JP3774742B2 - Electrostatic powder coating device for inner surface of can body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrostatic powder coating apparatus for an inner surface of a can body that performs electrostatic coating of a powder coating on the inner surface of the can body.
[0002]
[Prior art]
For beverage cans and aerosol cans, a metal plate with coating printing on the inner and outer surfaces is rolled into a cylindrical shape and welded at both ends to form a can body, and then a weld seam is corrected and applied, A so-called three-piece can in which a canopy and a bottom lid are wound around both ends of the can body is used. In this type of can body, the inner surface of the can body is painted with a solvent-based paint in order to protect the contents inside and prevent corrosion due to the contents, and the weld seam is also subjected to correction painting in the same manner.
[0003]
By the way, especially for can bodies filled with highly corrosive contents, it is necessary to apply a relatively thick coating to the inner surface of the can body. It is difficult to form. In addition, when a solvent-based paint is used, the environment during the painting work may be deteriorated. Therefore, in recent years, it has been considered to perform electrostatic powder coating capable of thick coating using a solvent-free powder coating. When electrostatic powder coating is applied to the inner surface of the can body, the can body is grounded, and the powder coating charged from one opening end of the can body is sprayed toward the inner surface of the can body, and the electrostatic effect is applied to the powder. Apply body paint to the inner surface of the can body.
[0004]
[Problems to be solved by the invention]
However, when applying such electrostatic powder coating, since the powder coating is sprayed from one open end toward the inner surface of the can body with both ends of the can body open, the sprayed powder coating May flow out from the other opening end and it may be difficult to uniformly apply the powder coating along the inner surface of the can body.
[0005]
In particular, when one of the opening ends of the can body is reduced in diameter like a neck-in can, the powder coating must be sprayed concentrated on the inclined inner surface of the reduced diameter portion. Then, there is a disadvantage that the coating film on the other part of the inner surface of the can body becomes thin.
[0006]
In order to eliminate such inconvenience, the present invention can uniformly form a relatively thick coating film on the inner surface of the can body, and can efficiently coat the inner surface of the can body. An object is to provide an apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the present invention is an electrostatic powder coating apparatus for an inner surface of a can body that performs electrostatic coating of a powder coating on the inner surface of a cylindrical can body that is open at both ends. Loading means, conveying means for rotatably holding the can body charged from the charging means and stopping it at every predetermined distance, and at the stop position of the can body conveyed by the conveying means, the can body A first powder coating stage for applying a powder coating mainly to a region on one end opening side of the inner surface, and a stop position of the can body transported from the first powder coating stage by the transport means; A second powder coating stage for applying a powder coating mainly to a region on the other end opening side of the inner surface of the can body, and the can body transported from the second powder coating stage by the transport means; The can body is received and discharged from the conveying means at the stop position. Means, and the first powder coating stage has a can body rotating means for rotating the can body around its axis, and the can body from the opening facing the one end opening of the can body. A spraying means for spraying the powder coating toward the region of the inner surface mainly on the one end opening side, and facing the other end opening of the can body and sucking air from the opening to form an air flow inside the can body An intake means, and the second powder coating stage has a can cylinder rotating means for rotating the can cylinder about its axis and an opening at the other end of the can cylinder. A spraying means for spraying the powder coating mainly toward the region on the other end opening side of the inner surface of the can body, facing one end opening of the can body, sucking air from the opening, and causing an air flow inside the can body And an intake means to be formed.
[0008]
According to the present invention, the can body charged by the charging means is transferred by the transfer means. The transport means stops the can body every time the can body is transported by a predetermined distance. Each stage is provided at each stop position of the can body by the conveying means. As a result, first, a powder coating is applied mainly to a region on one end opening side of the inner surface of the can body in the first powder coating stage, and then the can is formed in the second powder coating stage. A powder coating material is applied mainly to the region of the inner surface of the body on the side of the opening at the other end.
