JP2019058862A - Electrostatic spray method and electrostatic spray device of the same - Google Patents

Abstract

To provide an electrostatic spray method and an electrostatic spray device of the same capable of easily expanding a liquid spray range corresponding to the variation of the coating range of a coating object with a liquid.SOLUTION: An electrostatic spray method applying a voltage between a liquid spray part having the nozzle of an electrostatic spray device and a coating object, generating an electrostatic force and spraying a liquid toward the coating object from the nozzle only with the electrostatic force includes a spray step disposing a pattern expansion electrode having the same electric potential as the coating object and expanding the spray pattern of the liquid sprayed from the nozzle. The spray step is performed by disposing the pattern expansion electrode at a position being out of the existing range of the liquid sprayed when the liquid is sprayed toward the coating object without using the pattern expansion electrode and a position near the coating object between the nozzle and the coating object.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic spray method and an electrostatic spray device therefor.

  According to Patent Document 1, a voltage is applied between a liquid spray unit having a nozzle and a different pole unit which is a different pole to the liquid spray unit and the liquid spray unit, and the liquid is separated from the tip of the nozzle in a charged state. The equipotential is provided with voltage applying means for generating electrostatic force, and an equipotential line adjusting electrode made of a conductive material for adjusting the state of the equipotential curve appearing to surround the nozzle by applying the voltage by the voltage applying means. The line control electrode is at least one of the equipotential curves with respect to the state of an equipotential curve on a plane including the central axis of the nozzle which appears near the front side of the nozzle when the equipotential line control electrode is not disposed. The equipotential line control electrode is disposed near the outer periphery of the tip of the nozzle, which can be in the state of an equipotential curve that draws a gentle curve. Can Together are adapted, electrostatic spraying device which is characterized in that the equipotential lines adjusted electrodes are liquid spray section and the same potential is disclosed.

  And, since the equipotential line adjustment electrode which is set to the same potential as the liquid spray portion is disposed in the vicinity of the outer periphery of the tip of the nozzle which can be in the state of an equipotential curve that draws a gentle curve, for example, The cross-sectional area of the liquid to be sprayed can be increased or decreased, and the cross-sectional shape of the liquid to be sprayed can be a circular pattern or an elliptical pattern.

JP, 2017-87124, A

  By the way, depending on the object to be coated, there are cases where it is desired to partially increase the range of application of the liquid. Since the state of the spray range of the liquid is substantially determined, it is difficult to change the spray range of the liquid so as to follow the change in the partial application range without interrupting the spraying operation.

  The present invention has been made in view of such circumstances, and according to a change in a range to which a liquid of a material to be coated is desired to be applied, an electrostatic spray method capable of easily expanding a spray range of a liquid It is an object of the present invention to provide an electrostatic spray device.

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) In the electrostatic spraying method of the present invention, a voltage is applied between a liquid spraying portion having a nozzle of the electrostatic spraying device and a substrate to generate electrostatic force, and the electrostatic force is generated from the nozzle only by the electrostatic force. An electrostatic spraying method of spraying a liquid toward a substrate, wherein a pattern expansion electrode is placed to extend the spray pattern of the liquid sprayed from the nozzle at the same potential as the substrate and the liquid is formed. A spraying step including spraying, the spraying step being a position outside the range where the liquid to be sprayed is present when the liquid is sprayed toward the substrate without using the pattern expansion electrode, The pattern expansion electrode is disposed at a position closer to the object between the nozzle and the object.

(2) In the configuration of the above (1), a rod-shaped electrode is used as the pattern expansion electrode.

(3) In the configuration of the above (1) or (2), the distance from the tip of the nozzle to the pattern expansion electrode is a first distance t1 and is directed to the object without using the pattern expansion electrode When the distance from the tip of the nozzle to the outer edge of the application pattern of the liquid to be applied to the object to be coated when the liquid is sprayed is a second distance t2, the pattern expansion electrode has the first distance t1 It is arrange | positioned in the position within the range which becomes shorter than said 2nd distance t2.

