JP5613078B2 - Electrostatic liquid applicator - Google Patents

Description

  The present invention applies a voltage having a polarity opposite to that of a material to be coated to a conductive member provided in a nozzle, and supplies a coating liquid supplied to a liquid flow path between the main body portion of the nozzle and the conductive member. The present invention relates to an electrostatic liquid coating apparatus that discharges from a discharge port of a nozzle while being charged to the same polarity as that of the liquid and adheres to a material to be coated.

  As a conventional electrostatic liquid coating apparatus, for example, a device described in Patent Document 1 below is known. The electrostatic liquid coating apparatus includes a pair of nozzle blades made of an electrically insulating material facing each other across a slit, and a shim made of a conductive material is disposed in the slit between the nozzle blades. A liquid flow path is formed between the shims. Then, a high voltage having a polarity opposite to that of the material to be coated is applied to the shim, and the coating liquid supplied to the liquid flow path is discharged from the nozzle outlet while being charged to the same polarity as the shim and is attached to the material to be coated. Apply.

JP 2002-79144 A

  In such an electrostatic liquid application apparatus, when a high voltage is applied to the shim, a high-potential electrostatic field is generated. Therefore, a certain distance (for example, to prevent people from approaching the electrostatic liquid application apparatus) In order to earn an interval of 40 cm to 80 cm, it was necessary to cover with a large protective cover.

  For this reason, in the conventional electrostatic liquid coating apparatus, the entire apparatus is increased in size by the provision of the relatively large protective cover as described above, and the handleability is also deteriorated.

  Therefore, an object of the present invention is to improve the handleability by suppressing the enlargement of the entire apparatus.

The present invention applies a voltage having a polarity opposite to that of the material to be applied to the conductive member provided in the nozzle, and supplies the coating liquid supplied to the liquid flow path between the main body portion of the nozzle and the conductive member. In an electrostatic liquid coating apparatus that discharges from the discharge port of the nozzle while being charged with the same polarity as that of the conductive member, and adheres to the material to be coated. An electrostatic field shielding member that shields an electrostatic field that is generated when an electric field is applied, and the electrostatic field shielding member includes a wall portion on the opposite side to the discharge port of the nozzle, and a wall portion surrounding the side periphery of the nozzle. And a liquid collecting part that is provided so as to surround the periphery of the nozzle excluding at least a part corresponding to the discharge port on the discharge port side of the nozzle and is supplied with a liquid from a liquid storage tank that stores the liquid Supply of fluid between the nozzle and the liquid flow path of the nozzle The liquid supply pipe is formed in a coil shape and disposed outside the electrostatic field shielding member, and voltage applying means for applying a voltage having a polarity opposite to the material to be coated to the conductive member, It is attached to the outer wall of the electrostatic field shielding member .

  According to the present invention, an electrostatic shielding member that shields an electrostatic field that is generated when a voltage is applied to a conductive member provided in a nozzle, except for at least a part corresponding to the discharge port on the discharge port side of the nozzle. Therefore, it is not necessary to provide a large protective cover for earning a certain distance so that a person cannot approach the electrostatic field, and the overall size of the apparatus can be suppressed.

(A) is a side view of an electrostatic liquid coating apparatus according to an embodiment of the present invention, and (b) is an operation explanatory view showing a state in which the entire apparatus is rotated 90 degrees with respect to (a). FIG. 2 is a front view of the electrostatic liquid coating apparatus of FIG. 1. It is a top view of the electrostatic type liquid application device of FIG. It is sectional drawing of the nozzle in the electrostatic-type liquid application device of FIG. It is a whole block diagram containing the liquid circuit of the electrostatic-type liquid application device of FIG. It is a perspective view which shows the state which installed the electrostatic type liquid application apparatus of FIG. 1 in the conveyor apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 to 3, the electrostatic liquid coating apparatus according to an embodiment of the present invention includes a nozzle 1 for discharging a conductive liquid, and a liquid discharge port at the tip (lower end) of the nozzle 1. An electrostatic field shielding cover 5 serving as an electrostatic field shielding member is provided so as to surround the periphery of the nozzle 1 except for the third side (lower side in FIG. 1A). As shown in FIG. 2, the nozzle 1 has a certain length. Therefore, the electrostatic field shielding cover 5 has a rectangular parallelepiped shape that is long in the left-right direction in FIG. 2 in accordance with the length of the nozzle 1. .