[0009]
More specifically, first, the can body stopped by the conveying means on the first powder coating stage is rotated by a can body rotating means provided on the stage. At this time, the powder coating material is ejected from the ejection means facing the one end opening of the can body mainly toward the region on the one end opening side of the inner surface of the can body. The powder coating material ejected from the ejection means is attracted to the inner surface of the grounded can body by charging, whereby the powder coating material is applied to the inner surface of the can body. At this time, an air flow is formed inside the can body by being sucked by the intake means from the other end opening side of the can body, and the can body is rotated by the can body rotating means. Thus, the powder coating can be uniformly applied in the region on the one end opening side. In addition, since the powder coating is intensively ejected toward the region on the one end opening side of the can body by the ejection means, the powder coating can be applied relatively thickly on the region on the one end opening side. it can.
[0010]
Next, the can body which has been transported by the transport means from the first powder coating stage and stopped at the second powder coating stage is rotated by a can body rotating means provided in the stage. At this time, the powder paint is ejected from the ejection means facing the other end opening of the can body mainly toward the region on the other end opening side of the inner surface of the can body. The powder coating material ejected from the ejection means is charged, and the powder coating material is applied to the inner surface of the can body when the can body is grounded. Then, air is sucked from the one end opening side of the can body by the air suction means. In the second powder coating stage, the powder coating material is jetted mainly by the jetting means toward the other end opening side region of the can body.
[0011]
As described above, the inner surface of the can body is divided into two regions of the one end opening side and the other end opening side, and the region on the one end opening side is mainly coated by the first powder coating stage. Since the powder coating stage mainly coats the area on the opening side of the other end, the coating area by each stage can be reduced, the painting operation can be performed quickly, and the entire inner surface of the can body can be coated relatively thick and uniformly. it can. Thereby, when the welding seam is formed in the can body, it can serve as correction | amendment coating of the part.
[0012]
In addition, since the painting operation on the inner surface of the can body at each stage is performed while being intermittently conveyed by the conveying means, the painting operation can be continuously performed on a plurality of can bodies and efficiently in a short time. Can be painted.
[0013]
Further, in the present invention, the powder coating material is applied mainly to the central region of the inner surface of the can body at the stop position of the can body transported by the transport means between the charging means and the first powder coating stage. There is provided another powder coating stage to be applied, the powder coating stage facing a can cylinder rotating means for rotating the can cylinder about its axis and an opening of one of the can cylinders. And a spraying means for spraying a charged powder coating mainly from the opening toward the central region of the inner surface of the can body, and the other opening portion of the can body facing the other opening and sucking air from the opening, Intake means for forming an air flow is provided.
[0014]
According to this, prior to the first powder coating stage, the inner surface of the can body can be coated mainly by the other powder coating stage mainly on the central region, and the can body length is relatively long. It is suitable in some cases. That is, first, the can body stopped at the other powder coating stage by the conveying means is coated with the powder coating material ejected from the ejecting means while being rotated by the can body rotating means. At this time, the powder coating is applied mainly to the central region of the inner surface of the can body by riding on the airflow generated by the intake means. In this way, the inner surface of the can body is divided into a central region, one end opening side region, and the other end opening side region, and each region is coated separately, so even if the can body length is relatively long, each stage The coating area can be reduced, the coating operation can be performed quickly, and the entire inner surface of the can body can be uniformly coated with a desired thickness.
[0015]
Further, in the present invention, the discharge means includes a transfer means for transferring the can body to a heating means for baking the powder coating material applied to the inner surface of the can body in each stage. It is preferable to provide an adsorbing means for adsorbing and holding the peripheral wall from above, and to transfer the can body to the heating means while adsorbed by the adsorbing means.
[0016]
The discharging means transports the can body having the powder coating on the inner surface in the adsorbed state by the adsorbing means, so that vibration or collision with other can bodies can occur without causing inadvertent movement in the can body. It is possible to prevent the powder paint applied to the inner surface of the can body from being peeled off, and it can be transferred to the heating means at a high speed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of the present embodiment apparatus, FIG. 2 is an explanatory diagram showing a powder coating process in each stage, and FIG. 3 is an explanatory diagram showing a powder coating process on another can body. 4 is an explanatory view showing the discharging means.