(4) The electrostatic spray device according to the present invention is a liquid spray portion having a nozzle and a pattern expansion electrode for spreading a spray pattern of liquid sprayed from the nozzle, wherein the object to be coated is not using the pattern expansion electrode Conductive or semiconductive at a position outside the range where the liquid to be sprayed is present when the liquid is sprayed toward the target, and at a position near the object between the nozzle and the object to be coated While the potentials of the conductive pattern expansion electrode, the object to be coated, and the pattern expansion electrode are made the same potential, the voltage for generating the electrostatic force to spray the liquid only by the electrostatic force from the nozzle is the coating object And a voltage application unit applied between the pattern expansion electrode and the liquid spray unit.

(5) In the configuration of the above (4), the pattern expansion electrode is rod-like.

(6) In the configuration of the above (4) or (5), the distance from the tip of the nozzle to the pattern expansion electrode is a first distance t1, and the object is directed to the object without using the pattern expansion electrode When the distance from the tip of the nozzle to the outer edge of the application pattern of the liquid to be applied to the object to be coated when the liquid is sprayed is a second distance t2, the pattern expansion electrode has the first distance t1 It is arrange | positioned in the position within the range which becomes shorter than said 2nd distance t2.

  According to the present invention, it is possible to provide an electrostatic spraying method and an electrostatic spraying device therefor which can easily expand the spray range of a liquid according to the change of the range to which the liquid of the object to be coated is desired to be applied. .

It is a perspective view for explaining the electrostatic spraying device of the embodiment concerning the present invention. It is sectional drawing which showed only the liquid spraying part of embodiment which concerns on this invention. It is an expanded sectional view of the tip side of the liquid spraying part of FIG. 2, (a) is a case where the tip surface of a mandrel is located back, (b) is a tip surface of a mandrel front rather than the state of (a). In the case of When the rod-like pattern expansion electrode is not provided, it is a figure for demonstrating the state when the liquid sprayed from the nozzle apply | coats to a to-be-coated-article, (a) is a perspective view, (b) Is a side view. When the rod-shaped pattern expansion electrode is provided, it is a figure for demonstrating the state when the liquid sprayed from the nozzle apply | coats to a to-be-coated-article, (a) is a perspective view, (b) Is a side view. It is a figure for demonstrating the state at the time of moving a pattern expansion electrode according to the change of the range to apply of a to-be-coated-article.

Hereinafter, with reference to the accompanying drawings, modes (hereinafter, embodiments) for carrying out the present invention will be described in detail.
In addition, the same code | symbol is attached | subjected to the same element through the whole description of embodiment.

  Moreover, unless otherwise noted, expressions such as “front (end)” and “front (front)” indicate the spray direction side of the liquid in each member etc., and “rear (end)” and “rear (front)” The expression such as "represents the opposite side of the liquid spray direction in each member or the like.

FIG. 1 is a perspective view for explaining an electrostatic spraying device 10 according to an embodiment of the present invention.
In the present embodiment, a plate material having a to-be-coated surface 40a which is a substantially rectangular flat surface is mentioned as the to-be-coated object 40, but the to-be-coated object 40 is not limited to this. It may have a coated surface which is concave or convex.
In addition, the to-be-coated-article 40 is formed with the protrusion part 40b which protrudes upwards.

As shown in FIG. 1, the electrostatic spray device 10 includes a liquid spray unit 20 having a nozzle 22, a rod-shaped pattern expansion electrode 30 having conductivity or a semiconductive property having a surface resistance of 10 ¹⁰ Ω or less, A voltage application means 50 for applying a voltage between the object 40 and the rod-like pattern expansion electrode 30 and the liquid spray unit 20 is provided.

(Voltage application means)
The voltage application means 50 includes a voltage power supply 51, a first electric wiring 52 for electrically connecting one electrode of the voltage power supply 51 and the liquid spray unit 20, the other electrode of the voltage power supply 51, an object to be coated 40 and a rod shape. And a second electric wire 53 electrically connecting the pattern extension electrode 30 of

  The second electric wiring 53 is provided with a branch wiring that is branched into two on the side opposite to the side connected to the other electrode of the voltage power supply 51, and one branch wiring 53 a of the branch wiring The other branch wiring 53 b is connected to the bar-shaped pattern expansion electrode 30.