  The electrostatic field shielding cover 5 described above includes an upper wall 5a, a front wall 5b located on the right side in FIG. 1A, a rear wall 5c located on the left side, and a pair of left and right side walls 5d, FIG. 5e and made of, for example, a polyacetal resin (for example, trademark registered name “Derlin”), and the thickness of each wall 5a to 5e is 15 to 20 mm when using Delrin.

  The front end (lower end in FIG. 1A) of the electrostatic field shielding cover 5 is located in front of the liquid discharge port 3 of the nozzle 1 (downward in FIG. 1A). In addition, as for both side walls 5d and 5e, the tip (lower end in FIG. 1A) of a fixture 36 (FIG. 2), which will be described later, attached to the inner wall is forward of the liquid discharge port 3 of the nozzle 1 ( It is located in the lower part in FIG. Moreover, the nozzle 1 is attached to the lower surface of the upper wall 5a via a pair of support tools 6 in the vicinity of both left and right ends in FIG.

  On the upper wall 5a of the electrostatic field shielding cover 5, a high voltage generator 7 as a voltage applying means for generating a negative direct current voltage, and a manifold as a liquid collecting portion through which the liquid supplied to the nozzle 1 flows. 9 is installed. The manifold 9 is formed long in the left-right direction in FIG. 2 according to the length of the nozzle 1, and a plurality of electromagnetic valves 11 are connected along the length direction.

  The solenoid valve 11 and the nozzle 1 are connected by a liquid supply tube 13 serving as a liquid supply pipe having a coil shape. The electromagnetic valve 11 is arranged on the right side of the manifold 9 in FIG. 1A, and the liquid supply tube 13 is directed downward in the vertical direction in the state of being close to the front wall 5 b of the electrostatic field shielding cover 5. Arranged.

  The upstream end of the liquid supply tube 13 protrudes upward and is connected to the connection port 11 a of the electromagnetic valve 11. On the other hand, the downstream end of the liquid supply tube 13 is inserted into the inside of the electrostatic field shielding cover 5 through a through hole 5bh formed in the front wall 5b of the electrostatic field shielding cover 5, and is formed on the side of the nozzle 1. The liquid inlet 15 is connected. The liquid supply tube 13 is omitted in FIGS.

  As shown in FIG. 3, the high voltage generator 7 is arranged at the center in the longitudinal direction of the electrostatic field shielding cover 5 and on the side close to the rear wall 5c, and as shown in FIG. 15 is connected to a connector pin 17 projecting from a side surface opposite to 15 via a connection terminal 19. The connection terminal 19 protrudes inside through a through hole 5ah formed in the upper wall 5a of the electrostatic field shielding cover 5. Reference numeral 20 denotes a terminal for taking in electric power supplied to the high voltage generator 7 from a control panel 49 (FIG. 5) described later.

  As shown in FIG. 4, the nozzle 1 is a nozzle in which a large number of shims 27 serving as conductive members are arranged as electrodes in a slit 25 formed between a pair of nozzle blades 21 and 23 serving as a main body portion of the nozzle. A head 29 is provided. The nozzle blades 21 and 23 are made of an electrically insulating material, and the shim 27 is made of a conductive material made of a stainless steel plate having a thickness of 0.5 mm, for example.

  Further, a liquid discharge channel 31 is formed between the surface of the shim 27 and the nozzle blade 23 as a liquid channel that connects the liquid discharge port 3 and the liquid introduction port 15. The liquid discharge channel 31 is etched at a groove depth C on one surface of the shim 27, for example.

  The connector pin 17 penetrating and attached to the nozzle blade 21 is electrically connected with its inner tip in contact with the shim 27. Therefore, the high voltage generator 7 shown in FIG. 1 applies a negative DC high voltage (around −60 to −70 kv) to the shim 27 via the connector pin 17.

  While the negative potential is applied to the shim 27, the liquid introduced from the liquid inlet 15 is instantaneously charged to the negative potential by the shim 27 while passing through the liquid discharge channel 31. On the other hand, a material to be coated 33 (see FIG. 5) is disposed in front of the nozzle 1 (downward in FIG. 1A). The material to be coated 33 is grounded and has a positive potential. .