[0018]
This implementation apparatus 1 has an upper end opening X that is closed by tightening the canopy and the bottom lid. ₁ And lower end opening X ₂ Powder coating is performed on the inner surface of the cylindrical can body W on which the and are formed. The can body W has an upper end opening X as shown in FIGS. ₁ Neck-in part X with reduced diameter _Three Due to the lower end opening X ₂ It has a smaller diameter.
[0019]
In FIG. 1, reference numeral 2 denotes an input means for supplying a can body W, 3 denotes a transport means for transporting the can body W input by the input means 2 along a circumference, and 4 denotes a can transported by the transport means 3. A central powder coating stage 5 for applying a powder coating mainly on the inner surface of the inner surface of the cylinder W, 5 is a can cylinder conveyed by the conveying means 3 on the downstream side of the central powder coating stage 4. A lower end powder coating stage for applying a powder coating mainly to a lower end side region of the inner surface of W, 6 is a can transported by the transport means 3 on the downstream side of the lower end powder coating stage 5 An upper end powder coating stage for applying a powder coating mainly to an upper end side region of the inner surface of the barrel W, and 7 is a discharge means for discharging the can barrel W downstream of the upper end powder coating stage 6. It is. 4 is a phantom line, 8 is a heating means for baking the powder coating material applied to the inner surface of the can body W.
[0020]
As shown in FIG. 1, the transport means 3 includes a turntable 11 that is rotatably supported by a gantry 10 that stands on a base 9, and that holds the can body W and transports it circumferentially. . The turntable 11 includes a plurality of can barrel holding portions 12 formed in an arc shape with a predetermined interval at a peripheral portion thereof, and the can barrel holding portion 12 has a plurality of supports that are rotatable on an inner periphery thereof. A roller 13 is provided. Accordingly, the can body W is held by the can body holding portion 12 via the support roller 13 and is held by the support roller 13 so as to be rotatable about the axis of the can body W. The rotating disk 11 rotates while being stopped for a predetermined time at predetermined angles by a drive motor (not shown). In addition, although not shown in figure, this conveyance means 3 hold | maintains in the said can body holding | maintenance part 12 in the state which earth | grounded the can body W.
[0021]
In addition, the transport means 3 includes a plurality of guide members 14 for abutting and guiding the can body W from the outside in order to guide the can body W along the transport path of the can body W with high accuracy.
[0022]
As shown in FIG. 1, the charging means 2 loads the can body W into the can body holding portion 12 when one of the can body holding portions 12 of the rotating disk 11 is stopped at the loading position. The feeding means 2 is connected to the gantry 10 and continuously guides a plurality of can bodies W toward the feeding position of the transport means 3, and each can body guided by the guide member 15. And a delivery member 16 for delivering W at a predetermined interval. The delivery member 16 extends in the feeding direction of the can body W of the can body, is rotatably supported by the frame 17, and is rotationally driven by a drive motor (not shown) via the rotation shaft 18. The delivery member 16 has a spiral locking groove 19 formed in the peripheral wall thereof, and each can body W can be locked in the locking groove 19. By rotating the delivery member 16, the can body W locked in the locking groove 19 is moved in the loading direction. Furthermore, the locking groove 19 is formed in a shape in which the pitch gradually increases from the upstream side toward the downstream side. As a result, each can body W guided by the guide member 15 is widened by the rotation of the delivery member 16 so that the interval between adjacent ones increases as the feeding direction approaches, and the turntable 11 rotates intermittently. Thus, the can body W can be loaded into the can body holding portion 12 positioned at the loading position in time.
