JP2019058864A - Electrostatic spray method and electrostatic spray device for the electrostatic spray method - Google Patents

Abstract

To provide an electrostatic spray method capable of partially changing the coating amount of a liquid coating a coating object.SOLUTION: In an electrostatic spray method coating a coating object 40 with a liquid only by an electrostatic force from the liquid spray part 20 of an electrostatic spray device 10,: the conductive or semiconductive attraction electrode 30 of the electrostatic spray device 10 is disposed at a first position close to the coating object 40; a voltage generating the electrostatic force between the coating object 40 and an attraction electrode 30 and the liquid spray part 20 is applied while the coating object 40 and the attraction electrode 30 have the same electric potential; a spray step spraying the liquid toward the coating object 40 is included; the first position is a position within an existing range of the coating liquid of the coating object 40 among spraying liquids when the attraction electrode 30 is not disposed; and a part of the liquid which should be coated to the coating object 40 is attracted to the attraction electrode 30 and not coated to the coating object 40 when the attraction electrode 30 is not disposed in the spray step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic spraying method and an electrostatic spraying device for the electrostatic spraying method.

Patent Document 1 discloses an electrostatic spray device which sprays a liquid onto a substrate by electrostatic force alone.
This electrostatic sprayer is provided with a collection body for collecting a liquid that can not be applied to the object to be coated, and the liquid can be sprayed without contaminating the surroundings with the liquid that can not be applied to the object to be coated. .

JP, 2016-137428, A

  By the way, in the case where the liquid is sprayed toward the object to be coated only by the electrostatic force from the nozzle for spraying the liquid of the electrostatic spray device, it is, for example, a rod-like object to be coated. When spraying can not be performed, the amount of applied liquid on the rear side is larger on the side facing the nozzle of the object (hereinafter also referred to as the front side) and the opposite side (hereinafter referred to as the rear side) Tend to be

For this reason, for example, in order to make the amount of application of the liquid uniform in the circumferential direction of the object to be coated, it is necessary to change the amount of application of the liquid on the rear side of the object to be reduced.
In addition to the above, it is also conceivable to change the amount of applied liquid in the longitudinal direction of the rod-like object to be coated.

  This invention is made in view of such a situation, and the electrostatic spraying method which can change the application quantity of the liquid to apply with respect to a to-be-coated-article partially, and its electrostatic spraying method The purpose of the invention is to provide an electrostatic spray device for

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) The electrostatic spraying method of the present invention is an electrostatic spraying method in which a liquid is sprayed only from electrostatic force from a liquid spraying unit having a nozzle of an electrostatic spraying device to apply the liquid to a substrate to be coated, The conductive or semiconductive adsorption electrode of the electrostatic spray device is disposed at a first position near the substrate to be coated while the substrate and the adsorption electrode are kept at the same potential. Applying a voltage for generating the electrostatic force between the adsorption electrode and the liquid spray unit to spray the liquid toward the object to be coated, the first position including the adsorption electrode It is a position within the range in which the liquid to be applied to the object to be coated is present among the liquids to be sprayed, if not provided, and the object to be coated is not provided with the adsorption electrode, Part of the liquid that should have been applied to the Te, is performed so as not to coated on the object to be coated.

(2) In the configuration of the above (1), the liquid spray portion side is the front side of the substrate and the side opposite to the front side is the rear side, as viewed from the substrate. If the side surface is a side, the spraying step is performed in a state where the adsorption electrode is disposed on the rear side or the side of the object to be coated and the object to be coated is fixed.

(3) In the configuration of the above (1), the liquid spray portion side is the front side of the substrate and the side opposite to the front side is the rear side, as viewed from the substrate. And the spraying step is such that the separation distance between the adsorption electrode and the substrate changes at least in part along the rear side and the side of the substrate. The adsorption electrode is disposed along the lateral side of the object to be coated, and the object to be coated is rotated.

(4) In the configuration of the above (3), the spraying step is performed by disposing the adsorption electrodes on each of the opposite side sides of the object to be coated.

(5) In the configuration of any one of the above (1) to (4), an elongated rod-like electrode is used as the adsorption electrode.

