JPH0455746B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is an electrostatic coating device that applies an electric potential to a coating material to direct the coating material toward the coating material. The present invention relates to a coating device that can reduce coating unevenness.

[Conventional technology]

Electrostatic coating involves applying electric potentials of different polarities between the coating material and the object to be coated to atomize the coating material and directing it towards the object to be coated, thereby applying the coating material to the object. A mounting device is known. There is also a coating device that can apply images onto an object by forming a base body containing a coating material so that it can be gripped and a porous tip body forming a delivery portion for the coating material.

[Problems to be solved by the invention] However, in the case of such a coating device, conventionally,
The object to be coated is placed directly on a workbench made of a conductive material, and as shown in FIG.
As a result, an air gap c is locally formed between
The object to be coated (w) cannot come into uniform contact with the workbench (a).
Therefore, the amount of paint to which the potential derived from the drawing tool d is applied differs between the contact and non-contact parts of the workpiece w and the workbench a, and the amount of paint applied is uniform to the workpiece w. There is a problem that a thick coating layer cannot be obtained. In particular, when the object w to be coated is a thin sheet, the above-mentioned tendency is remarkable, and therefore, electrostatic coating on foil or paper is extremely poor in workability.

The present invention is based on attaching a non-conductive sheet to the surface on which the workpiece is placed on the workbench, thereby significantly reducing the unevenness of coating on the workbench, increasing the efficiency of drawing work, and solving the above-mentioned problems. The purpose is to provide a coating device that can solve the problem.

[Means for solving problems]

Hereinafter, one embodiment of the means of the present invention capable of achieving the above-mentioned objects and solving the problems will be described with reference to the drawings.

In the figure, a coating device 1 of the present invention can place a drawing tool 3 having a nozzle tip 2 from which a coating material applied to a positive potential is drawn out and an object W to be coated, and the coating material can be drawn from the nozzle tip 2 by applying a non-potential. The workbench 4 is capable of atomizing the coating agent and applying it to the object W to be coated, and a sheet body 10 made of a non-conductive material is attached to the surface 4A of the workbench 4 on which the object W to be coated is placed. .

In this embodiment, the drawing tool 3 has a base body 5 consisting of a marker 14 and a holder 15, and a high-voltage device capable of applying positive and negative potentials to the base body 5, the coating agent connected to the base body by an electric cord, and the workbench 4, respectively. A voltage generator 7 is attached.

In this embodiment, the marker 14 is a felt-like cylinder having a cylindrical outer cylinder 25 made of a non-conductive material, made of synthetic resin, etc., and impregnated with a coating material D. The rear end is open and the nozzle tip 2 is attached to the front end. The impregnated body 13 is loaded therein, and a cylindrical inner cylinder 26 made of non-conductive material is inserted. The inner cylinder 26 loaded with the impregnated body 13 in this manner forms the paint reservoir 6.

A small diameter portion 27 having a threaded portion 27A on the outer surface is connected to the front end of the outer cylinder 25 via a step, and the rear end portion of the nozzle tip 2 is fitted into the small diameter portion 27 while keeping contact with the impregnating body 13. Ru.

In this example, the nozzle tip 2 is made of a porous material such as felt, into which the coating material stored in the impregnated body 13 can enter, and has a tapered conical front end.

The protector 9 has the threaded portion 27 of the small diameter portion 27.
It is a cylindrical body with open ends on its inner surface 29 having a female thread 29A that is screwed into A, and is made of a non-conductive material such as synthetic resin. Further, the front end of the protector 9 can extend beyond the tip of the nozzle tip 2 and surround the nozzle tip 2 due to the screw engagement, and the protector 9 can surround the nozzle tip 2.
can be protected.

As described above, the holder 15 includes a main part 19 having a circular cross section with its axis facing forward and backward, a short shelf-shaped neck part 20 extending forward from above the front end of the main part 19, and a neck part 20 attached to the tip of the neck part 20. and a head 22. Further, in this example, the holder 15 is integrally formed using a non-conductive synthetic resin material.

The main portion 19 is provided with a circular, shallow-bottomed recess 31 on its front end surface into which the peripheral surface of the outer cylinder 25 of the marker 14, ie, the rear end portion of the body, is fitted. Also, on the bottom of the recess 31,
A through hole 32 extending to the rear end of the main portion 19 is bored through which the needle-shaped body 17 can pass.

In this embodiment, a small diameter portion 3 is provided at the rear end of the body of the marker 14 and tightly fits into the peripheral wall of the recess 31 via a step.
By providing 0, the marker 14 can be positioned in the front-back direction.

The needle-shaped body 17 connects to the front end of the insertion piece 35 passing through the through-hole 32 a needle-shaped and long connecting piece 36 that extends forward along the axis of the recess 31 . Note that the tip of the connecting piece 36 is cut off obliquely to facilitate insertion of the marker 14 into the impregnated body 13. Further, both the insertion piece 35 and the connection piece 36 are formed using a highly conductive material such as metal.

The head 22 is a rectangular plate having a wider width than the neck 20, and a concave guide surface 37 formed in an arc centered on the extension axis of the recess 31 is provided on its lower surface. The guide surface 37 is positioned and formed at a position where the rear end of the marker 14 fits into the recess 31 and comes into contact with the other circumferential surface. Also, on the top surface of the head 22 is a mounting seat 3 on which the switch 21 is attached.
9 is provided.

