JPS6012090B2 - electrostatic painting gun - Google Patents

Description

[Detailed description of the invention] The present invention relates to electrostatic painting guns.

In conventionally known electrostatic coating methods and coating guns for powder coatings, one or more common electrodes charge the powder coating and form an electric field between objects to be coated.

For this reason, it is not possible to individually control the amount of charge on the powder coating material and the strength of the electric field formed. On the other hand, from the viewpoint of powder coating efficiency, the voltage applied to the charging electrode is often increased to increase the amount of charge, but as the charging voltage increases, the strength of the tortoise field increases, making it difficult for the powder coating to penetrate into narrow gaps. At the same time, high voltage is applied to the electric field forming electrode, which impairs the safety of the working environment. Further, in order to increase the thickness of the coated surface of the object to be coated, the voltage applied to the electric field forming electrode is lowered, but as the electric field strength decreases, the voltage applied to the charging electrode also decreases, resulting in a decrease in coating efficiency. In order to solve the above-mentioned problem, the present applicant first charges the powder coating material with a charging electrode while controlling its transport, and then ejects the charged powder coating material to form an electric field between it and the object to be coated. An electrostatic coating method for a powder coating that controls the adhesion of ejected charged powder coating to an object to be coated by the electric field strength formed by an electrode, and a powder coating having an electrode for charging the powder coating inside the gun body. This is an electrostatic coating gun for powder paint, in which a conveyance path is formed, and a nozzle cap for ejecting charged powder paint is attached to the tip of the conveyance path. I proposed (Mochikao 52-089285
issue).

The present invention aims to improve the above-mentioned electrostatic coating method for powder paint and the coating gun, and the purpose of the present invention is to provide a powder paint conveying passage at the tip of the gun body, which has a powder paint conveying passage formed therein, and a spray jet that is connected to the conveying passage. Install the nozzle cap with an outlet,
An electric field forming electrode for forming an electric field between the nozzle cap and the object to be coated is arranged, and powder paint charging electrodes are arranged in multiple stages along the conveyance path, and the charging at each stage is arranged in multiple stages. An electrostatic coating gun is provided in which the electrode for forming an electric field is made up of at least two electrodes having different voltages, and the voltage of the electrode for forming an electric field is easily controlled for adhering powder coating to an object to be coated. Ru.

A first embodiment of the present invention will be described below with reference to the attached FIGS. 1 and 2.

In FIG. 1, a gun body 1 has one end connected to a powder storage tank and a compressed air source (both not shown) for compressed air transport of the powder paint stored in the storage tank, and has a powder paint transport passage la inside. have A nozzle cap 3 is attached to the tip of the nozzle body 1 using a nozzle cap cover 2. The nozzle cap 3 has a spout 3a that fits into the powder coating conveyance path la. Note that a nozzle cap stand 4 is fixed to the rear end of the nozzle cap 3, and the nozzle cap stand 4 is pressed and fixed by a nozzle cap cover 2. Two sets of charging electrodes 5 and 6 are provided along the powder paint transport path la.
The charging electrodes 5 and 6 each consist of four terminal electrodes 7 and 8. Each set of terminal electrodes 7, 8 is arranged laterally in the powder coating passage la, that is, on a plane perpendicular to the flow direction. The terminal electrode 7 is connected to a high voltage terminal of the high voltage generator 11 via a high voltage IJ-wire 9, and the terminal electrode 8 is connected to a relatively low voltage terminal of the high voltage generator 11 via a low voltage lead wire 10. Connect to. Also, the second high voltage generator 1
2 is connected to the electric field forming electrode 15 via the electric field forming electrode lead wire 13 and the electric field forming electrode resistor 14. The high voltage generators 11, 12 are connected to a power supply 19 via a switch 16 and a supply voltage regulator 17, 18. The object 20 to be painted is installed, the nozzle cap 3 of the painting gun shown in FIGS. 1 and 2 is directed toward the object 20, and the switch 16 is turned on.

