JPH06312153A - Baking equipment for coated and/or printed metal sheet - Google Patents

Abstract

PURPOSE:To bake stably and accurately a coated or printed metal sheet in a heating oven regardless of the temperature variation generated when the metal sheet enters the heating oven or stops in the heating oven. CONSTITUTION:A heating mechanism including high frequency induction heating devices 16a and 16b for heating a coil metal sheet 10 during the time when the coil metal sheet 10 is passed through a coil metal sheet passage 14 in a heating oven 12, and a control circuit 36 for controlling the heating operation by high frequency induction heating devices 16a and 16b and a temperature sensor 22 for sensing the prior temperature just before entering the coil metal sheet passage 14 are equipped. The heat control for the heating mechanism and the proper changeover of the high frequency induction heating devices 16a and 16b to hot air blowing devices 18a and 18b are carried out by the control circuit 36 by means of sensing signals of the prior temperature sensor 22. The temperature of hot air from air plenums 20a and 20b of the hot air blowing devices 18a and 18b is sensed by a hot air sensor 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating and / or printing metal plate baking apparatus, in particular, a metal plate used as a material for can manufacturing, after coating and / or printing, it is continuously dried and baked. The present invention relates to a printing apparatus for.

[0002]

2. Description of the Related Art As a metal plate for painting or printing, a coil metal plate formed by winding a long thin metal such as iron or aluminum into a coil is known. Widely used as a material. The coil metal plate is conveyed while being unraveled by the conveyance drive device, and its surface is continuously coated or printed with patterns, letters, etc., and further clear coated, and then dried and baked and cured. Then, this is cut into a predetermined size.

Conventionally, in the above drying and baking, a hot air drying oven has been used to continuously heat the coil metal plate. In this, the coil metal plate after painting or printing is heated by passing through a tunnel-type hot-air drying furnace whose temperature is set within a predetermined temperature range, and drying and bake-curing are completed. In the case of heating using such hot air, since the temperature inside the drying furnace is raised and heating is performed by the atmosphere, it takes some time until the coil metal plate rises to an appropriate temperature.

In contrast to this method, JP-A-62-20859
No. 1 discloses a high-frequency induction heating method that does not use a hot-air drying furnace, and Japanese Patent Laid-Open No. 5-266 discloses heating a metal plate using a hot-air heating method using a hot-air blowing device and a high-frequency induction heating method. The method is described. The high-frequency induction heating method is to make an induction current flow through the metal plate to be heated to heat the metal plate itself.This shortens the heating time, downsizes the heating furnace, and raises the temperature of the surrounding environment of the metal plate. There is an advantage that it can be prevented.

In the above-mentioned printing apparatus, it is necessary to set the heating temperature to a temperature condition within a narrow range to perform heating in order to obtain a good finished state. The control of the heating operation of the metal plate is performed based on the temperature change of the metal plate, and conventionally, this control detects the temperature of the metal plate after passing through the heating furnace, and based on the detection signal of the heating mechanism, The form of feedback control was used to control the operation.

[0006]

However, in the conventional continuous printing apparatus for coil metal plates, the temperature is adjusted by the feedback control,
There was a problem of causing a poor printing. Immediately before the coating of one coil metal plate is finished, the transport driving device is temporarily stopped, the next coil metal plate is reset, and then the transport driving device is operated again. The stop time is about 1.5 minutes, but if heating is continued during that time, excessive baking due to excessive heating may occur. on the other hand,
If the heating operation is stopped while the transfer drive device is stopped, when restarting operation, some of the metal plates remaining in the heating furnace and the metal plate immediately before the restarting furnace at the start of restarting will have the same temperature inside the heating furnace. Does not rise sufficiently, which may result in insufficient baking.