(6) In the configuration of any one of the above (1) to (5), the first position is a position where at least a part of the adsorption electrode is located within 20 mm as a distance from the object to be coated.

(7) The electrostatic spray device according to the present invention is an electrostatic spray device which sprays a liquid toward a substrate with only electrostatic force, and the electrostatic spray device includes a liquid spray unit having a nozzle, A conductive or semiconductive adsorption electrode disposed at a first position near the substrate, and the substrate, the adsorption electrode, and the liquid while maintaining the substrate and the adsorption electrode at the same potential. And voltage applying means for applying a voltage between the spray units to generate the electrostatic force, wherein the first position corresponds to the object to be coated among the liquids to be sprayed when the adsorption electrode is not provided. It is a position within the range where the liquid to be applied is present.

(8) In the configuration of the above (7), the electrostatic spray device includes fixing means for fixing the object to be coated, and the liquid spray portion side is the front side of the object to be coated when viewed from the object to be coated When the side opposite to the front side is the rear side and the remaining side is the side, the adsorption electrode is disposed on the rear side or the side of the fixed object to be coated.

(9) In the configuration of the above (7), the electrostatic spray device includes a rotating means for rotating the object to be coated, and the liquid spray portion side is the front side of the object to be coated when viewed from the object to be coated When the side opposite to the front side is the rear side and the remaining side is the side, the adsorption electrode is at least a part of the part along the side of the object to be rotated. It is disposed along the lateral side of the substrate such that the separation distance between the adsorption electrode and the substrate changes.

(10) In the configuration of the above (9), the electrostatic spray device is provided with a pair of the adsorption electrodes arranged on each of opposite side sides of the object to be coated.

(11) In the configuration of any one of the above (7) to (10), the adsorption electrode is in the shape of an elongated rod.

(12) In the configuration according to any one of (7) to (11), the first position is a position where at least a part of the adsorption electrode is located within 20 mm as a distance from the object to be coated.

  According to the present invention, there is provided an electrostatic spraying method capable of partially changing the application amount of a liquid to be applied to a substrate, and an electrostatic spraying device for the electrostatic spraying method. Can.

It is a perspective view for demonstrating the electrostatic spraying apparatus of 1st Embodiment which concerns on this invention. It is sectional drawing which showed only the liquid spraying part of 1st Embodiment concerning 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 It is the figure which showed that the liquid sprayed from the nozzle of 1st Embodiment which concerns on this invention adheres to a to-be-coated-article, (a) is a figure which shows the case where an adsorption electrode is arrange | positioned, (b) These are figures which show the case where the adsorption electrode is not arrange | positioned. It is a perspective view for demonstrating the electrostatic spraying apparatus of 2nd Embodiment which concerns on this invention.

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 number or 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.

First Embodiment
FIG. 1 is a perspective view for explaining an electrostatic spraying device 10 according to a first embodiment of the present invention.
As shown in FIG. 1, the electrostatic spray device 10 includes a liquid spray unit 20 having a nozzle 22, a conductive or semiconductive adsorption electrode 30 having a surface resistance of 10 ¹⁰ Ω or less, an adsorption electrode 30, and a coating material A voltage application means 50 for applying a voltage between the object 40 and the liquid spray unit 20 is provided.

  The voltage application means 50 includes a voltage power supply 51, a first electric wiring 52 electrically connecting one of the electrodes of the voltage power supply 51 and the liquid spray unit 20, the other electrode of the voltage power supply 51, the adsorption electrode 30, and a coating And a second electric wire 53 electrically connecting the object 40.

  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 a first branch wiring 53a that is one branch wiring of the branch wiring. Are connected to the object to be coated 40, and the second branch wiring 53b, which is the other branch wiring, is connected to the adsorption electrode 30.