[0023]
As shown in FIG. 1, the center part powder coating stage 4 is held by the can body holding part 12 at a stop position of the can body holding part 12 of the rotating disk 11 on the downstream side of the charging position. A can body rotating means 20 for rotating the can body W is provided. The can barrel rotating means 20 is provided on a support member 21 fixed to the gantry 10, and a belt 22 that rotates endlessly by contacting the outward path side to the outside of the can barrel W held by the can barrel holding portion 12. A pair of pulleys 23 around which the belt 22 is stretched, a drive pulley 24 over which the return path side of the belt 22 is stretched, and a drive motor (not shown) that drives the rotation of the belt 22 via the drive pulley 24. It is configured. Although not shown in FIG. 1 for convenience of explanation, as shown in FIG. 2A, the center part powder coating stage 4 is formed of the can body W held by the can body holding portion 12. Upper end opening X ₁ A spraying means 25 for spraying the powder paint Y from the side toward the inside of the can body W, and a lower end opening X of the can body W facing the spraying means 25 ₂ Intake means 26 that intakes air from the side and forms an air flow inside the can body W is provided. Referring to FIG. 1, in the central powder coating stage 4, a jetting means 25 is provided on the back side (back side of the paper surface) of the gantry 10 through an open part 27 formed through the front and back surfaces of the gantry 10. The intake means 26 (shown in phantom lines in FIG. 1) is arranged on the front side (the front side of the drawing) of the gantry 10.
[0024]
As shown in FIG. 2A, the ejection means 25 is constituted by a spray nozzle 28 and a supply device (not shown) that supplies the powder paint Y charged to the spray nozzle 28. The spray nozzle 28 has a cylindrical outer shape, the inner diameter is gradually reduced from the center toward the tip, and the outer diameter of the tip is the upper end opening X of the can body W. ₁ It is formed smaller than the inner diameter. The tip of the spray nozzle 28 and the upper end opening X of the can body W ₁ Are opposed to each other with a slight gap. The intake means 26 includes an intake duct 29 and an intake device (not shown) that is connected to the intake duct 29 and intakes air from the intake duct 29.
[0025]
In the central powder coating stage 4, first, the charged powder coating Y is sprayed from the spray nozzle 28 toward the inner surface of the can body W. At the same time, the upper end opening X of the can body W is sucked by the intake duct 29 ₁ The air flows into the inside from the bottom opening X ₂ An airflow toward the inside is formed inside the can body W. As a result, the powder coating Y ejected from the spray nozzle 28 is placed on the central area W of the inner surface of the can body W along the airflow. ₁ Mainly the central region W is diffused in the vicinity and the can body W is grounded. ₁ Apply to. At this time, since the can body W is rotated by the can body rotating means 20, the powder coating Y is uniformly applied to the inner surface of the can body W. The excess powder paint Y is sucked into the intake duct 29 by the air flow inside the can body W and collected.
[0026]
Although not shown, the spray nozzle 28 of the ejection means 25 and the intake duct 29 of the intake means 26 are provided so as to be able to advance and retreat toward the can body W, respectively. As a result, even if the can body has different length dimensions, the spray nozzle 28 and the intake duct 29 can be positioned at a position suitable for the can body. Further, in the central part powder coating stage 4 of the present embodiment 1, the spray nozzle 28 is connected to the upper end opening X. ₁ The intake duct 29 faces the lower end opening X. ₂ On the contrary, the intake duct 29 is arranged so as to face the lower end opening X. ₂ The spray nozzle 28 at the top opening X ₁ It may be arranged to face.
[0027]
As shown in FIG. 1, the lower end powder coating stage 5 is provided at a stop position of the can body W by the conveying means 3 on the downstream side of the central powder coating stage 4. The lower end powder coating stage 5 includes a can body rotating means 30 for rotating the can body W held by the can body holding section 12 having the same configuration as that of the central portion powder coating stage 4, and FIG. As shown in (b), the lower end opening X of the can body W held by the can body holding portion 12 ₂ Jetting means 31 for jetting powder paint from the side toward the inside of the can body W, and an upper end opening X of the can body W facing the jet means 31 ₁ Intake means 32 that intakes air from the side and forms an air flow inside the can body W is provided. Referring to FIG. 1, in the powder coating stage 5 at the lower end portion, a jetting means 31 is provided on the front side (the front side of the paper surface) of the gantry 10 through an open portion 27 formed through the front and back surfaces of the gantry 10. The suction means 32 (shown in phantom lines in FIG. 1) is arranged on the back side (back side of the paper) of the gantry 10. The can barrel rotating means 30 has the same configuration as the can barrel rotating means 20 of the central powder coating stage 4 described above, and therefore, the same reference numerals are used in the drawing and description thereof is omitted.