Powder paint is transported from a storage tank (not shown) through a powder paint transport path la by a predetermined pneumatic pressure at a speed determined by the size of the transport path la. Powder paint is conveyed through the conveyance path l.
Charging electrodes 5 and 6 provided in two stages along line a are repeatedly charged with high voltage and relatively low high voltage by terminal electrodes 7 and 8 connected to high voltage generator 11, and are sufficiently charged. . The high-voltage fog poles T of each set (each stage) have the same magnetism, so that the powder paint that is not charged by the first stage electrode 5 can be charged by the second stage electrode 6.
Moreover, the charge in the first stage is not discharged in the second stage, and the charging efficiency is improved. Then, the powder coating material is ejected from the ejection port 3a of the spray cap 3. On the other hand, an electric field forming electrode 15 provided on the nozzle cap 3 is connected to a high voltage generator 12 via a resistor 14 to form an electric field with the object 20 to be coated. Therefore, the powder coating material ejected from the ejection port 3a of the nozzle cap 3 is controlled by the electric field and adheres to the object to be coated 20'. In the electrostatic painting gun shown in FIGS. 1 and 2, the voltages applied to the charging electrodes 5 and 6 provided in two stages can be adjusted simultaneously by changing the settings of the supply voltage regulator 17, and the The voltage applied to the electrode 15 can be adjusted independently of the charging electrodes 5 and 6 by changing the settings of the supply voltage regulator 18.

While controlling the transport of the powder paint, the charged paint is charged in multiple stages using charging electrodes provided in multiple stages to sufficiently increase the charging efficiency, and then the charged paint is transferred to the object to be coated using an electric field of arbitrary strength formed by an electric field forming electrode. It can be applied to many areas, and a sufficiently high application efficiency can be obtained.

The first embodiment allows the charging of the paint and the strength of the electric field to be adjusted independently according to the shape and quality of the object to be painted, and is particularly effective as a handgun-type painting gun for manual painting and a painting method using the same.

Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment differs from the first embodiment in the high voltage application circuit.
That is, the electric field forming lead wire 13 connected to the electric field forming electrode 15 is connected to the low voltage lead wire 101 continuous to the terminal electrode 8 of the charging electrodes 5 and 6, and the high voltage generating device 12
(Fig. 1) and the supply voltage regulator 18 (Fig. 1) are omitted. Therefore, in the second embodiment shown in FIG. 3, a high voltage of a predetermined ratio can be applied to the charging electrodes 5, 6 and the electric field forming electrode 201 via the high voltage generator 11 by the supply voltage regulator 17. Suitable as an automatic gun for painting large quantities of objects to be painted, and as a painting method using it.

A third embodiment will be described with reference to FIG.

In the first embodiment shown in FIGS. I and 2, the charging electrodes 5 and 6 are connected to one high voltage generator 11.
In the third embodiment shown in FIG. 4, charging electrodes 5 and 6 are connected to different high voltage generators 11 and 11' via lead wires 9 and 9' and 10 and 10', respectively. 11, 11' are respectively connected to different supply voltage regulators 17,
Connected to 17'. By setting the supply voltage regulators 17, 17', predetermined voltages can be applied to the terminal electrodes 7, 8 and 7', 8' of the charging electrodes 5, 6, respectively. For example, by applying a rather low voltage to the first-stage charging electrode 5 located on the upstream side, and applying an extremely high voltage to the second-stage charging electrode 6, charging efficiency can be further improved.
Also, depending on the shape of the object to be coated and the set film thickness, the charging electrodes 5 and 6
Also, the voltage applied to the electric field forming electrode 15 can be adjusted independently as appropriate, and the coating efficiency can be increased. In the present invention, the charging electrode may be arranged in three or more stages.

However, in the present invention, since the powder coating is charged in multiple stages, good charging efficiency can be obtained with a relatively low voltage, and the charged powder coating can be controlled by the electric field strength l formed by the electric field forming electrode. Since it adheres to the object while being coated, the coating efficiency is increased and good coating is obtained. Furthermore, by applying the optimum voltage to each electrode, there is no need to use an excessively high voltage, which improves safety. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of the device according to the first embodiment of the present invention, and FIG.
FIG. 3 is an electrical circuit diagram of the device shown in the figure, FIG. 3 is an electrical circuit diagram of a second embodiment of the present invention, and FIG. 4 is an electrical circuit diagram of a third embodiment of the present invention.

1...Gun body, la...Powder paint conveyance passage,
5, 6... Charging electrode, 7, 7', 8, 8'.
...Terminal electrode, 11, 11', 12...High voltage generation diamond, 15...Electrode for forming electric field, 20...Object to be painted.

Figure 1 Figure 2 ・ Figure 3 Figure 4

Claims (1)

[Claims] 1. A nozzle cap having a spout communicating with the conveyance passage is attached to the tip of the gun body in which the powder paint conveyance passage is formed, and the nozzle cap has a nozzle cap for forming an electric field between it and the object to be coated. Further, powder paint charging electrodes are arranged in multiple stages along the conveyance path, and the charging electrodes in each stage are arranged horizontally in the conveyance path and have at least two different voltages. An electrostatic coating gun characterized in that the high voltage side electrodes of each stage have the same polarity as each other and the electric field forming electrode.