In the present embodiment, the case where the first branch wiring 53a and the second branch wiring 53b are directly connected to the object to be coated 40 and the adsorption electrode 30 is shown, but these are electrically connected. Just do it.
Therefore, as long as electrical connection between the first branch wiring 53a and the second branch wiring 53b and the object to be coated 40 and the adsorption electrode 30 can be made, the first branch wiring 53a and the second branch wiring 53b and the coating target are coated. There may be a member interposed between the object 40 and the adsorption electrode 30.
In addition, since the to-be-coated object 40, the adsorption electrode 30, and the other electrode of the voltage power supply 51 are connected by the 2nd electric wiring 53, the to-be-coated object 40 and the adsorption electrode 30 have the same electric potential and will be described later As such, even if the adsorption electrode 30 is disposed at a position near the object to be coated 40, generation of sparks and the like can be avoided.

In the present embodiment, the electrostatic spraying device 10 is provided with the grounding means 54, and the second electric wiring 53 is connected to the grounding means 54. Therefore, the object 40 and the attraction electrode 30 are in the state of being grounded. It has become.
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 adsorption electrode 30 to the first potential which is the same potential. Assuming that the electric potential 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 by the electrostatic force. A voltage is applied between the object to be coated 40 and the adsorption electrode 30 and the liquid spray unit 20 so as to have a potential difference sufficient to be generated.

  Therefore, in the electrostatic spraying method using the electrostatic spraying device 10, the spraying step of spraying the liquid maintains the object to be coated 40 and the adsorption electrode 30 at the same potential, while the object to be coated 40 and the adsorption electrode 30 and the liquid are sprayed A voltage generating electrostatic force is applied between the sections 20, and the liquid is sprayed toward the object 40 only by the electrostatic force generated by the application of the voltage.

(Liquid spray unit 20)
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 cross-sectional view of the tip end side of the liquid spray unit 20 of FIG. 2, and FIG. 3 (a) is a case where the tip surface 23d of the mandrel 23 is located backward; Is a case where the tip end face 23d of the mandrel 23 is positioned forward of the state of FIG. 3 (a).

  As shown in FIG. 3A, the nozzle 22 has a tapered inner diameter portion (see the range W1) with a taper angle α, the inner diameter of which decreases in a tapered manner toward the opening 22b side. Has a tapered portion (see the range W2) in which the taper angle at which the outer diameter decreases 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, so 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 voltage applying means 50 (see FIG. 1) Only the electrostatic force between the object to be coated 40 and the adsorbing electrode 30 and the mandrel 23 generated by the voltage applied to it is pulled forward and it is separated 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 electrostatic force, 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 the 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 further increases compared to that before the split, so the vaporization of the solvent is promoted, the electrostatic explosion occurs as described above, and the liquid with a smaller particle size is further generated. It breaks up into particles.
As described above, the liquid sprayed from the nozzle 22 by electrostatic explosion is further repeatedly atomized after atomization, whereby atomization is further promoted and applied to the substrate 40 in the form of extremely small particles. become.

  Next, a state in which the liquid sprayed from the nozzle 22 is applied to the object to be coated 40 will be described while describing the position and the like where the adsorption electrode 30 is disposed.

As shown in FIG. 1, the object to be coated 40 is in the shape of a cylindrical rod, and the adsorbing electrode 30 is also rod-shaped (in this example, the outer shape is arranged so as to be disposed along the length direction of the object 40). It is a square rod-shaped body).
And this adsorption | suction electrode 30 is arrange | positioned at the 1st position near the to-be-coated-article 40. FIG.

  Specifically, in the first position, the object to be coated 40 is disposed so that the liquid is sprayed from the nozzle 22 of the liquid spray unit 20 toward the object to be coated 40 only by the electrostatic force without providing the adsorption electrode 30. When a voltage is applied between the liquid spray units 20, the position is within the range in which the liquid to be applied to the substrate 40 is present.

  When the adsorption electrode 30 is disposed at such a first position, as described above, the adsorption electrode 30 is maintained at the same potential as the object 40 to be coated, so that the adsorption electrode 30 itself is also coated with liquid. Target.

  For this reason, in the state where the adsorption electrode 30 is disposed at the first position, when the spraying step of spraying the liquid is performed while moving the liquid spraying unit 20 along the object 40, the spraying step is performed by the adsorption electrode 30. If the liquid is not disposed, a part of the liquid that should have been applied to the object to be coated 40 is adsorbed to the adsorption electrode 30 and not applied to the object to be coated 40.