[0028]
As shown in FIG. 2B, the ejection means 31 of the lower end powder coating stage 5 supplies a spray nozzle 34 with a hood 33 attached to the tip, and a charged powder paint to the spray nozzle 34. It is comprised with the supply apparatus which is not shown in figure. The spray nozzle 34 has a cylindrical outer shape, and the inner diameter gradually increases from the vicinity of the center toward the tip. The inner diameter of the hood 33 attached to the tip of the spray nozzle 34 is rapidly expanded at the tip, and the inner diameter of the tip of the hood 33 is the lower end opening X of the can body W. ₂ The outer diameter is slightly larger than the outer diameter. Lower end opening X of can body W ₂ There is a slight gap between the hood 33 and the tip of the hood 33. The intake means 32 includes an intake duct 35 and an intake device (not shown) that is connected to the intake duct 35 and intakes air from the intake duct 35. Although not shown, the spray nozzle 34 of the ejection means 31 and the intake duct 35 of the intake means 32 can be moved forward and backward toward the can body W, respectively, as in the case of the central powder coating stage 4. Is provided. As a result, even if the can body has different length dimensions, the spray nozzle 34 and the intake duct 35 can be positioned at a position suitable for the can body.
[0029]
In the lower end powder coating stage 5, first, the charged powder coating Y is sprayed from the spray nozzle 34 toward the inner surface of the can body W. At the same time, the upper end opening X of the can body W is sucked by the intake duct 35 ₁ The air flows into the inside from the bottom opening X ₂ An airflow toward the inside is formed inside the can body W. At this time, the air flowing into the can body W is the lower end opening X ₂ A small amount flows in the radial direction of the can body W from the gap between the hood 33 and the hood 33, and the air flow in the can body W becomes relatively weak. As a result, the powder paint Y ejected from the spray nozzle 34 is applied to the lower end opening X. ₂ The lower end opening X of the inner surface of the can body W is mainly diffused by the side and the can body W is grounded. ₂ Area W ₂ Apply to. At this time, since the can body W is rotated by the can body rotating means 30, the powder coating Y is uniformly applied to the inner surface of the can body W. The excess powder paint Y is sucked into the intake duct 35 by the air current inside the can body W and collected. Further, the inner diameter of the hood 33 is the lower end opening X ₂ Because the diameter is slightly larger than the outer diameter of the ₂ Flows into the inside of the can body W while being wound inside. As a result, the powder coating Y is prevented from scattering toward the outer surface of the can body W, and the powder coating Y has a lower end opening X. ₂ It is also applied to the edges.
[0030]
As shown in FIG. 1, the upper end powder coating stage 6 is provided at a stop position of the can body W by the conveying means 3 on the downstream side of the lower end powder coating stage 5. The upper end powder coating stage 6 includes a can body rotating means 36 for rotating the can body W held by the can body holding portion 12 having the same configuration as that of the central portion powder coating stage 4. FIG. As shown in (c), the upper end opening X of the can body W held by the can body holding portion 12 ₁ A spraying means 37 for spraying the powder paint from the side toward the inside of the can body W, and a lower end opening X of the can body W facing the spraying means 37 ₂ Intake means 38 that intakes air from the side and forms an air flow inside the can body W is provided. Referring to FIG. 1, in the upper end powder coating stage 6, an ejection means 37 is provided on the back side (the back side of the paper surface) of the gantry 10 through an open portion 27 formed through the front and back surfaces of the gantry 10. The intake means 38 (shown in phantom lines in FIG. 1) is arranged on the front side (the front side of the drawing) of the gantry 10. The can barrel rotating means 36 has the same configuration as the can barrel rotating means 20 of the central powder coating stage 4 described above, and therefore, the same reference numerals are given in the drawing and description thereof is omitted.