  Since liquids charged to a negative potential repel each other with the same polarity, the liquid is atomized as fine particles having a substantially uniform particle diameter, and the liquid with a reverse polarity is applied from the liquid discharge port 3 at the tip of the nozzle head 29. It is discharged toward the coating material 33 and sprayed and applied to the coating material 33 with a coating width A almost evenly.

  In addition, as shown in FIG. 2, an inductor bar 38 is attached to the lower inner walls of the left and right side walls 5 d and 5 e of the electrostatic field shielding cover 5 via a fixture 36 that can be moved up and down by a bolt 34. The inductor bar 38 can be moved in the direction perpendicular to the paper surface in FIG. Therefore, the position of the inductor bar 38 can be adjusted in the vertical direction and the direction orthogonal to the paper surface in FIG.

  Two such inductor bars 38 are provided so as to be positioned at the lower portions on both the left and right sides of the nozzle 1 in FIG. 1A, and have a weak positive potential when grounded through a high resistance. By providing the inductor bar 38, the coating width A when the liquid is sprayed as shown in FIG. 4 is adjusted. The inductor bar 38 is omitted in FIGS.

  Here, the material 33 to be applied is a top plate that is heated by placing a dough such as bread or cake, and in this embodiment, a liquid as a release oil is applied to the top plate 33 as an application liquid. . Such a material to be coated 33 is transported by, for example, a conveyor device 100 (FIG. 6) described later as a transport device, and the above-described release oil is applied during the transport.

  Moreover, in this embodiment, as shown in FIGS. 1-3, the electrostatic field shielding cover 5 which covers the nozzle 1, the high voltage generator 7 and the manifold 9 on the electrostatic field shielding cover 5, the solenoid valve 11, and the liquid supply tube 13 is covered by an outer cover 103. The outer cover 103 is made of stainless steel, for example, and surrounds the periphery of the apparatus main body 101 except for the liquid discharge port 3 side (downward in FIG. 1A), like the electrostatic field shielding cover 5. That is, the outer cover 103 includes an upper wall 103a, a front wall 103b, a rear wall 103c, and left and right side walls 103d and 103e in FIG.

  Such an outer cover 103 is grounded to ensure safety against static electricity, and also prevents the high voltage generator 7 and the manifold 9 from being exposed to the outside, thereby improving the appearance.

  As shown in FIG. 2, the electrostatic field shielding cover 5 includes a protruding portion 5a1 having an upper wall 5a protruding left and right from both side walls 5d and 5e. It protrudes to the outside through openings 103d1 and 103e1 provided in the lower part of 103e. Then, the upper end of the substantially square support plate 107 is connected to the tip of the protruding portion 5a1 via two bolts 105, and the lower end of the support plate 107 is connected to the upper end of the support stay 111 via the bolt 109. Yes.

  Near the upper end of the support plate 107, a part is bent inward (side walls 5d, 5e) to form a bent portion 107a, and the protruding portion 5a1 of the upper wall 5a is placed on and supported by the bent portion 107a. ing.

  The openings 103d1 and 103e1 formed in the side walls 103d and 103e of the outer cover 103 are substantially the same shape as the square support plate 107, and the openings 103d1 and 103e1 are covered by the support plate 107 and the upper portion of the support stay 111. Yes.

  The above-described support stay 111 has a lower end surface projecting downward from the electrostatic field shielding cover 5 and the outer cover 103, and the projecting lower end portions are provided on both sides of the conveyor apparatus 100 shown in FIG. 6. It is fixed on the mounting bracket 113 having a shape.

  The outer cover 103 is simply placed on the electrostatic field shielding cover 5 from above and fixed by fitting. Further, in this state, the fastening to the projecting portion 5a1 of one of the two bolts 105 on each of the left and right support plates 107 in FIG. 2 (one on the right side in FIG. 1A) is released. Thus, the electrostatic field shielding cover 5 and the outer cover 103 can be rotated by 90 degrees as shown in FIG.

  At this time, the length of the other end of the support bar 115 that is suspended from the upper center of the support plate 107 via the bolt 114 in the state shown in FIG. The hole 115a is fixed.