In the present embodiment, one branch wiring 53a and the other branch wiring 53b are directly connected to the object 40 and the bar-shaped pattern expansion electrode 30, but these are electrically connected. As long as electrical connection can be made, even if there is a member interposed between one branch wiring 53a and the other branch wiring 53b, the object 40 and the bar-shaped pattern expansion electrode 30, Good.
In addition, since the to-be-coated object 40 and the other electrode of the rod-like pattern expansion electrode 30 and the voltage power supply 51 are connected by the 2nd electric wiring 53, the to-be-coated object 40 and the rod-like pattern expansion electrode 30 have the same potential. It has become.

In the present embodiment, the electrostatic spray device 10 further includes the grounding means 54, and the second electric wiring 53 is connected to the grounding means 54, so the object 40 and the bar-shaped pattern expansion electrode 30 are It is in a grounded state.
Although the grounding means 54 is not an essential requirement, the workpiece 40 may be touched by the worker, so the grounding means 54 is provided to ground the workpiece 40 from the viewpoint of safety. Is preferred.

  Then, later, how the liquid is sprayed will be described, but the voltage application means 50 sets the potential of the object to be coated 40 and the bar-shaped pattern expansion electrode 30 to the first potential which is the same potential. When the electric potential of the portion 20 is a second electric potential, the electric potential difference between the first electric potential and the second electric potential is an electrostatic force that sprays the liquid from the nozzle 22 only with an electrostatic force. A voltage is applied between the object to be coated 40 and the bar-shaped pattern expansion electrode 30 and the liquid spray unit 20 so that the potential difference is sufficient to be generated between the liquid spray units 20.

(Liquid spray part)
FIG. 2 is a cross-sectional view showing only the liquid spray unit 20, and the liquid spray unit 20 also illustrates a state in which a liquid such as a paint is sprayed as described later.

  As shown in FIG. 2, the liquid spray unit 20 includes a body portion 21 made of an insulating material and a liquid flow path 21 b having a liquid supply port 21 a to which the liquid is supplied. A nozzle 22 provided at the tip of the body 21 so as to communicate with the passage 21 b; and a mandrel 23 made of a conductive material disposed in the liquid flow path 21 b of the body 21 and in the through hole of the nozzle 22 There is.

The body portion 21 is provided with a hole 21c communicating with the liquid flow passage 21b in order to take out the mandrel 23 to the rear end side, and in the hole 21c, a gap with the mandrel 23 is sealed. A sealing member 24 is provided to prevent the liquid from leaking.
In the present embodiment, an O-ring is used as the seal member 24. However, the seal member 24 is not limited to the O-ring, and any seal may be used.

  A knob 23a made of an insulating material is provided at the rear end of the stem 23 located on the rear end side of the body 21 through the hole 21c, and is provided to penetrate substantially the center of the knob 23a. An electrical wiring connection 23b made of the conductive material is provided.

  As shown in FIG. 1, the first electric wiring 52 of the voltage application means 50 is connected to the electric wiring connection 23b so that the electric wiring connection 23b is in contact with the mandrel 23. The wiring connection portion 23 b is electrically connected.

  In the present embodiment, the mandrel 23 is an electrode on the liquid spray unit 20 side, but for example, assuming that the nozzle 22 of the liquid spray unit 20 is made of a conductive material, the first electric The wire 52 may be connected, and the nozzle 22 may be an electrode on the liquid spray unit 20 side.

  Further, as shown in FIG. 2, a female screw structure 21e for screwing and connecting the knob 23a is provided on the inner peripheral surface of the rear end opening 21d of the body 21. On the other hand, the tip of the knob 23a A male screw structure 23c is provided on the outer peripheral surface.

Therefore, the mandrel 23 is removably attached to the body portion 21 by screwing the external thread structure 23c of the tip outer peripheral surface of the knob portion 23a with the internal thread structure 21e of the rear end opening 21d of the body portion 21.
Further, by adjusting the screwing amount of the knob portion 23a, the mandrel 23 can be moved in the front-rear direction, and the position of the tip surface 23d of the mandrel 23 can be adjusted in the front-rear direction.