[0031]
As shown in FIG. 2C, the ejection means 37 of the upper end powder coating stage 6 supplies a spray nozzle 40 with a hood 39 attached to the tip, and a charged powder coating material to the spray nozzle 40. It is comprised with the supply apparatus which is not shown in figure. The spray nozzle 40 has a cylindrical outer shape, and the inner diameter gradually increases from the vicinity of the center toward the tip. The inner diameter of the hood 39 attached to the tip of the spray nozzle 40 is further enlarged at the tip, and the inner diameter of the tip of the hood 39 is the upper end opening X of the can body W. ₁ The outer diameter is slightly larger than the outer diameter. Upper end opening X of can body W ₁ There is a slight gap between the hood 39 and the tip of the hood 39. The intake means 38 includes an intake duct 41 and an intake device (not shown) that is connected to the intake duct 41 and intakes air from the intake duct 41. Although not shown, the upper end powder coating stage 6 also has a spray nozzle 40 of the ejection means 37 and an intake duct 41 of the intake means 38 in the same manner as the central powder coating stage 4. It is provided so as to be able to advance and retreat toward the can body W. As a result, even if the can body has different length dimensions, the spray nozzle 40 and the intake duct 41 can be positioned at a position suitable for the can body.
[0032]
In the upper end powder coating stage 6, as shown in FIG. 2C, first, the charged powder paint Y is sprayed from the spray nozzle 40 toward the inner surface of the can body W. At the same time, air is sucked in by the intake duct 41 and the upper end opening X of the can body W ₁ From the inside to the inside, and the upper end opening X ₁ An airflow toward the inside is formed inside the can body W. At this time, the air flowing into the can body W ₁ A small amount flows in the radial direction of the can body W from the gap between the hood 39 and the hood 39, and the air flow in the can body W becomes relatively weak. As a result, the powder paint Y ejected from the spray nozzle 40 is applied to the upper end opening X. ₁ The upper end opening X on the inner surface of the can body W is mainly diffused by the side and the can body W is grounded. ₁ Area W _Three Apply to. At this time, since the can body W is rotated by the can body rotating means 36, the powder coating Y is uniformly applied to the inner surface of the can body W. The excess powder paint Y is sucked into the intake duct 41 and collected by the airflow inside the can body W. Further, the inner diameter of the hood 39 is the upper end opening X. ₁ The air is slightly larger than the outer diameter of the ₁ Flows into the inside of the can body W while being wound inside. As a result, the powder coating Y is prevented from scattering in the outer surface direction of the can body W, and the powder coating Y has an upper end opening X. ₁ It is also applied to the edges.
[0033]
As described above, the present embodiment 1 uses the center powder coating stage 4, the lower end powder coating stage 5, and the upper end powder coating stage 6 while transporting the can body W by the transport means 3. The powder coating is sequentially applied to the inner surface of the can body W. As a result, as shown in FIGS. 2A to 2C, the inner surface of the can body W first has its central region W. ₁ Is then powder coated, then the lower end opening X ₂ Area W ₂ Is powder coated, and then the top opening X ₁ Area W _Three Is powder coated and the entire inner surface of the can body W is painted. In this way, the inner surface of the can body W ₁ , W ₂ , W _Three Each region W ₁ , W ₂ , W _Three Is uniformly applied to a desired film thickness, and the entire inner surface of the can body W can be easily applied relatively thickly and uniformly.