The cause of defective printing depends not only on the heating state of the printing apparatus itself, but also on the temperature of the metal plate entering the heating apparatus. Usually, the temperature of the metal plate when entering the heating furnace may change due to changes in the type of coating or printing, or for some other reason. In the hot air drying oven,
When the temperature of the metal plate reaches the ambient temperature, the temperature does not rise any further. However, in the high-frequency induction heating method, the temperature of the metal plate rises with the passage of time, so the temperature of the metal plate when entering the heating furnace directly affects the temperature of the metal plate after heating is completed. Corresponding to this, it is necessary to adjust the heating temperature in the heating furnace. When entering at a low temperature, it is necessary to raise to an appropriate temperature with more heating energy than when entering at a high temperature,
Appropriate heating operation control is always required in response to changes in the pre-heating temperature of the metal plate.

The conventional feedback control based on the temperature of the metal plate is performed by detecting the temperature after passing through the heating furnace. Therefore, when the temperature of the metal plate before entering has changed by a predetermined value or more, it cannot be detected until the metal plate comes out of the heating furnace, so that appropriate heating operation control also becomes difficult. In the procedure of detecting an abnormality after passing through the heating furnace and starting the control of the heating device at that time, due to the time lag of the response in the temperature sensor and the time lag until the control start in the control circuit based on the signal from the sensor,
It is impossible to avoid defective baking within a certain range from the first occurrence of defective baking, and it is naturally difficult to avoid defective baking in advance.

The present invention has been made in view of the above problems, and an object thereof is to control a heating device in a quick response to a temperature change when a metal plate enters a heating furnace and to perform excessive baking. (EN) Provided is a printing and / or printing metal plate printing apparatus capable of preventing the occurrence of insufficient printing and printing in advance.

[0010]

A baking apparatus for painting or / and printing coil metal plate of the present invention, which has been made to achieve the above object, will be described with reference to FIG. 1 corresponding to an embodiment.

As shown in FIG. 1, the printing apparatus of the present invention comprises:
Heating furnace 12 equipped with high-frequency induction heating devices 16a and 16b
A device for baking paint or / and printing ink applied to the coil metal plate 10 that continuously passes through the coil, and is provided immediately before the opening where the coil metal plate 10 enters the heating furnace 12. , Control units 32, 34, 36 for outputting the temperature signal detected by the previous temperature detecting means 22 as a feedforward control signal, and a high-frequency oscillator 38 whose heating output is controlled by the feedforward control signal.
And high-frequency induction heating devices 16a and 16b arranged in the heating furnace 12 and controlled in heating temperature.

A baking apparatus according to another aspect of the present invention is a coating material applied to a coil metal plate 10 passing through a heating furnace 12 equipped with high frequency induction heating devices 16a and 16b, or
And a device for baking printing ink, which includes a pre-temperature detecting unit 22 provided immediately before an opening through which the coil metal plate 10 enters the heating furnace 12, and an opening through which the coil metal plate 10 discharges from the heating furnace 12. Post-temperature detection means 2 provided immediately after
4, and a control unit 26, 32, 34.3 which calculates and outputs an optimum heating control signal from the temperature signal detected by the front temperature detection means 22 and the temperature signal detected by the rear temperature detection means 24.
6, a high-frequency oscillator 38 whose heating output is controlled by the heating control signal thereof, and high-frequency induction heating devices 16a and 16b arranged in the heating furnace 12.

The specific structure of the heating mechanism in the coil metal plate baking apparatus of the present invention is as follows: the high frequency induction heating devices 16a and 16b having an induction magnetic field for the coil metal plate 10 and the coil metal plate passing through the heating furnace 12. 10 is a hot air blowing device 18a, 18b having air outlets 20a, 20b directed to at least a part of 10.

Air outlets 20 of the hot air blowing devices 18a and 18b
In the vicinity of a.20b, the temperature sensor 40 and the hot air blowing device 18 by the hot air temperature detected by the temperature sensor 40
It is preferable that a control unit 42 for feedback controlling the heating temperature of a · 18b is added.