  As described later, clogging may occur because it is difficult to make the opening 22b of the nozzle 22 too large in diameter in order to spray the liquid satisfactorily only by the electrostatic force. As described above, since the mandrel 23 can be moved in the front-rear direction, the clogging can be eliminated by moving the mandrel 23 even if the nozzle 22 is clogged.

  FIG. 3 is an enlarged view of the tip end side of the liquid spray unit 20, and FIG. 3 (a) is a case where the tip end face 23d of the mandrel 23 is located rearward, FIG. 3 (b) is FIG. This is the case where the tip end face 23d of the mandrel 23 is positioned forward of the state of (a).

  As shown in FIG. 3A, the nozzle 22 has a tapered inner diameter portion (see the range W1) with a taper angle α at which the inner diameter is shortened in a tapered manner toward the opening 22b side. Has a tapered portion (see range W2) in which the taper angle at which the outer diameter is shortened toward the end face 23d is β.

The taper angle α of the tapered inner diameter portion of the nozzle 22 is made larger than the taper angle β of the tapered portion of the mandrel 23.
The diameter of the end face 23d of the stem 23 is smaller than the diameter of the opening 22b of the nozzle 22, but the tapered portion of the stem 23 has a gradually larger diameter toward the rear end. And has a portion with a diameter larger than the diameter of the opening 22 b of the nozzle 22.

  As described above, by forming the tip end side of the nozzle 22 and the mandrel 23, as shown in a comparison of FIGS. 3A and 3B, the nozzle 22 and the mandrel 22 are moved in the front-rear direction. The width of the gap formed by the mandrel 23 can be adjusted, and the amount of liquid exiting the opening 22 b of the nozzle 22 can be adjusted.

Further, by moving the mandrel 23 further forward than in the state shown in FIG. 3B, the mandrel 23 can abut on the inner peripheral surface of the nozzle 22, and the opening 22b of the nozzle 22 can be closed. It is.
Therefore, in the state where the liquid is not sprayed, the opening 22 b of the nozzle 22 can be closed by the mandrel 23 to prevent the liquid in the nozzle 22 from being dried, and therefore clogging of the nozzle 22 can be suppressed.

(Basic spray condition of liquid)
Next, the basic state in which the liquid is sprayed from the liquid spray unit 20 will be described first with reference to FIG. 2, and then the state when the liquid 40 is applied to the object 40 will be described.

  The liquid supplied to the liquid supply port 21a of the body portion 21 is supplied to the tip end side of the nozzle 22, and the object 40 and the bar-shaped pattern expansion electrode 30 and the mandrel 23 are applied by the voltage applying means 50 (see FIG. 1). The object to be coated 40 and the bar-like pattern expansion electrode 30 generated by the voltage applied between them and the electrostatic force between the mandrel 23 alone are pulled forward to be detached and atomized forward.

  The state in which the liquid separates and atomizes will be described more specifically. As shown in FIG. 2, the adhesion by the surface tension and viscosity of the liquid to the tip end surface 23d of the mandrel 23 and the tip outer peripheral edge 22a of the nozzle 22 On the other hand, the electrostatic force pulling the liquid forward balances, whereby the liquid supplied to the tip side of the nozzle 22 forms a tailor cone 60 having a conical shape at its tip.

In the tailor cone 60, positive / negative charge separation occurs in the liquid by the action of the electric field, and the meniscus of the tip of the nozzle 22 charged with excess charge is deformed and formed in a conical shape.
Then, the liquid is pulled straight from the tip of the tailor cone 60 by the electrostatic force, the electrostatic explosion occurs at the tip, and the liquid is detached / atomized, that is, sprayed.

  The sprayed liquid, that is, the liquid separated from the nozzle 22 to become liquid particles has a dramatically larger area in contact with air compared to the state before separation, so the vaporization of the solvent is promoted, and the solvent is With vaporization, the distance between charged electrons approaches, and electrostatic repulsion (electrostatic explosion) occurs to break up into liquid particles of smaller particle size.