  FIG. 4 is a view showing that the liquid sprayed from the nozzle 22 is applied to the object to be coated 40, and FIG. 4 (a) is a view showing the case where the adsorption electrode 30 is disposed. b) is a figure which shows the case where the adsorption electrode 30 is not arrange | positioned.

  As described above, since the liquid is so strongly charged that it is sprayed from the nozzle 22 by electrostatic explosion, the liquid is strongly attracted to the coated object 40 by the electrostatic force.

  Therefore, when the nozzle 22 side (liquid spray unit 20 side) is the front side of the substrate 40 and the side opposite to the front side is the rear side, as viewed from the substrate 40, as shown in FIG. As shown in FIG. 5, even if the liquid particles have passed through the left and right outer sides of the object to be coated 40, the liquid particles are strongly drawn to the side of the object to be coated 40 so as to be attracted to the back side of the object 40 to be coated.

  Then, the object 40 is fixed only by the fixing means for fixing the object 40 (not shown) of the electrostatic spray device 10, and when the object 40 does not rotate, the left and right outer sides of the object 40 are The liquid which has flowed in is applied to the rear side of the object to be coated 40, and the rear side of the object to be coated 40 has a thicker film thickness than the other portions in the circumferential direction (dotted circle encircling portion A Reference) will be formed.

  On the other hand, as shown in FIG. 4A, the liquid to be applied to the object to be coated 40 among the liquids to be sprayed when the adsorption electrode 30 is not provided on the rear side of the object to be fixed 40 fixed. When the adsorption electrode 30 is disposed at a position near the object 40, such as a first position (for example, a position within 20 mm from the object 40) within the range where the Since a part of the liquid that has wound around the left and right outer sides of the object 40 is adsorbed to the adsorption electrode 30 and does not adhere to the rear side of the object 40, the protruding portion (dotted circle encircling portion seen in FIG. A) can be suppressed.

  The appropriate distance between the object to be coated 40 and the adsorption electrode 30 changes depending on the size (outer diameter) of the object to be coated 40. It is preferable to provide a distance adjusting means capable of adjusting the distance from the object 40, and even if the distance adjusting means adjusts the distance at the time of the initial setting, when performing the spraying step The distance may be changed.

  Further, in the present embodiment, the case where protrusion is not allowed to the rear side of the object to be coated 40 is described, but when it is desired to make the film thickness thinner only on the rear side of the object to be coated 40 If it is arranged close to the coating 40, the amount of liquid adsorbed to the adsorption electrode 30 is increased. Therefore, if the adsorption electrode 30 is used, the film thickness can be reduced only at the rear side of the object 40. It is.

  As described above, in the first embodiment, when the object to be coated 40 is in a fixed state (a state in which it can not rotate in the circumferential direction), the application amount of the liquid applied to the object to be coated 40 is partially The thickness of the coating on the rear side of the article 40 is made to be substantially the same as that of the other portion in the circumferential direction, or conversely, thinner than that of the other portion in the circumferential direction. Partial adjustment of the thickness of the coating film is possible.

  In the above description, the outer shape of the adsorption electrode 30 is a square, but the outer shape of the adsorption electrode 30 is not limited to a square, and may be another polygonal shape (for example, a triangle or the like). It may be.

  However, as will be understood from the above description, since the liquid adheres to the adsorption electrode 30, it is easy to carry out a cleaning operation to wash away the adhered liquid after the spraying of the liquid is finished as a rod-like one. It is preferable to do.

Second Embodiment
FIG. 5 is a perspective view for explaining an electrostatic spraying device 10 according to a second embodiment of the present invention.
Also in the second embodiment, the basic configuration of the electrostatic spray device 10 is the same as that of the first embodiment, and therefore, in the following, the description of the same points as the first embodiment is omitted. I will explain the differences.

  As shown in FIG. 5, in the second embodiment, the liquid spray unit 20 side is the front side of the substrate 40 and the side opposite to the front side is the rear side, as viewed from the substrate 40, Assuming that the remaining side is the side (in the figure, both the upper and lower sides of the substrate 40), the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) ) Are placed.