[0015]

According to the coating and / or printing metal plate baking apparatus of the present invention, the temperature signal detected by the pre-temperature detecting means 22 provided immediately before the entrance of the coil metal plate 10 into the heating furnace 12 is used. Feed-forward control is performed by the control units 32, 34 and 36, and the high frequency induction heating device 16a.
Control heating of 6b. Therefore, if there is a temperature difference in the coil metal plate 10 before entering the heating furnace 12 due to various causes, this can be detected before starting the heating operation,
It is possible to control to heat at an appropriate temperature before occurrence of over-baking or under-baking.

According to another embodiment of the baking apparatus of the present invention, the coil metal plate 10 is discharged from the heating furnace 12 and the pre-temperature detecting means 22 provided immediately before the entrance of the coil metal plate 10 into the heating furnace 12. The heating of the high-frequency induction heating devices 16a, 16b is controlled by the control units 26, 32, 34, 36 by the temperature signal detected by the post-temperature detection means 24 provided immediately after the mouth. By detecting the temperature by both the front temperature detecting means 22 and the rear temperature detecting means 24, not only when there is a temperature difference in the coil metal plate 10 before entering the heating furnace 12, but also in the high frequency induction heating devices 16a and 16b. Even when it is detected afterwards due to the change in the heating state of No. 1, both are taken into consideration and more optimal heating control is performed. Therefore, it is possible to prevent excessive seizure and insufficient seizure.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing an embodiment of a printing or / and printed metal plate printing apparatus to which the present invention is applied.

Reference numeral 10 in FIG. 1 denotes a coil metal plate, which advances in the direction of arrow X at a predetermined speed. A heating furnace 12 has a coil metal plate passage 14 through which the coil metal plate 10 passes at the center. Reference numerals 16a and 16b denote high-frequency induction heating devices which are induction heating coils arranged in pairs in the heating furnace 12 with the coil metal plate passage 14 interposed therebetween. 1
Reference numerals 8a and 18b denote hot air blowing devices arranged in the heating furnace 12, and the hot air blowing device 2 faces the coil metal plate path 14.
0a and 20b are located. 22 is a coil metal plate 10
Is a front temperature detection sensor that is a radiation thermometer that detects the temperature immediately before entering the coil metal plate passage 14, and 24 is a radiation thermometer that is provided near the outlet of the heating furnace 12 so as to face the coil metal plate 10. The rear temperature detecting sensor 26 is a converter for converting the signals from the front temperature detecting sensor and the rear temperature detecting sensor 24. 28 is a speed detection sensor for measuring the traveling speed of the coil metal plate 10, and 30 is a speed detection sensor 2.
8 is a converter for converting the signal from 8. A controller 32 receives signals from the signal converters 26 and 30 and performs linear velocity control by PID control (proportional control, integral control, differential control). An analog-digital converter 34 converts an analog signal into a digital signal and vice versa. A control circuit 36 receives a digital signal from the analog-digital converter 34 and processes it based on a set program. Reference numeral 38 is a high-frequency oscillator that operates by the linear velocity control from the controller 32 that receives the processing signal that is output from the control circuit 36 and that is analog-converted by the analog-digital converter 34, and that outputs it to the high-frequency induction heating devices 16a and 16b. . 40 is a hot air blowing device 18a, 1
8b is a hot air temperature detection sensor for detecting the hot air temperature blown out by 8b. A controller 42 receives a signal from the hot air temperature detection sensor 40 and controls the generation of hot air. 44
Is a hot air generator that operates under the control of the controller 42 and generates hot air.

The operation of the embodiment having the above configuration will be described below. As a basic operation, first, the material of the coil metal plate 10, the traveling speed, the plate thickness, the appropriate drying temperature of the paint used for coating, etc. are input to the control circuit 36 in advance before the heating work is started. . These data are parameter-converted by the control circuit 36 for proper temperature setting. This parameter is used by the analog-to-digital converter 34.
Is converted into analog and is input to the controller 32 as an initial setting value of temperature. Based on the initial set value, the controller 32 gives an instruction signal to the high frequency oscillator 38 by linear velocity control so as to output an appropriate frequency and current. The high frequency oscillator 38 supplies a current to the high frequency induction heating devices 16a and 16b based on the instruction signal. As a result, an induced current flows through the coil metal plate 10, and after the rising time, the coil metal plate 10 is heated to the initial set temperature.

