JP3108818B2 - Apparatus for printing and / or printing coil metal sheet and baking hardening method using the apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a baking apparatus for continuously drying and baking a coil metal plate used as a material for cans, for example, after coating and / or printing, and using the apparatus. Paint on the coiled metal plate or /
And a method for baking and curing a printing ink.

[0002]

2. Description of the Related Art A long thin sheet metal such as iron or aluminum is wound in a coil shape, and is used as a so-called coil metal sheet, for example, as a material for can making. The coil metal plate set on the uncoiler is transported while being unraveled by the transport drive device and proceeds, and the surface is continuously painted, printed with patterns, characters, etc., then dried, baked and cured Then, this is cut into a predetermined size.

Conventionally, a hot-air drying furnace has been used to continuously heat the coil metal plate during the drying. That is, the coated coil metal plate is heated by passing through a tunnel-type hot-air drying furnace whose temperature is maintained within a predetermined temperature range, and drying and baking hardening of the paint and the like are completed. In heating using this hot air drying oven,
After the temperature in the drying furnace rises due to the hot air, the temperature of the coil metal plate rises due to the warming by the atmosphere, so that it takes some time until the temperature of the coil metal plate reaches a predetermined temperature. Therefore, it is necessary to pass through a hot air drying furnace for a certain period of time. However, there is a limit to reducing the traveling speed of the coil metal plate in order to maintain consistency with the traveling speed of the coating process. Therefore, the length of the hot-air drying furnace is increased, and the time of passing through the hot-air drying furnace, which has been heated to a certain temperature, is increased so that the coil metal plate is heated to a predetermined temperature.

On the other hand, as a method of heating a metal plate without using a hot-air drying furnace, for example, Japanese Patent Application Laid-Open No. Sho 62-208591 discloses a high-frequency induction heating method. Since this high-frequency induction heating method is heating by an induction current flowing through a metal plate, it is direct heating, the heating time is short, and there is no need to enlarge the heating furnace. It is also an advantage that unnecessary peripheral environment is not heated.

By the way, as soon as the coating of one coil metal plate is completed, the coating of the next coil metal plate is started. Normally, immediately before the coating of one coil metal plate is completed, the transport driving device is temporarily stopped, and the rear end portion of the coil metal plate is joined to the front end portion of the next coil metal plate set on another uncoiler. Then, the transport driving device is operated again. Due to this resetting, the progress of the coil metal plate is stopped for about 1.5 minutes at present.

[0006]

SUMMARY OF THE INVENTION Heating furnace 1 (see FIG. 1)
In order to heat the coil metal plate 10 which proceeds continuously by
While detecting the temperature of the coil metal plate 10 with the temperature sensor 2 provided near the exit of the furnace 1, the temperature of the heat from the high-frequency induction heating devices 1a and 1b, which are heat sources, is controlled. Thus, the position measured by the temperature sensor 2 and the position heated by the heat source do not always match. When the coil metal plate 10 is traveling at a substantially constant speed, the actual temperature at the position heated by the heat source and the actual temperature at the position measured by the temperature sensor 2 change proportionally. Accurate control can be obtained by control. However, when the coil metal plate is stopped, the actual temperature at the position heated by the heat source rises, but the actual temperature at the position measured by the temperature sensor 2 does not rise, so that the temperature control is virtually not performed. Would. If heating is continued without such control, only the portion stopped in the furnace 1 will be over-burned.

In order to prevent such over-burning, the operation and stop of the transport driving device, that is, the advance of the coil metal plate,
It is conceivable to start and stop the high-frequency induction heating device according to the stop. However, since the coil metal plate has dropped to the room temperature or a temperature around it during the stop time, and has a heating time constant (time delay) as an object to be heated, the operation of the high-frequency induction heating device is restarted. However, even if the operation output is maximized by the temperature controller, the temperature does not reach the predetermined temperature immediately. Therefore, the portion of the coil metal plate stopped in the high-frequency induction heating furnace is insufficiently heated, that is, the baking and curing of the coating film or the like is insufficiently performed.

The present invention has been made in view of the above circumstances, and even if the transfer driving device is stopped due to replacement of the coil metal plate or for some reason, or even if the advance of the coil metal plate is stopped due to an accident, the coil is not affected. When baking paint and / or printing ink applied to metal plate,
An object of the present invention is to provide a baking apparatus that prevents excessive baking and does not cause insufficient bake hardening, and a bake hardening method using the baking apparatus.

[0009]

An apparatus for printing a coated or / and printed coil metal plate of the present invention, which has been made to achieve the above object, will be described with reference to FIG.

As shown in FIG. 1, the printing apparatus of the present invention comprises:
An apparatus for baking paint or (and / or) printing ink applied to a coil metal plate 10, which has a path 12 through which the coil metal plate 10 passes in a heating furnace 1. Apparatus 1a, 1b, coil metal plate 10
Speed measuring sensor 4 for measuring the traveling speed of the vehicle, high frequency induction
The heating devices 1a and 1b are converted into signals from the speed measurement sensor 4.
Controller 6 for controlling operation stop and path 1
Outlets 14a and 14 toward at least a part of
The constant-temperature hot-air blowing devices 13a and 13b where b is located are provided.

