JPS6363263B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for electrostatically applying powder such as powder paint or synthetic resin powder continuously at high speed.

Traditionally, like washing machine and refrigerator casings,
If powder coating is applied after punching out a steel plate and forming it into the desired shape, coating bent corners and corners is troublesome and difficult, resulting in uneven coating and time consuming. There were drawbacks such as heat and poor yield.

This invention was made based on the fact that in recent years, improvements in molding, paint, and painting technology have made it possible to apply paint to a sheet punched from a steel plate and then mold it. It is something that

Therefore, the main object of the present invention is to transport flat objects to be coated at a higher speed by a conductive belt conveyor that is wider than the objects to be coated exclusively for the coating zone, in order to eliminate the above-mentioned drawbacks of the conventional art. While the object to be coated passes under the coating machine installed on the belt conveyor, only the surface of the object to be coated is coated with electrostatic powder, and the powder-coated object is transferred to the subsequent conveyor for baking. An object of the present invention is to provide an electrostatic powder coating method, which is characterized in that the powder is transferred to a paint belt to perform baking coating, and excess coating powder adhering to a coating belt conveyor is removed by suction.

Another object of the present invention is to use a conductive belt conveyor that is wider than the object to be coated and conveys the flat object to the coating zone in order to carry out the electrostatic powder coating method described above. , a coating machine installed in the coating zone to apply electrostatic powder coating to objects to be coated conveyed by the belt conveyor, and a coating machine installed on the belt conveyor to remove excess powder adhering to the coating belt conveyor. An object of the present invention is to provide an electrostatic powder coating device characterized in that it is equipped with a scraping device for scraping off excess powder, and a suction recovery device for sucking and recovering the scraped excess powder.

According to the electrostatic powder coating method and apparatus of this invention, the object to be coated can be coated not only in the form of a flat plate, but also in the form of a thin coil or a thin box with a length of 20 to 30 meters. It is stably transported to the designated coating zone at a high speed of 1/2 minute by a conductive belt conveyor, and there is no electric field concentration at the edges of the object to be coated, and the coating can be applied evenly as in the center. The adhering excess powder can be collected and reused by a scraping device and a suction recovery device.

Other objects, features and advantages of the present invention will become apparent from the following detailed description along with the accompanying drawings showing one embodiment of an apparatus for carrying out the electrostatic powder coating method of the present invention.

As shown in FIGS. 1 and 2, an electrostatic powder coating apparatus for carrying out the electrostatic powder coating method of the present invention includes a wide supply belt conveyor 2 for supplying and conveying an object 1 to be coated. and a coating belt conveyor 3, which is wider and more conductive than the object to be coated, for applying electrostatic powder coating to the supplied object to be coated in the coating zone, and A coating machine 5 disposed on the coating belt conveyor 3 to apply electric powder, a scraping device 6 for scraping excess powder adhering to the coating belt conveyor 3, and a suction device 6 for scraping off the excess powder. It mainly consists of a suction recovery device 7 for collecting, and a baking conveyor 9 provided with a baking device 8 for baking the object 1 coated with electrostatic powder. The supply belt conveyor 2 for feeding the object to be coated 1 is preferably a wide ordinary belt conveyor, but other chain conveyors or roller conveyors may also be used. In addition, this supply belt conveyor 2
is supported by a suitable support stand. The coating belt conveyor 3, which is provided adjacent to the supply belt conveyor 2 via the transfer roll 11, is wide and conductive, and is supported by a frame 15 by an appropriate support 14.
, and can be installed in any desired location. The coating machine 5 consists of a curtain booth 16 attached to a frame 15 so as to form a coating zone, and a curtain booth 16 is provided inside the curtain booth 16 for electrostatically coating the object 1 to be coated carried by the belt conveyor 3. A plurality of electrostatic guns 17 are provided. These electrostatic guns 17 are supported by a reciprocator 18 provided at the top of the curtain booth 16 so that they can reciprocate in a direction perpendicular to the conveying direction of the belt conveyor 3. In addition, recovery ducts 21 and 22 are provided at the entrance and exit sides of the curtain booth 16, and recovery cyclones 23 and 24 are attached to the ends of these recovery ducts 21 and 22, and the recovery cyclones 23 and 24 are installed from the top of the coating machine 5. The air supplied into the curtain booth 16 is
6 Flowing along the inner surface and collecting cyclones 23, 24
By being absorbed by the curtain booth 1
A part of the excess powder during electrostatic coating inside the curtain booth 16 can be recovered, and it is also possible to prevent the powder from being applied inside the curtain booth 16. Furthermore, a scraping device 6 is provided on the return side of the coating belt conveyor 3 to scrape and collect excess powder adhering to the belt conveyor. This scraping device 6 includes a scraping blade 25 that scrapes off powder adhering to the conveyor.
The powder covered and scraped off by the suction hood 27 of the recovery device 7 can be recovered via the recovery cyclone 28 of the recovery device 7. Furthermore, such a scraping device can be provided not only on the return side of the conveyor, but also at an appropriate location on the supply side, that is, on the top surface side.