  Thereby, the opening side of the electrostatic field shielding cover 5 and the outer cover 103 is directed to the side (the right side in FIG. 1B), and in this state, the liquid discharge port 3 and the like of the nozzle 1 are cleaned. Maintenance work can be performed.

In addition, a liquid diffusion preventing member 119 is provided below the outer cover 103 to prevent the spray of liquid ejected from the nozzle 1 from diffusing. The liquid diffusion preventing member 119 has side walls that surround the four sides of the spray and penetrates in the vertical direction, and is positioned slightly outside the outer cover 103 as shown in FIGS. 1A and 2. The upper end is located slightly above the lower end of the outer cover 103. The liquid diffusion preventing member 119 is fixed to the inner surfaces of the pair of left and right support stays 111 with bolts 121 in FIG.

  Next, the liquid circuit of the electrostatic liquid coating apparatus will be described with reference to FIG. A liquid storage tank 35 that stores liquid is connected to one end of the manifold 9 by a liquid supply pipe 37, and a liquid pump 39 is disposed in the liquid supply pipe 37. The liquid pump 39 is driven by the liquid motor 41 to supply the liquid in the liquid storage tank 35 to the manifold 9 through the liquid supply pipe 37.

  The other end of the manifold 9 is connected to a liquid storage tank 35 via a liquid discharge pipe 45 having a circulation electromagnetic valve 43, and a part of the liquid supplied to the manifold 9 returns to the liquid storage tank 35. Circulate. The liquid supply pipe 37 is provided with a relief valve 47 for protecting the liquid pump 39 or the liquid circuit.

  In FIG. 5, the liquid supply pipe 37 is connected to one end of the manifold 9 and the liquid discharge pipe 45 is connected to the other end. However, as shown in FIG. And the liquid discharge piping 45 is arrange | positioned in the same direction of the right side in FIG. At this time, in FIG. 1 to FIG. 3, the piping in the outer cover 103 that connects the manifold 9 and the liquid discharge piping 45 is omitted.

  The high voltage generator 7 is controlled by a controller 51 serving as a control means provided in a control panel (operation panel) 49 to generate a high voltage.

  In the electrostatic liquid coating apparatus having such a configuration, the high voltage generator 7 controlled by the controller 51 applies a negative DC high voltage to the shim 27 via the contact pin 17 shown in FIG. The liquid motor 39 shown in FIG. 5 drives the liquid pump 39 to supply the liquid in the liquid storage tank 35 to the nozzle 1 through the manifold 9.

  In the nozzle 1, while the liquid is introduced from the liquid introduction port 15 and passes through the liquid discharge flow channel 31, the liquid is charged to a negative potential by the shim 27, and charges of the same polarity repel each other, so that the liquid is almost uniform. Atomized as fine particles of particle size. The atomized liquid jet is ejected from the liquid ejection port 3 at the tip of the nozzle head 29 toward the material to be coated 33 of opposite polarity, and sprayed and adhered to the material to be coated 33 almost uniformly. become.

  At this time, in this embodiment, the periphery of the nozzle 1 excluding the liquid discharge port 3 side (lower side in FIG. 1A) is covered with the electrostatic field shielding cover 5, so that the high voltage generator 7 forms the shim 27. Progression of the electrostatic field generated when a high voltage is applied to the outside is suppressed.

  On the other hand, in the conventional apparatus that does not use the electrostatic field shielding cover 5, the electrostatic field proceeds to the outside, so that a certain distance (for example, 40 cm to 80 cm) from the periphery of the nozzle 1 generating the high voltage. It is covered with a protective cover to prevent people from getting inside. Since this protective cover is for preventing people from approaching, the apparatus main body 101 including the nozzle 1, the high voltage generator 7, the manifold 9, and the like, like the protective cover 123 indicated by a virtual line in FIG. 6. It is necessary to charge and separate from, and it becomes extremely large. That is, the conventionally used protective cover 123 is arranged so as to straddle the left and right sides of the conveyor device 100, and is separate from the conveyor device 100.

  In this embodiment, since the progression of the electrostatic field to the outside is suppressed, the large protective cover 123 used in the above-described conventional device is not necessary, and the small outer cover 103 for mainly improving the appearance is simply covered. The size reduction is achieved to such an extent that it can be integrally attached to the conveyor device 100.