When this split occurs, the surface area exposed to air is further increased compared to that before the split, so evaporation of the solvent is promoted, electrostatic explosion occurs as described above, and liquid particles of small particle size are further generated. Split up.
Thus, the liquid sprayed from the nozzle 22 by electrostatic explosion is repeated electrostatic explosion even after spraying, whereby atomization is further promoted and the object 40 is applied in the form of extremely small particles. .

  Next, with reference to FIGS. 4 and 5, a state in which the liquid sprayed from the nozzle 22 of the liquid spray unit 20 is applied to the object to be coated 40 will be described.

FIG. 4 is a view for explaining a state where the liquid sprayed from the nozzle 22 is applied to the object 40 when the bar-shaped pattern expansion electrode 30 is not provided, and (a) is a perspective view. It is a figure, (b) is a side view.
FIG. 5 is a view for explaining a state in which the liquid sprayed from the nozzle 22 is applied to the object to be coated 40 when the bar-shaped pattern expansion electrode 30 is provided, and FIG. It is a figure, (b) is a side view.

In the liquid spray unit 20 and the object to be coated 40 shown in FIGS. 4 and 5, the nozzle 22 of the liquid spray unit 20 faces the surface to be coated 40a of the object to be coated 40, and a predetermined distance is maintained between them. It is provided to be
In addition, at least one of the liquid spray unit 20 and the object to be coated 40 is orthogonal to the longitudinal direction of the object to be coated 40 (that is, orthogonal to the axial direction of the nozzle 22) It is provided displaceable along).

In the present embodiment, the liquid spray unit 20 is provided so as to be displaceable along the longitudinal direction of the object to be coated 40.
That is, although not shown, the electrostatic spray device 10 further includes displacement means for displacing the liquid spray unit 20 along the longitudinal direction of the object to be coated 40.

  Specifically, the electrostatic spray device 10 includes, as displacement means, a rail for displacing the liquid spray unit 20 along the longitudinal direction of the object to be coated 40, and a liquid provided to move on the rail A holding unit for holding the spray unit 20 and a drive unit for driving the holding unit to move on the rail are provided, and the liquid spray unit 20 is moved by the movement of the holding unit along the rail. It moves in the longitudinal direction of the coating 40.

However, the displacing means need not be limited to moving the liquid spray unit 20, and may move the object 40 relative to the liquid spray unit 20.
Even in this case, the basic configuration of the displacement means may be the same, and holds the rail provided along the longitudinal direction of the article 40 and the article 40 provided to move on the rail. The displacing means can be constituted by the means and a drive unit for driving the holding means to move on the rails.

Then, toward the object to be coated 40 from the nozzle 22 of the liquid spraying portion 20 while relatively displacing at least one of the liquid spray portion 20 and the object to be coated 40 relatively along the longitudinal direction of the object to be coated 40 The liquid is applied to the substrate 40 by spraying a liquid such as a paint.
Specifically, when the pattern expansion electrode 30 is not provided (see FIG. 4), the liquid is generated only by the electrostatic force generated by the voltage applied between the object 40 and the mandrel 23 by the voltage application means 50. Is pulled forward from the nozzle 22 and sprayed forward.
Then, when the pattern expansion electrode 30 is not provided, as shown in FIG. 4, the range in which the liquid sprayed from the nozzle 22 is present is a side view from the nozzle 22 side of the liquid spray unit 20 in a side view. Although the upper and lower sides of the object 40 have a substantially parabolic shape so as to gradually spread toward the object 40, the region of the protrusion 40b on the upper side of the object 40 can not be covered.
For this reason, the liquid is not applied to the region of the protrusion 40 b to which the liquid is to be applied.

Therefore, in the present embodiment, in order to widen the spray range (spray pattern) of the liquid sprayed from the nozzle 22 of the liquid spray unit 20 so that the liquid is also applied to the area of the protrusion 40b, as shown in FIG. As shown, a bar-shaped pattern expansion electrode 30 having the same potential as the object to be coated 40 is disposed.
Specifically, as shown in FIG. 5 (b), a substantially parabolic range in which the liquid to be sprayed when the liquid is sprayed toward the object to be coated 40 is present without using the bar-like pattern expansion electrode 30. The nozzle 22 and the object to be coated 40 of the liquid spray unit 20 at an outer position (in this example, a position further above the broken line L indicating the upper range in which the liquid is present without the pattern expansion electrode 30). Between the two in the vicinity of the object 40 to be coated.
Further, in the present embodiment, when the bar-shaped pattern expansion electrode 30 draws a circle centered on the axis O of the nozzle 22, the bar-shaped pattern expansion electrode 30 is disposed along the tangential direction (upper tangential direction) with respect to the circle.