Further, a baking hardening method of the present invention, which has been made to achieve the above object, uses the above-described baking apparatus of the present invention, wherein a coil metal plate 10 coated with paint or / and printing ink is provided. Constant temperature hot air blowing device 13a / 1
3b and the high-frequency induction heating devices 1a and 1b to which the temperature control device 6 is added are introduced into the heating furnace 1 in operation and heated, and when the advance of the coil metal plate 10 is stopped, the operation of the high-frequency induction heating devices 1a and 1b Is stopped, and the coil metal plate 10 is heated by hot air from the constant temperature hot air blowing devices 13a and 13b.

The temperature of the constant-temperature hot air to be blown is preferably lower than or slightly higher than the lower limit of the crosslinking and curing temperature of the paint or printing ink applied to the coil metal plate 10.

[0013]

According to the baking hardening method of the present invention using the above-described baking device of the present invention, the high-frequency induction heating devices 1a and 1b and the hot-air blowing devices 13a and 13a.
13b are operating together. High frequency induction heating device 1
The induction current flows through the coil metal plate 10 and is directly heated by the hot air blowing devices 13a and 13b by the hot air blowing devices 13a and 13b.
This causes some indirect heating through the hot air.
Since the heating speed of the former is much faster than that of the latter, the coil metal plate 10 is heated mainly by high-frequency induction during the progress of the coil metal plate 10. When the heating temperature fluctuates due to some disturbance or the like, the operation of the temperature control device 6 controls the high-frequency induction heating devices 1a and 1b so that the temperature becomes constant. While the coil metal plate 10 is stopped, the operation of the high-frequency induction heating devices 1a and 1b is stopped, so that excessive burning does not occur. On the other hand, even during stoppage, the constant temperature hot air blowing device 13a
・ Coil metal plate 10 because hot air continues to be blown from 13b
Is heated to a constant temperature. Hot air heating takes a long time to heat, but since the coil metal plate 10 is stopped, the coil metal plate 10 is heated to a constant temperature for a sufficient time without difficulty.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic block diagram showing an embodiment of a printing and / or printing coil metal plate printing apparatus to which the present invention is applied.

In FIG. 1, reference numeral 10 denotes a painted coil metal plate, which advances at a predetermined speed in the direction of arrow X. Reference numeral 1 denotes a heating furnace, which has a path 12 through which the coil metal plate 10 passes in the center. 1a and 1b show a coil metal plate 1 in a heating furnace 1.
This is a high-frequency induction heating device including induction heating coils arranged in pairs with a path 12 of zero. 2 is heating furnace 1
A temperature sensor 3 composed of a radiation thermometer provided opposite to the coil metal plate 10 near the outlet of the sensor 3 is a converter for converting a signal from the temperature sensor 2. Reference numeral 4 denotes a speed measurement sensor for measuring the traveling speed of the coil metal plate 10, and reference numeral 5 denotes a converter for converting a signal from the speed measurement sensor 4. 6 receives the signals from the signal converters 3 and 5 and
This is a temperature controller that performs linear velocity control by control (proportional control / integral control / differential control). An analog-digital converter 7 converts an analog signal into a digital signal and vice versa. Reference numeral 8 denotes a control circuit that receives a digital signal from the analog-digital converter 7 and processes the digital signal based on a set program. Reference numeral 9 denotes a high-frequency oscillator that operates under the linear velocity control from the controller 6 that receives the processing signal output from the control circuit 8 and converted into an analog signal by the analog-digital converter 7, and outputs the processed signal to the high-frequency induction heating devices 1a and 1b. is there. 13a and 13
b is a hot-air blowing device disposed in the heating furnace 1, and blows out toward the path 12 of the coil metal plate 10.
14b is located.

The baking-hardening method using the apparatus of the above embodiment is carried out as follows.

The coil metal plate 10 is moved by a driving means (not shown) at a predetermined speed from the painting process in the direction of arrow X at a predetermined speed.
To proceed continuously. Before starting the heating operation, the material of the coil metal plate 10, the traveling speed of the coil metal plate 10, the temperature of the coil metal plate 10 before heating, the plate thickness of the coil metal plate 10, and the paint used for painting and the like. The heating temperature suitable for the drying temperature is input to the control circuit 8. These data are converted by the control circuit 8 into parameters for temperature setting. This parameter is converted into an analog signal by the analog-digital converter 7 and input to the PID controller 6 as an initial temperature setting value. The PID controller 6 instructs the high-frequency oscillator 9 on an appropriate frequency and current based on the initial set value by linear velocity control. The high-frequency oscillator 9 supplies a current to the high-frequency induction heating devices 1a and 1b based on the instruction. An induction current flows through the coil metal plate 10, and after the rise time, the coil metal plate 10 is heated to the initially set temperature. If the temperature of the coil metal plate 10 detected by the temperature sensor 2 deviates from the set temperature due to some cause (for example, a temperature change of the coil metal plate before heating due to a temperature change of the outside air), the high frequency oscillator is controlled by the PID controller 6. The frequency and current corrected by 9 are passed through the high-frequency induction heating devices 1a and 1b. Then, the coil metal plate 10 is corrected to the set temperature.