As shown in FIG. 4, the high voltage generator 7 has a DC power source 43 such as a battery inside the case body 41.
a converter 45 that converts the direct current obtained by the power supply section 43 into alternating current; and a converter section 46 that can generate a pulsating direct current by boosting and converting the exchange current output from the converter 45. will be provided.

A switch S1 for turning on and off the power is interposed in the circuit between the power supply section 43 and the input side of the converter 45, and the converter 45 uses an oscillator to generate an alternating current at a frequency of 20 to 100 Hz, preferably 40 to 80 Hz. to occur. Note that when using an alternating current equal to the commercial frequency, an outside line such as a power line may be directly connected.

The converter 46 includes a transformer 47 including a primary winding for inputting the output of the converter and a secondary winding for boosting the voltage, and an intermediate tap A is provided in the secondary winding. It will be done. A DC converter is formed between the intermediate tap A and the positive terminal B by a rectifier 49 and a capacitor 50, and a boosted alternating current is obtained between the intermediate tap A and the negative terminal C. Therefore, between the positive and negative output terminals D and E of the converter 46, the fifth
A pulsating direct current as shown in the figure is generated, and in this example, the bias voltage F is set to 1 KV and the peak voltage G is set to 8 KV.

The positive output end D is connected to the holder 1 via the electric wire 52.
The negative output end E is connected to the rear end of the insertion piece 35 of No. 5, while the negative output end E is electrically connected to the workbench 4 via a switch 21 attached to the mounting seat 39 of the holder 15.

Further, by turning off the opening/closing tool S1, the loss current flowing inside the high voltage generator 7 when not in use can be cut, which helps extend the life of the generator 7. Note that the opening/closing tool S1 can also be formed to turn on and off in conjunction with the operation of a switch 21 provided on the holder 15.

The workbench 4 is a plate-shaped body made of a material having good electrical conductivity, such as gold metal or conductive rubber, and its workpiece mounting surface 4A is made of a non-conductive material and is relatively easily charged with static electricity. A sheet body made of synthetic resin, ebonite, etc. and having a thickness of 1.0 mm or less is adhered to the entire surface of the workbench 4 using an adhesive or the like.
Therefore, the entire sheet body 10 is charged to the same potential as the workbench 4, and functions as a capacitor of the potential application circuit on the negative side of the nozzle tip 2.
Furthermore, even if there is an air gap C between the object W to be coated and the sheet body 10 due to waving or the like on the object W, the sheet body 10 does not allow air to pass through the contact portion. to the same potential as the workbench 4 and to charge it evenly.

The workbench 4 can also be formed by laying metal foil such as aluminum foil on the surface of a non-conductive material such as insulating rubber, or the conductivity of the surface can be increased by applying chrome plating or the like. be.

The switch 21 extends from its negative terminal and its tip is exposed on the surface of the push button 54, so that when the operator touches the exposed end 55 when operating the switch 21, the electric potential charged by the operator leaks. sell.

The high voltage generator 7 is connected to its positive output terminal D to the holder 15 of the base 5 and its negative output terminal E to the workbench 4, and the rear end of the body of the marker 14 is connected to the holder 15 of the holder 15. By fitting into the recess 31, the needle-shaped body 17 of the holder 15 is thrust into the impregnated body of the marker 14, and a positive potential is applied to the paint stored in the marker 14 by the plunge.

Furthermore, by placing the object W to be coated on the substrate 5 and bringing the nozzle tip 2 at the tip of the substrate 5 close to the object W while gripping the substrate 5, the coating material applied to the positive potential becomes negatively charged. It is atomized and drawn out toward the base 5 in a strip and at a distant position, and the base 5 is
The coating agent can be applied to the upper object W to be coated.

[Effect]

By gripping the base 5 with the marker 14 adhered to the holder 15 and turning on the switch 21, a positive potential is applied to the paint and a negative potential is applied to the workbench 4.

Since the non-conductive sheet body 10 is provided on the workbench 4, even if there is an air gap C between the sheet body 10 and the object W to be coated, the sheet body 1
0 functions as a capacitor in the potential application circuit at the negative potential of the nozzle chip 2, and the converter 46
By softening and equalizing the peak uniform voltage of the pulsating direct current obtained by
The paint can be applied evenly to the surface without uneven coating.

[Effect of idea]

As described above, the coating device of the present invention applies a non-conductive positive voltage to the surface of the workbench on which the workpiece is placed so that the paint applied to the positive potential derived from the nozzle tip of the drawing tool can be applied to the workpiece. As a result of applying a negative potential evenly to the sheet body, a uniform coating is formed over the entire surface of the sheet body without uneven coating unlike conventional ones, and the coating quality is improved. It is possible to improve the efficiency of drawing instrument work.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention together with an example of its use, and FIG. 2 is a sectional view showing the main parts thereof.
Fig. 3 is an exploded perspective view of the same, Fig. 4 is an electric circuit diagram of the high voltage generator, Fig. 5 is a graph showing the waveform of the output voltage of the output generator of the high voltage generator, and Fig. 6 shows the operation. Front view, FIG. 7 is a front view showing the prior art. 2... Nozzle tip, 3... Drawing tool, 4... Workbench,
4A... object placement surface, 10... sheet body, W... object to be coated.

Claims (1)

[Claims] 1. A drawing tool having a nozzle tip from which a paint applied to a positive potential is drawn out, and an object to be coated is placed thereon, and a negative potential is applied to atomize the paint from the nozzle tip at a distant position. A coating apparatus comprising a workbench capable of coating the object to be coated, characterized in that a sheet body made of a non-conductive material is attached to the surface of the workbench on which the object to be coated is placed. Device.