[0034]
In addition, this implementation apparatus 1 has upper end opening X ₁ Neck-in part X _Three The upper end opening X is formed by forming ₁ Is the lower end opening X ₂ It has a structure suitable for applying powder coating to the inner surface of the can body W formed with a smaller diameter. That is, according to the present embodiment 1, the lower end opening X on the inner surface of the can body W is caused by the lower end powder coating stage 5. ₂ The upper end opening X is applied by the upper end powder coating stage 6 after powder-coating the side region. ₁ Powder coating the side area. For example, when this order is reversed and the upper end powder coating stage 6 is provided on the upstream side of the lower end powder coating stage 5, the powder coating in the lower end powder coating stage 5 is performed. The upper end opening X on the intake side ₁ Is reduced in diameter, the flow of air and powder coating becomes stronger, and the upper end opening X in the upper end powder coating stage 6 is first formed. ₁ Area W _Three There is a possibility that the powder coating applied to the film peels off and is sucked, and the coating film becomes thin. This implementation apparatus 1 has an upper end opening X ₁ Area W _Three Powder coating on the bottom opening X ₂ Area W ₂ This is prevented by performing the process after the powder coating. By the way, according to the embodiment 1, the upper end opening X ₁ And lower end opening X ₂ Even if the can body is formed to have the same diameter, it is possible to easily coat the inner surface relatively thickly and uniformly. In this case, although not shown, since the upper end opening is not reduced in diameter, the air flow or the powder coating does not flow, and the upper end powder coating stage 6 is replaced with the lower end powder coating stage. 5 may be provided on the upstream side.
[0035]
Further, according to the present embodiment 1, as shown in FIGS. 3 (a) and 3 (b), the inner surface of the can body W is shorter than that of the can body W (shown in FIG. 2). It is easy to paint thick and uniform. In this case, it is not necessary to perform the powder coating on the central region by the central powder coating stage 4, and as shown in FIG. Lower half region W of trunk W ₂ Then, as shown in FIG. 3 (b), the upper half region W of the can body W in the upper end powder coating stage 6 is applied. _Three It is sufficient to apply a powder coating. Therefore, when the inner surface coating is performed on the can body W having a relatively short can body length as described above, the central powder coating stage 4 in the embodiment 1 may not be provided, although not shown.
[0036]
Furthermore, according to the present embodiment 1, since the spray nozzles 28, 34, 40 of the ejection means 25, 31, 37 provided on the respective stages 4, 5, 6 are arranged outside the can body W, Conventionally, it can also be applied to small-diameter cans in which it is difficult to dispose a coating nozzle inside the can body W. That is, generally, the welding can body has to be coated with a corrected seam. Conventionally, although not shown, a coating nozzle is disposed inside the can body, and the welding seam is corrected and coated with this nozzle. Therefore, the welded can body which can be manufactured was limited to a thing larger than the can body diameter which can arrange | position a coating nozzle. However, according to the present invention, the powder coating can be ejected from the outside of the can body W to be applied to the inner surface of the can body W, and the inner surface of the can body W can also be corrected. There is an effect that it can be applied to a small-diameter can that is difficult to arrange inside.
[0037]
As shown in FIG. 1, the discharge means 7 is provided at a stop position of the can body W by the transport means 3 on the downstream side of the upper end powder coating stage 6. As shown in FIGS. 1 and 4, the discharge means 7 is rotatably supported on the gantry 10, and is held by the can body holding portion 12 of the transport means 3 at the stop position of the can body W. A turret 43 having a plurality of can barrel locking portions 42 on the outer periphery thereof, and a can barrel W held by the turret 43 and separated from the can barrel holding portion 12 of the conveying means 3 from the turret 43 It is comprised by the transfer conveyor 44 transferred toward the heating means 8. FIG. As shown in FIG. 4, the transfer conveyor 44 extends in the axial direction of the can body W held by the turret 43. Although not shown in detail, the heating means 8 is for baking the powder coating material applied to the inner surface of the can body W in each of the stages 4, 5, 6.
[0038]
The turret 43 is intermittently rotated in synchronism with the turntable 11 of the transport means 3 by driving of a drive motor (not shown). Although not shown, the can barrel locking portion 42 of the turret 43 is provided with a suction hole, and the side surface of the can barrel W can be sucked and held by suction means connected to the suction hole. ing.