On the other hand, from the hot air blowing devices 13a and 13b, hot air having a temperature slightly higher than the lower limit of the crosslinking curing temperature is blown out through the outlets 14a and 14b all the time. When the coil metal plate 10 is continuously moving, the temperature obtained by both the heating by the hot air and the heating by the high-frequency induction is detected by the temperature sensor 2 and the PID controller 6 performs the control operation. A constant temperature can be maintained, and the paint on the coil metal plate 10 is dried and baked and hardened.

When the drying and baking hardening of one coil metal plate is completed in this way, the transport driving device is temporarily stopped in order to join with the next one coil metal plate.
At this time, the operation of the high-frequency induction heating devices 1a and 1b is also stopped. On the other hand, since the hot air is continuously blown from the constant temperature hot air blowing devices 13a and 13b, the coil metal plate 10 is heated to the constant temperature. Hot air heating takes a long time to heat, but since the coil metal plate 10 is stopped, the coil metal plate 10 is heated to a constant temperature for a sufficient time without difficulty. After the next coil metal plate is reset, the operation of the transport driving device is restarted. At the same time, the operation of the high-frequency induction heating devices 1a and 1b is restarted. While the coil metal plate 10 is stopped, the part where the curing of the paint has not been completed by heating with hot air is further cured by heating the high-frequency induction heating devices 1a and 1b as the coil metal plate 10 resumes its progress. Complete the curing of all the paint that was
Proceed outside the furnace.

The following experiment was attempted in accordance with the above embodiment.

An epoxy paint of 60 mg / dm ^{2 was} applied to a coil aluminum plate having a thickness of 0.25 mm, and the paint was dried at a speed of 30 m / min in an induction heating furnace having a length of 0.4 m. Hot air at 140 ° C. was always blown from the hot air blowing paths 14a and 14b at a speed of about 2 m / sec.
The coiled aluminum plate moving in the heating furnace 2 at a speed of 30 m / min can set the curing temperature of the epoxy paint to 1
The coating is heated to a temperature slightly above 40 ° C., and while the paint is being cured, the curing of the paint is completed, the solvent is removed, and a predetermined dry state is obtained. Stop the advance of the coil aluminum plate for about 1.5 minutes before finishing the processing of the coil aluminum plate for one roll and setting the next coil aluminum plate, and in the meantime, operate the high-frequency induction heating devices 1a and 1b. Stop. However, the portion of the coil aluminum plate located inside the heating furnace 1 is continuously heated only by hot air having a temperature near the lower limit of the curing temperature of the paint, and the curing is completed. The cured state of the coating film was satisfactory and satisfactory, and good performance was obtained. Next, the set coil aluminum plate was treated by the same operation to obtain a coating film in a good cured state.

[0023]

As described in detail above, according to the printing apparatus of the present invention and the baking hardening method using the apparatus, even if the continuously moving coil metal plate is stopped, the coating is applied to the coil metal plate. It is possible to prevent the paint and / or the printing ink from being over-baked and, conversely, not to cause insufficient baking. An extremely good cured coating film can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of an apparatus for printing a coated or / and printed coil metal plate to which the present invention is applied.

[Explanation of symbols]

1 is a heating furnace, 1a and 1b are high-frequency induction heating devices, 2 is a temperature sensor, 3 is a converter, 4 is a speed measurement sensor, 5 is a converter, 6 is a temperature control device, 7 is an analog-digital converter, 8 Denotes a control circuit, 9 denotes a high-frequency oscillator, 10 denotes a coil metal plate, 12 denotes a coil metal plate passage, 13a and 13
b is a hot-air blowing device, and 14a and 14b are the outlets.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B05C 9 / 12,9 / 14 B05D 3/02 B05D 7/14

Claims (2)

(57) [Claims] A paint or / and / or a coating applied to a coil metal plate.
A high-frequency induction heating device having a path through which a coil metal plate passes in a heating furnace, and a temperature control device added to the path, and a coil metal.
A speed measuring sensor for measuring the traveling speed of the metal plate, the high frequency
The induction heating device is driven by a signal from the speed measurement sensor.
A coil metal plate printing apparatus , comprising: a controller for controlling operation stop; and a constant-temperature hot-air blowing device in which a blowing port is located toward at least a part of the path. 2. A coil metal plate coated with a paint and / or printing ink is introduced into a heating furnace in which a high-frequency induction heating device having a constant-temperature hot-air blowing device and a temperature control device is in operation, and is advanced to be heated. When the advance of the coil metal plate is stopped, the operation of the high-frequency induction heating device is stopped, and the coil metal plate is heated by hot air from a constant-temperature hot-air blowing device. Bake hardening method.