Next, the control based on the temperature of the coil metal plate 10 will be described. The coil metal plate 10 is moved at a predetermined speed by an arrow X at a predetermined speed from the coating process by a transport drive mechanism (not shown).
And is continuously transferred in the coil metal plate passage 14 in that direction. At this point, the temperature of the coil metal plate 10 immediately before entering the coil metal plate passage 14 is detected by the front temperature detection sensor 22 and is sent to the controller 32 via the converter 26. And the controller 3
2. The functions of the analog-digital converter 34 and the control circuit 36 control the high-frequency oscillator 38 based on the detection result of the pre-temperature detection sensor 22, and control the heating operation of the high-frequency induction heating devices 16a and 16b. That is, if the temperature of the coil metal plate 10 at the time of entry is within a predetermined range, the high-frequency oscillator 38 outputs a predetermined output. When the temperature is lower than the predetermined temperature, a higher output is output, and when the temperature is higher than the predetermined temperature, a lower output is output.

As a result, it becomes possible to significantly suppress the uneven printing that occurs in the conventional apparatus, especially when the conveyance of the coil metal plate is stopped or the printing failure immediately after the metal plate or the coating is changed.

On the other hand, even if it is determined by the temperature detection by the post-temperature detection sensor 24 that the temperature range deviates from the preset temperature range after the end of heating, the controller 32 instructs the controller 32 to correct the frequency and the current. Are supplied to the high frequency oscillator 38. Thereby, the high frequency induction heating device 1
The heating operation by 6a and 16b is corrected and the heating is properly performed. That is, the post-temperature detection sensor 24 and its control unit act as a backup.

From the hot air heating devices 18a and 18b,
Hot air at a temperature slightly higher than the lower limit of the cross-linking curing temperature is blown out from the outlet 2
It always blows from 0a and 20b. The hot air temperature detection sensor 40 detects the hot air temperature blown out by the hot air blowing devices 18a and 18b, and the controller 42 sends an instruction signal for controlling the hot air generation output to the hot air generator 44 to maintain a constant temperature. While the coil metal plate 10 is continuously advancing, the heating by the hot air and the high frequency induction heating device 16
Both heating operations by a and 16b are performed.
Then, the controller 32 controls the operation based on the temperature detection by the front temperature detection sensor 22 and the rear temperature detection sensor 24, so that the appropriate drying and baking-hardening work is performed.

When the work of drying and baking one coil metal plate 10 is completed, the next one coil metal plate 10 is prepared, and during that time, the transport drive device not shown in FIG. 1 is temporarily stopped. It At this time, a signal indicating the stop is sent to the controller 32, and from the controller 32, a signal to stop the heating by the high frequency induction heating devices 16a and 16b is sent to the high frequency oscillator 38. However, only the hot air blowing devices 18a and 18b continue to operate. This is to prevent the temperature of the coil metal plate 10 from decreasing during the stop. Proper heating by only hot air heating takes time, but heating by the high frequency induction heating devices 16a, 16b while the coil metal plate 10 is stopped is too strong. Therefore, only the hot air blowing devices 18a, 18b heat the coil metal plate 10. Prevent the temperature drop.

When the next setting of the coil metal plate 10 is completed, the operation of the transfer driving device is restarted. at the same time,
An instruction signal is issued from the controller 32 to the high frequency oscillator 38, and a predetermined output is sent from the high frequency oscillator 38, so that the operations of the high frequency induction heating devices 16a and 16b are also restarted. At this time, the high-frequency induction heating devices 16a and 16b are used for the parts that have not been sufficiently cured by heating with hot air during the stop.
When the heating is restarted, the curing proceeds, and the curing of the paint in all the portions inside the heating furnace during the stop is completed, and the coating proceeds to the outside of the heating furnace 12. According to the above-described embodiment, appropriate heating operation control is performed in response to the temperature change of the coil metal plate 10 before entering the heating furnace 12, and the occurrence of a heating failure state is prevented in advance.