  As shown in FIG. 5B, the rod-shaped extended pattern electrode 30 is disposed at a position near the object 40 between the nozzle 22 of the liquid spray unit 20 and the object 40 to be coated. With the shortest position F from the pattern expansion electrode 30 to the axis O of the nozzle 22 as a reference position, the length from the tip of the nozzle 22 to the position F is a first length d1. When the shortest length is set to the second length d2, it means that the bar-shaped pattern expansion electrode 30 is disposed at a position where the second length d2 is shorter than the first length d1.

  Thus, there is a liquid that is sprayed when the liquid is sprayed toward the object to be coated 40 without using the rod-like pattern expansion electrode 30 with the rod-like pattern expansion electrode 30 having the same potential as the object to be coated 40. The liquid spray unit 20 and the object to be coated 40 are disposed at a position outside the substantially parabolic range where the liquid spray unit 20 is disposed and closer to the object to be coated between the nozzle 22 of the liquid spray unit 20 and the object to be coated 40. When the liquid is sprayed while displacing at least one of them along the longitudinal direction of the object to be coated 40, a part of the liquid sprayed toward the surface 40a of the object to be coated 40 from the nozzle 22 Before reaching the to-be-coated surface 40 a of the object to be coated 40, it is pulled to the side of the bar-like pattern expansion electrode 30 which is disposed closer to the object to be coated 40.

For this reason, the range in which the liquid is present is a solid line rather than the dashed line L indicating the upper range in which the liquid to be sprayed is present when the liquid is sprayed toward the coated object 40 without using the bar-like pattern expansion electrode 30. It is further expanded upward as indicated by N.
In the case of this embodiment, since the pattern expansion electrode 30 is disposed only on the upper side, the liquid on the upper side is mainly pulled, and the liquid is sprayed toward the object to be coated 40 without using the pattern expansion electrode 30. When it does, only the upper side is expanded mainly among the existence range of the liquid.
For this reason, the range in which the liquid having a substantially parabolic shape vertically symmetrical in a side view is present becomes an asymmetrical shape such that only the upper side is expanded by arranging the pattern expansion electrode 30, and such a liquid As a result, the liquid sprayed from the nozzle 22 covers the area of the protrusion 40 b of the object 40 and the liquid is also applied to the area of the protrusion 40 b.
Therefore, in the present embodiment, since the protrusion 40 b is on the upper side, the pattern expansion electrode 30 is disposed on the upper side. However, for example, when the protrusion is on the lower side of the object 40, the pattern expansion electrode is 30 may be placed on the lower side, and the range in which the liquid is present may be extended to the lower side.

  Here, as described above, the bar-shaped pattern expansion electrode 30 is disposed at a position close to the object 40 between the nozzle 22 of the liquid spray unit 20 and the object 40, but conversely When the bar-like pattern expansion electrode 30 is disposed closer to the nozzle 22 of the liquid spray unit 20, it becomes impossible to apply a good liquid to the protrusion 40b.

  This is because when the pattern expansion electrode 30 is placed near the nozzle 22, the pattern expansion electrode 30 is also affected by the tailor cone 60 etc., which is the spray start point of the liquid, and the atomized particles are expanded to expand the pattern. In order to affect the direction of electrostatic explosion during electrostatic explosion, etc., it is presumed that the direction of the particles to be sprayed is largely changed to cause a large disturbance to a part of the pattern.

  On the other hand, when the pattern expansion electrode 30 is disposed near the object to be coated 40, the electrostatic explosion is almost complete, and the function of attracting the atomized particles is obtained, and the pattern is deformed without large pattern disturbance. be able to.