  The adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) has one end side (the left side in the figure) as viewed across the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B). The linear portion has a first end (left end) and a second end (right end) disposed along the object 40 so that the distance between the object 40 and the object 40 is substantially constant.

  Further, the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is further viewed from the second end of the linear portion in the entire adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) The other end side (right side in the figure) of the case is disposed along the object 40 so that the distance between the object 40 and the object 40 gradually changes (becomes gradually longer). It is considered to be an inclined straight portion inclined to the opposite side.

That is, the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is formed in a V-shaped rod shape (a V-shaped rod-like body).
The outer shape of the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is circular.

  The second electric wiring 53 is provided with a branch wiring that is branched into three on the side opposite to the side connected to the other electrode of the voltage power supply 51, and one of the branch wirings is a first branch wiring 53a. Is electrically connected to the object to be coated 40, and the other second branch wiring 53b, which is another branch wiring, is electrically connected to one of the adsorption electrodes 30A of the adsorption electrodes 30, and the remaining 1 The third branch wiring 53c, which is one branch wiring, is electrically connected to the other adsorption electrode 30B of the adsorption electrodes 30 provided with a pair.

  In the second embodiment, the object to be coated 40 is rotatably held in the circumferential direction by rotating means (not shown), and the first branch wiring 53 a connected to the object to be coated 40 is attached to the object to be coated 40. Rather than being fixed, it is in a state of contact only to allow electrical connection.

  In addition, the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is disposed such that at least a portion (specifically, a portion of the linear portion) is located within 20 mm from the object 40 It is done.

In the second embodiment, the spraying step is performed to move the liquid spray unit 20 along the object 40 while rotating the object 40 in the circumferential direction.
Then, the portion of the linear portion of the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) disposed closest to the object to be coated 40 has an adsorption electrode 30 (one When the adsorption electrode 30A and the other adsorption electrode 30B are not provided, a large amount of liquid that should have been applied to the object to be coated 40 is adsorbed, and the film thickness becomes thin.

  In addition, since the linear portion is disposed along the object to be coated 40 so that the separation distance between the linear portion and the object to be coated 40 is substantially constant, in the range of the object to be coated 40 corresponding to the linear portion The thickness of the coating formed on the substrate 40 is substantially uniform.

  On the other hand, in the portion of the inclined linear portion, the distance between the object to be coated 40 gradually increases toward the other end side as viewed in the whole of the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B). Therefore, the amount of the liquid adsorbed to the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) decreases toward the other end, and conversely, the liquid applied to the object 40 The amount of

  Therefore, in the range of the object to be coated 40 corresponding to the inclined linear portion, the object 40 is directed toward the end of the object to be coated 40 (the end on the right side of the object 40 of FIG. 5). The liquid is applied so that the thickness of the formed coating becomes gradually larger.

In the above, although the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is disposed on each of the opposite side sides of the object to be coated 40, even if either one is disposed. It is likewise possible to vary the thickness of the coating.
However, when the adsorption electrodes 30 (one adsorption electrode 30A and the other adsorption electrode 30B) are arranged on each of the opposite side sides of the object to be coated 40, the thickness of the coating film can be easily controlled.

Moreover, although the adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) is a V-shaped rod-like body in the above, it is not necessary to limit to it.
For example, in the case of gradually increasing or decreasing the thickness of the coating film from the first end (left end) to the second end (right end) of the substrate 40, a straight straight line The adsorption electrode 30 (one adsorption electrode 30A and the other adsorption electrode 30B) may be inclined to the object 40 and disposed.