[0039]
As shown in FIG. 4, the transfer conveyor 44 includes a pair of driven pulleys 45 coaxially provided at a predetermined interval on the upstream side and a pair of coaxial pulleys provided at a predetermined interval on the downstream side. A drive pulley 46, a pair of endless conveyor belts 47 stretched between the pulleys 45 and 46, and a drive motor (not shown) that drives the drive pulley 46 are provided. The conveyor belt 47 is rotated in the transfer direction of the can body W with the lower side as an outward path. Further, a magnet 48 is provided along the direction of transfer of the can body W on the forward path side of the transport belt 47, and the can body W can be attracted and held on the transport belt 47 from above by the magnetic force of the magnet.
[0040]
The transfer conveyor 44 can prevent vibrations and collisions with other can bodies W without inadvertently moving the can body W, so that the powder coating applied to the inner surface of the can body W can be peeled off. The can body W can be transferred to the heating means 8 at a higher speed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic configuration of an apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory view showing a powder coating process in each stage.
FIG. 3 is an explanatory view showing a powder coating process on another can body.
FIG. 4 is an explanatory view showing discharge means.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Implementation apparatus (electrostatic powder coating apparatus), 2 ... Input means, 3 ... Conveyance means, 4 ... Center part powder application stage (other powder application stages), 5 ... Lower end part powder application stage ( (First powder coating stage), 6 ... upper end powder coating stage (second powder coating stage), 7 ... discharging means, 8 ... heating means, 20, 30, 36 ... can barrel rotating means, 25, 31, 37 ... ejecting means, 26, 32, 38 ... intake means, 44 ... transfer conveyor (transfer means), 48 ... magnet (adsorption means).

Claims (3)

An electrostatic powder coating device for the inner surface of a can body that performs electrostatic coating of powder coating on the inner surface of a cylindrical can body that is open at both ends,
A charging means for charging the can body;
A transporting means for transporting the can body, which is thrown from the throwing means, while being rotatably held and stopped at every predetermined distance;
A first powder coating stage for applying a powder coating mainly to a region on the one end opening side of the inner surface of the can body at a stop position of the can body transported by the transport means;
A second powder coating for applying a powder coating mainly to a region on the other end opening side of the inner surface of the can body at the stop position of the can body transported from the first powder coating stage by the transport means. The arrival stage,
A discharge means for receiving and discharging the can body from the transfer means at a stop position of the can body transferred from the second powder coating stage by the transfer means;
The first powder coating stage has a can cylinder rotating means for rotating the can cylinder about its axis, and one end opening mainly on the inner surface of the can cylinder from the opening facing the one end opening of the can cylinder. There are provided spraying means for spraying the powder paint toward the region on the side, and suction means for facing the other end opening of the can body and sucking air from the opening to form an air flow inside the can body ,
The second powder coating stage has a can barrel rotating means for rotating the can barrel around its axis, and the other end of the can barrel facing the other end opening of the can barrel. There are provided jetting means for jetting the powder paint toward the region on the opening side, and suction means for sucking air from the opening facing one end opening of the can body and forming an air flow inside the can body An electrostatic powder coating apparatus for the inner surface of a can body characterized by being made. Other powder for applying a powder coating mainly to the central area of the inner surface of the can body at the stop position of the can body conveyed by the conveying means between the charging means and the first powder coating stage There is a painting stage,
The powder coating stage includes a can cylinder rotating means for rotating the can cylinder about its axis, and faces one of the openings of the can cylinder from the opening to a central region on the inner surface of the can cylinder. An ejection means for ejecting the powder coating toward the other side, and an intake means for facing the other opening of the can body and sucking air from the opening to form an air flow inside the can body 2. The electrostatic powder coating apparatus for an inner surface of a can body according to claim 1, wherein The discharge means includes a transfer means for transferring the can body to a heating means for baking the powder coating material applied to the inner surface of the can body in each stage.
3. The transfer device according to claim 1, wherein the transfer unit includes an adsorption unit that adsorbs and holds the peripheral wall of the can body from above, and the can body is transferred to the heating unit while being adsorbed by the adsorption unit. Electrostatic powder coating device for the inner surface of the can body.

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