  On the other hand, even if the bar-shaped pattern expansion electrode 30 is positioned closer to the object 40 between the nozzle 22 of the liquid spray unit 20 and the object 40, for example, as shown in FIG. If it is too far away from the axis O, that is, too far from the spray range of the liquid, it will not work on the liquid being sprayed.

  Therefore, when the distance from the tip of the nozzle 22 to the bar-shaped pattern expansion electrode 30 is a first distance t1 in side view, the liquid is sprayed toward the object 40 without using the bar-shaped pattern expansion electrode 30. When the distance from the tip of the nozzle 22 to the outer edge M of the application pattern of the liquid to be applied to the object 40 is a second distance t2, the bar-shaped pattern expansion electrode 30 has a first distance t1 being a second distance It is preferable to arrange at a position within a range shorter than t2 and close to the protrusion 40b.

  Further, as in the present embodiment, the rod-shaped pattern expansion electrode 30 is positioned outside the range in which the liquid sprayed when the liquid is sprayed toward the coated object 40 without using the bar-shaped pattern expansion electrode 30. By making it do, it can suppress that a liquid adheres to rod-shaped pattern expansion electrode 30 itself.

  Although the liquid does not adhere to the bar-shaped pattern expansion electrode 30 at all, when the pattern expansion electrode 30 is a bar, the small amount of adhesion and the shape that facilitates cleaning perform the spray of the liquid. The subsequent cleaning of the pattern expansion electrode 30 can be performed extremely easily.

(Modification)
Next, with reference to FIG. 6, a state in which the pattern expansion electrode 30 is moved in accordance with the change in the application range of the object to be coated 40 will be described.
FIG. 6 is a view for explaining a state when moving the pattern expansion electrode 30 in accordance with a change in the application range of the object to be coated 40.

  Also in this modification, the nozzle 22 is displaced while displacing the liquid spray portion 20 or the object to be coated 40 along a linear direction (longitudinal direction of the object to be coated 40) orthogonal to the axial direction of the nozzle 22 (see axis O). The point to which the liquid sprayed from is applied to the substrate 40 is the same as the embodiment described above.

  In the embodiment described above, the liquid is sprayed onto the object 40 without changing the positional relationship between the bar-shaped pattern expansion electrode 30 and the object 40, but it is necessary to be limited thereto Instead, the rod-like pattern expansion electrode 30 is moved in the first direction, which is the axial direction of the nozzle 22, and the displacement direction of the liquid spray unit 20 or the object 40 according to the change in the range where the liquid in the object 40 is desired to be applied. Along a third direction (vertical direction in FIG. 6) which is a direction orthogonal to both directions (first direction and second direction) of the second direction which is the relative movement direction between the spray unit 20 and the object 40 You may move it.

  When the bar-like pattern expansion electrode 30 is moved along the axial direction of the nozzle 22 and the direction perpendicular to the displacement direction of the liquid spray unit 20 or the object 40, the electrostatic spray device 10 is a bar-like pattern expansion electrode A moving means (not shown) may be provided to move the head 30 along a third direction (vertical direction in FIG. 6) orthogonal to the first direction and the second direction.

For example, when the area to which the liquid of the object to be coated 40 is to be applied gradually expands, the moving means moves the rod-like pattern expanding electrode 30 away from the axis O of the nozzle 22 and the axial direction of the nozzle 22 and the liquid spray portion 20 or the object It is moved along the direction orthogonal to the displacement direction of the paint 40.
When the range to which the liquid of the object to be coated 40 is desired to be applied is gradually narrowed, the moving means moves the rod pattern extended electrode 30 in the direction of approaching the axis O of the nozzle 22 It is moved along the direction orthogonal to the displacement direction of the paint 40.

Specifically, as shown in FIG. 6, in the region A, when the liquid spray unit 20 is displaced from one end (left end) of the coated object 40 toward the other end (right end) of the coated object 40, The moving means moves the bar-shaped pattern expansion electrode 30 gradually upward because the area to which the liquid of the object to be coated 40 is to be applied is gradually expanded.
On the other hand, in the region B, the region where the liquid 40 to be coated is desired to be applied is gradually narrowed. Therefore, after the liquid spray portion 20 reaches the boundary position between the region A and the region B, the moving means The bar-like pattern expansion electrode 30 is gradually moved downward.

