object by both the suction force by the electrostatic force and the spray force by the pattern air.

  Thus, according to the spray gun 1 of this embodiment, electrostatic coating using a paint with low electrical resistance can be performed. Moreover, in the spray gun 1 of the present embodiment, the cylindrical electrode 55 to which a high voltage is applied is attached in the vicinity of the center of the air cap 50 that covers the coating nozzle 30 and the tip of the barrel 2. There is an advantage that the apparatus is smaller than an external electrode type gun in which an electrode is attached to the outside. Further, since the distance between the cylindrical electrode 55 to which a high voltage is applied and the pin electrode 35 grounded is narrow, a strong electric field can be generated at a relatively low voltage. Most of the electric lines of force of the generated electric field exist between the cylindrical electrode 55 and the pin electrode 35, and there are few electric lines of force passing through the air cap 50 made of an insulating material. Therefore, polarization of the insulating material causes less polarization charge on the surface of the air cap 50. In addition, since the pattern air transports the paint particles forward, the charged paint particles are applied to the surface of the air cap 50. Less adherence. Further, since the atomized air is ejected forward from the inside of the cylindrical electrode 55 and the sub-atomized air is ejected obliquely inward and forward from the sub-atomized air ejection hole 56 on the outside thereof, the charged paint Particles are less likely to adhere to the surface of the cylindrical electrode 55.

(Second Embodiment)
FIG. 6 is a longitudinal sectional view of the tip portion of the spray gun 1a according to the second embodiment. The configuration of this embodiment is different from that of the first embodiment only in that the pin electrode 35 is not provided. Generally, many lines of electric force are generated from a sharp part and a thin part, and the electric field strength in the vicinity thereof becomes strong. In this respect, it is preferable that the thin pin electrode 35 protrudes forward from the paint discharge port 32. However, even if there is no such pin electrode 35, the coating itself has conductivity and is maintained at the ground potential, so that the coating can be atomized in a charged state by electrostatic induction. Therefore, electrostatic coating can be performed in the same manner as in the first embodiment, and the same effect as in the first embodiment can be obtained.

(Modified embodiment)
In the embodiments so far, the paint in the pin electrode 35 or the paint nozzle 30 is grounded by utilizing the conductivity of the paint, but instead, a ground line connecting the inside of the pin electrode 35 or the paint nozzle 30 and the ground is provided. It may be provided and grounded. By doing so, electrostatic coating using a paint having no conductivity or a paint having low conductivity is also possible.

It is a longitudinal section of the whole spray gun structure concerning a 1st embodiment. It is a longitudinal cross-sectional view of the front-end | tip part of the spray gun which concerns on 1st Embodiment. It is a figure explaining the flow of the enlarged vertical cross section of the spray gun front-end | tip part which concerns on 1st Embodiment, a coating material, and compressed air. It is a perspective view of the tip air cap concerning the 1st and 2nd embodiment. It is a perspective view showing the positional relationship of the electrode which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the front-end | tip part of the spray gun which concerns on 2nd Embodiment.

Explanation of symbols

  In the drawings, 1, 1a is a spray gun for electrostatic coating, 2 is a barrel, 13 is a high voltage supply terminal, 20 is a paint valve, 30 is a paint nozzle, 31 is a paint flow path, 32 is a paint discharge port, and 33 is a mist , 35 is a pin electrode, 36 is an atomizing air channel, 50 is an air cap, 54 is a pattern air channel, 55 is a cylindrical electrode, 56 is a sub-atomizing air ejection hole, 60 is a corner, Reference numeral 61 denotes a pattern air ejection hole, and 65 denotes a conductor wire.

Claims (7)

An electrostatic coating spray gun (1) for charging a paint atomized with compressed air using a high voltage and applying it to a workpiece,
A barrel (2) whose front part is formed in a substantially cylindrical shape;
A paint nozzle (30) made of an insulating material attached to the front end of the barrel and having a paint discharge port (32) at the tip;
An atomizing air outlet (covering the paint nozzle and the front end surface of the barrel, and allowing the paint discharge port to be inserted in the center and jetting compressed air to atomize the paint discharged through the paint discharge port ( 33) an air cap (50) made of an insulating material to which a cylindrical electrode (55) that also serves as 33) is attached;
A pin electrode (35) protruding from the paint discharge port,
A spray gun for electrostatic coating, wherein the pin electrode is grounded and a high DC voltage is applied to the cylindrical electrode.   A pattern air flow path (54) for supplying compressed air is formed between the inner surface of the air cap and the outer peripheral surface of the paint nozzle, and protrudes forward from the left and right ends of the air cap to the pattern air flow path. The spray gun for electrostatic coating according to claim 1, further comprising a pair of corners (60) provided with pattern air ejection holes (61) for communicating and ejecting compressed air obliquely inward and forward. .   The paint nozzle has an atomizing air flow path (36) for supplying the compressed air for atomizing the paint inside, and the atomizing air flow path is provided in the air cap portion outside the cylindrical electrode (55). The spray gun for electrostatic coating according to claim 1 or 2, further comprising a plurality of sub-atomizing air ejection holes (56) that are communicated with each other to eject compressed air obliquely inward and forward.   Electric power is supplied to the cylindrical electrode (55) from a high voltage supply terminal (13) provided on the front surface of the barrel (2) to a conductor wire (65) passing through the inside of the air cap to the cylindrical electrode. The spray gun for electrostatic coating according to any one of claims 1 to 3, wherein the spray gun is used.   The spray gun for electrostatic coating according to any one of claims 1 to 4, wherein the pin electrode (35) is grounded by utilizing conductivity of a paint.   The spray gun for electrostatic coating according to any one of claims 1 to 4, wherein the pin electrode (35) is grounded via a ground wire. The pin electrode (35) is eliminated, and the paint discharged from the paint discharge port (32) is grounded using the conductivity of the paint. A spray gun for electrostatic coating as described in Crab.

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