  By achieving downsizing, the weight is reduced accordingly, so handling is also improved. For example, when performing regular maintenance / inspection work, the user removes it from the conveyor device 100 and uses the courier for the manufacturer. Can be sent. Moreover, since it reduced in size, the narrow space can be utilized and the nozzle 1 can be used not only downward but also horizontally or upward as shown in FIG.

  In the present embodiment, the liquid supply tube 13 is formed in a coil shape and disposed outside the electrostatic field shielding cover 5. If the liquid supply tube 13 is too short, when a high voltage is applied, the liquid supply tube 13 may be electrically short-circuited between the nozzle 1 and the manifold 9 via a conductive liquid, in order to avoid this. A certain length is required. For example, when a liquid having an electrical conductivity of 15,000 to 200,000 PS (Pico Siemens) is used, the length of the liquid supply tube 13 is required to be 1 m or more.

  For this reason, in the present embodiment, as described above, the liquid supply tube 13 is formed in a coil shape, and the distance through which the conductive liquid flows is ensured to some extent, and compactness is also achieved. By making the liquid supply tube 13 compact, it is possible to achieve further miniaturization of the electrostatic liquid application apparatus. In the conventional device in which the liquid supply tube 13 is not formed in a coil shape but in a straight shape, the length in the vertical direction corresponding to the extending direction of the liquid supply tube 13 becomes long, leading to an increase in size of the entire device.

  In the present embodiment, the high voltage generator 7 is attached on the upper wall 5 a that is the outer wall of the electrostatic field shielding cover 5, and the manifold 9 is also attached on the upper wall 5 a adjacent to the high voltage generator 7. . On the other hand, since the electrostatic field shielding cover 5 is not used in the conventional apparatus, it is necessary to take measures such as attaching these to the above-described protective cover or the like via a dedicated attachment.

  Therefore, in this embodiment, when the high voltage generator 7 and the manifold 9 are installed, a dedicated fixture is not required unlike the conventional device, and the electrostatic field shielding cover 5 is also used as a fixture. become. For this reason, the high voltage generator 7, the manifold 9 and the nozzle 1 can be arranged in a compact manner with the electrostatic field shielding cover 5 as the center, and further downsizing of the entire apparatus can be achieved. .

In the above-described embodiment, the electrostatic field shielding cover 5 is made of polyacetal resin, but other resins may be used as long as they have a resistance value of, for example, about 10 ⁻⁷ Ωm so as to shield the electrostatic field. Alternatively, another material such as ceramic may be used.

1 Nozzle 3 Liquid outlet (Nozzle outlet)
5 Electrostatic field shielding cover (electrostatic field shielding member)
5a Electrostatic field shielding cover upper wall (outer wall of electrostatic field shielding member to which voltage application means is attached)
7 High voltage generator (voltage application means)
9 Manifold (liquid collecting part)
13 Liquid supply tube (liquid supply line)
21, 23 Nozzle blade (nozzle body)
27 Shim (conductive member)
31 Liquid discharge channel (liquid channel)
33 Top plate (material to be coated)
35 Liquid storage tank

Claims (1)

A voltage having a polarity opposite to that of the material to be coated is applied to the conductive member provided in the nozzle, and the coating liquid supplied to the liquid flow path between the main body portion of the nozzle and the conductive member is combined with the conductive member. In an electrostatic liquid coating apparatus that discharges from the nozzle outlet and adheres to the material to be coated while charging to the same polarity, when a voltage having a polarity opposite to the material to be coated is applied to the conductive member comprising an electrostatic field shielding member for shielding the electrostatic field generated,
The electrostatic field shielding member has a wall portion on the opposite side to the discharge port of the nozzle and a wall portion surrounding the side periphery of the nozzle, and corresponds to at least the discharge port on the discharge port side of the nozzle. It is provided to surround the circumference of the nozzle except for a part ,
A liquid supply line that communicates a liquid collecting portion that is supplied with a liquid from a liquid storage tank that stores the liquid and a liquid flow path of the nozzle; and the electrostatic field is formed by forming the liquid supply line in a coil shape. Placed outside the shielding member,
An electrostatic liquid coating apparatus , wherein voltage applying means for applying a voltage having a reverse polarity to the material to be coated is attached to the outer wall of the electrostatic field shielding member .

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