  Thus, depending on the change in the range in which the liquid of the object to be coated 40 is desired to be applied, the bar-shaped pattern expansion electrode 30 is perpendicular to the axial direction of the nozzle 22 and the displacement direction of the liquid spray unit 20 or the object 40 By moving along the surface, the liquid can be applied well to the object to be coated 40 in accordance with the change of the range to which the liquid of the object to be coated 40 is to be applied.

  When the bar-like pattern expansion electrode 30 is shorter than the object to be coated 40, it may be provided to be displaceable along the longitudinal direction of the object to be coated following the displacement of the liquid spray unit 20.

  As described above, the present invention is not limited to the above embodiment, and those appropriately modified or improved are also included in the technical scope of the present invention, which is a patent for those skilled in the art. It is clear from the description of the claims.

DESCRIPTION OF SYMBOLS 10 Electrostatic spraying apparatus 20 Liquid spraying part 21 Body part 21a Liquid supply port 21b Liquid flow path 21c Hole part 21d Rear end opening part 21e Female screw structure 22 Nozzle 22a Tip outer periphery 22b Opening part 23 Bar 23a Picking part 23b Electrical wiring connection Part 23c Male thread structure 23d Tip surface 24 Seal member 30 Pattern expansion electrode 40 To-be-coated object 40a To-be-coated surface 40b Protrusion 50 Voltage application means 51 Voltage power supply 52 First electric wiring 53 Second electric wiring 53a One branch wiring 53b The other Branch wiring 54 Grounding means 60 Taylor cone

Claims (6)

An electrostatic force is generated by applying a voltage between a liquid spray unit having a nozzle of an electrostatic spray device and a coated object to generate an electrostatic force, and the liquid is sprayed from the nozzle toward the coated object only by the electrostatic force. A spraying method,
Including a step of disposing a pattern expansion electrode which is brought to the same potential as the object to be coated and spreads a spray pattern of the liquid sprayed from the nozzle to spray the liquid.
The spray step is a position outside the range where the liquid to be sprayed is present when the liquid is sprayed toward the coated object without using the pattern expansion electrode, and the nozzle and the coated object An electrostatic spray method characterized in that the pattern expansion electrode is disposed at a position near the object to be coated.   The electrostatic spray method according to claim 1, wherein a rod-shaped electrode is used as the pattern expansion electrode. When the distance from the tip of the nozzle to the pattern expansion electrode is a first distance t1 and the liquid is sprayed toward the object without using the pattern expansion electrode, the object from the tip of the nozzle is the object to be coated When the distance to the outer edge of the application pattern of the liquid applied to the surface is the second distance t2,
The electrostatic spray method according to claim 1 or 2, wherein the pattern expansion electrode is disposed at a position where the first distance t1 is shorter than the second distance t2. A liquid spray unit having a nozzle;
It is a pattern expansion electrode which spreads the spray pattern of the liquid sprayed from the said nozzle, Comprising: When the liquid is sprayed toward a to-be-coated-article without using the said pattern expansion electrode, the said range of the liquid to be sprayed exists. A conductive or semiconductive pattern expansion electrode disposed at a position near the object between the nozzle and the object;
The voltage to generate the electrostatic force for spraying the liquid only by the electrostatic force from the nozzle while keeping the potential of the object to be coated and the pattern extension electrode the same potential as the object to be coated and the pattern extension electrode An electrostatic spray apparatus comprising: voltage applying means for applying between liquid spray units.   The electrostatic spray device according to claim 4, wherein the pattern expansion electrode is rod-like.   When the distance from the tip of the nozzle to the pattern expansion electrode is a first distance t1 and the liquid is sprayed toward the object without using the pattern expansion electrode, the object from the tip of the nozzle is the object to be coated When the distance to the outer edge of the application pattern of the liquid applied to the surface is a second distance t2, the pattern expansion electrode is disposed at a position within a range where the first distance t1 is shorter than the second distance t2 The electrostatic spray device according to claim 4 or 5, characterized in that:

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