  As mentioned above, although the electrostatic spraying apparatus 10 of this invention was demonstrated based on specific embodiment, this invention is not limited to said specific embodiment, A deformation | transformation and improvement are given suitably Those included in the technical scope of the present invention are obvious to the person skilled in the art 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 Section 23c Male thread structure 23d Tip surface 24 Seal member 30 Adsorption electrode 30A One adsorption electrode 30B Another adsorption electrode 40 Substrate 50 Voltage application means 51 Voltage power source 52 First electric wiring 53 Second electric wiring 53a First branch wiring 53b second branch wiring 53c third branch wiring 54 grounding means 60 tailor cone

Claims (12)

An electrostatic spraying method of spraying a liquid from a liquid spraying unit having a nozzle of an electrostatic spraying device only by electrostatic force to apply the liquid to a substrate.
The conductive or semiconductive adsorbing electrode of the electrostatic spray device is disposed at a first position near the article to be coated while the article to be coated and the adsorption electrode are kept at the same potential. And applying a voltage that generates the electrostatic force between the adsorption electrode and the liquid spray unit to spray the liquid toward the substrate;
The first position is a position within a range in which the liquid to be applied to the object to be coated is present among the sprayed liquid when the adsorption electrode is not provided.
If the spray step does not arrange the adsorption electrode, a part of the liquid that should have been applied to the article is adsorbed onto the adsorption electrode and not applied to the article. An electrostatic spray method characterized in that it is carried out.   Assuming that the liquid spray portion side is the front side of the substrate, the side opposite to the front side is the rear side, and the remaining side is the side, as viewed from the substrate, the spraying step 2. The electrostatic spray method according to claim 1, wherein the adsorption electrode is disposed on the rear side or the side of the object to be coated, and the object to be coated is fixed.   Assuming that the liquid spray portion side is the front side of the substrate, the side opposite to the front side is the rear side, and the remaining side is the side, as viewed from the substrate, the spraying step Along the lateral side of the substrate such that the separation distance between the adsorbing electrode and the substrate changes at least in part along the rear side and the lateral side of the substrate; The electrostatic spray method according to claim 1, wherein the adsorption electrode is disposed, and the object to be coated is rotated.   The electrostatic spraying method according to claim 3, wherein the spraying step is performed by arranging the adsorption electrodes on each of opposite side sides of the object to be coated.   The electrostatic spray method according to any one of claims 1 to 4, wherein an elongated rod-like electrode is used as the adsorption electrode.   The said 1st position is a position where at least one copy of the said adsorption electrode is located within 20 mm by the distance from the said to-be-coated-article, The any one of the Claims 1-5 characterized by the above-mentioned. Electrostatic spraying method. An electrostatic sprayer for spraying a liquid onto a substrate by electrostatic force alone,
The electrostatic spray device is
A liquid spray unit having a nozzle;
A conductive or semiconductive adsorption electrode disposed at a first position near the substrate;
And voltage applying means for applying a voltage between the object to be coated and the adsorption electrode and the liquid spray section to generate the electrostatic force while maintaining the object to be coated and the adsorption electrode at the same potential.
The electrostatic spray device according to claim 1, wherein the first position is a position within a range where the liquid to be applied to the object to be coated is present among the sprayed liquid when the adsorption electrode is not provided. The electrostatic spray device comprises fixing means for fixing the object to be coated,
When the liquid spray part side is the front side of the coated article, the side opposite to the front side is the rear side, and the remaining side is the side, as viewed from the article, the adsorption electrode The electrostatic spray device according to claim 7, wherein the electrostatic spray device is disposed on the rear side or the side of the fixed object to be coated. The electrostatic spray device comprises rotating means for rotating the object to be coated,
When the liquid spray part side is the front side of the coated article, the side opposite to the front side is the rear side, and the remaining side is the side, as viewed from the article, the adsorption electrode Along the lateral side of the substrate such that the separation distance between the adsorbing electrode and the substrate changes at least in part along the lateral side of the rotating substrate. An electrostatic spray device according to claim 7, characterized in that it is arranged.   The said electrostatic spraying apparatus is equipped with a pair of said adsorption | suction electrode arrange | positioned at each of the side side which the to-be-coated-article opposes, The electrostatic spraying apparatus of Claim 9 characterized by the above-mentioned.   The electrostatic spray device according to any one of claims 7 to 10, wherein the adsorption electrode is an elongated rod shape.   The said 1st position is a position where at least one copy of the said adsorption electrode is located within 20 mm by the distance from the said to-be-coated-article, The any one of the Claims 7 to 11 characterized by the above-mentioned. Electrostatic sprayer.