The powder collected by the collection cyclone 28 of the collection device 7 is mixed with new powder and reused for electrostatic coating.

The object 1 to be coated, the surface of which has been coated with electrostatic powder, is transferred to a baking conveyor 9 via another transfer roll 12.
The powder is then baked as it passes through a baking device 8 consisting of a baking oven, such as an infrared oven.

The curtain booth 16 is made of a soft film such as vinyl or nylon into a roof shape as shown in the figure, and is supported by a support bracket 32 with a set bolt 31 near the top, and a collection duct 21, By attaching it to 22, it can be assembled into the desired shape as shown, and the color of the powder can be changed by preparing each color of powder or by preparing at least two or more curtain booths in advance. The work can be done easily and in a short time, and efficiency can be improved.

As described above, according to the electrostatic powder coating method and apparatus of the present invention, flat, thin box-shaped, and coil-shaped objects to be coated are conveyed to the coating zone by a belt conveyor and electrostatically coated. Can be transported at high speed and stably,
Since the workpiece placed on a conductive coating belt conveyor is electrostatically coated in the coating zone, there is no concentration of electric field at both edges of the workpiece, and the electric field is uniform over the entire surface of the workpiece as well as the center. The powder coating can be applied to a certain thickness, and the coating film can be applied to the minimum thickness, saving powder coating, and there is no coating on the back side of the object to be coated. In addition, since the painting belt conveyor is used exclusively for painting, excess powder adhering to the belt can be scraped off by a scraping device and collected by a collection device for reuse. A collection duct can be installed on the entrance/exit side to collect excess powder inside the curtain booth, and the curtain booth, collection cyclone, collection duct, and collection device, which are preferably built in one piece, are prepared for each paint color. By replacing the belt conveyor as appropriate, all you have to do is clean the belt conveyor, and the replacement work can be done easily and in a short time.
Loading and unloading can be automated without the need for any special transport jig. In particular, since the object to be coated has a flat plate shape or a thin box shape close to a flat plate shape, a uniform minimum coating thickness can be ensured, and powder paint can be saved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of an apparatus for carrying out the electrostatic powder coating method of the present invention, and FIG. 2 is a perspective view of the coating machine portion of this electrostatic powder coating apparatus. . In the figure, 1... object to be coated, 2... belt conveyor for supply, 3... belt conveyor for painting, 5...
... Painting machine, 6 ... Scraping device, 7 ... Suction recovery device, 8 ... Baking device, 9 ... Conveyor for baking,
16... Curtain booth, 17... Electrostatic gun, 1
8... Reciprocator, 21, 22... Recovery duct, 23, 24... Recovery cyclone, 25... Scraping blade, 28... Recovery cyclone.

Claims (1)

[Scope of Claims] 1. A coating machine in which a flat object to be coated is conveyed by a conductive belt conveyor that is wider than the object to be coated exclusively for a coating zone, and the object to be coated is provided in the coating zone of the belt conveyor. Only the surface of the object to be coated is electrostatically powder-coated while passing under the surface, and then the powder-coated object is conveyed to a baking furnace by a subsequent baking conveyor, where it is baked and painted. An electrostatic powder coating method characterized by suctioning and removing excess powder adhering to a coating belt conveyor. 2. A belt conveyor that is wider and more conductive than the object to be coated that conveys the flat plate-shaped object to the coating zone, and a belt conveyor that is wider and more conductive than the object to be coated that conveys the flat object to be coated to the coating zone, and is installed in the coating zone to apply electrostatic powder coating to the object to be coated that is conveyed by the belt conveyor. a coating machine, a scraping device provided on the belt conveyor to remove excess powder adhering to the belt conveyor, and a suction recovery device to suction and recover the scraped excess powder. Characteristic electrostatic powder coating equipment. 3. The coating machine has a curtain booth attached to the coating belt conveyor so as to form a coating zone on the coating belt conveyor, and an electrostatic gun supported reciprocatingly on the upper part of the curtain booth. 3. The electrostatic powder coating apparatus according to claim 2, wherein excess powder in the curtain booth can be recovered through a recovery duct provided at the lowest end entrance/exit side of the booth.