Even when the coil metal plate 10 stops in the coil metal plate path 14 in the heating furnace 12, the high frequency induction heating devices 16a and 16b and the hot air blowing devices 18a and 18b.
Good drying and bake-curing are performed by appropriate switching control of.

The hot air temperature detecting sensor 40 installed near the hot air outlets 20a, 20b of the hot air blowing devices 18a, 18b detects the hot air temperature of the hot air blowing devices 18a, 18b. The controller 42 controls the output of the hot air generator 44 according to the detection signal from the hot air temperature detection sensor 40,
Prevents excessive or insufficient seizure of coil metal plates.

The present invention is not limited to the configuration of each of the above embodiments, and various modifications can be made within the scope of the invention. For example, the hot air blowing devices 18a and 18b
The air outlets 20a and 20b of the above can be set not only to be blown out from one place in the substantially central portion as in the above-described embodiment, but also to be blown out from a plurality of places, and the number of high frequency induction heating devices 16a and 16b can be increased. Can also be changed.

[0029]

As described above in detail, according to the coating and / or printing metal plate baking apparatus of the present invention, the temperature change of the coil metal plate transferred into the heating furnace and the metal plate due to some circumstances may occur. Drying by stopping in the heating furnace,
It is possible to control the heating operation of the heating mechanism so that a defective printed state does not occur. As a result, it is possible to achieve homogenization and smoothing of the painting and printing operations on the metal plate.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an overall configuration of a printing and / or printing metal plate printing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10 is a coil metal plate, 12 is a heating furnace, 14 is a coil metal plate passage, 16a and 16b are high frequency induction heating devices, 1
8a and 18b are hot air blowing devices, 20a and 20b are outlets, 22 is a front temperature detection sensor, 24 is a rear temperature detection sensor, 26 is a converter, 28 is a speed detection sensor, 30 is a converter, 32 is a controller, 34 Is an analog-digital converter, 36 is a control circuit, 38 is a high frequency oscillator, 40 is a hot air temperature detection sensor, 42 is a controller, and 44 is a hot air generator.

Claims (4)

[Claims] 1. An apparatus for baking paint or / and printing ink applied to a coil metal plate that continuously passes through a heating furnace equipped with a high frequency induction heating device, wherein the metal plate is inside the heating furnace. Front temperature detecting means provided immediately before the entrance to the door, a control section for outputting a temperature signal detected by the front temperature detecting means as a feedforward control signal, and a heating output controlled by the feedforward control signal. And a high-frequency induction heating device provided in the heating furnace. 2. A coating material applied to a coil metal plate passing through a heating furnace equipped with a high frequency induction heating device or /
And a device for baking printing ink, the pre-temperature detecting means is provided immediately before the opening for the metal plate to enter the heating furnace, and the opening is provided immediately after the opening for discharging the metal plate from the heating furnace. A rear temperature detecting means, and a control section for calculating and outputting an optimum heating control signal from the detected temperature signal by the front temperature detecting means and the detected temperature signal by the rear temperature detecting means,
A coil metal plate baking apparatus, comprising: a high-frequency oscillator whose heating output is controlled by the heating control signal; and a high-frequency induction heating device provided in the heating furnace. 3. The coil metal plate baking according to claim 1, wherein the heating furnace is provided with a hot air blowing device having a blowout port toward at least a part of the coil metal plate passing therethrough. apparatus. 4. A temperature sensor is provided in the vicinity of the hot air outlet of the hot air blowing device, and a controller for feedback controlling the heating temperature of the hot air blowing device based on the hot air temperature detected by the temperature sensor is added. Claim 3 characterized by
The coil metal plate baking apparatus according to [4].