JP2561951B2 - Mist detection method and device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal sheet, and particularly to pre-cage detection of a can material sheet having a high possibility of causing defective welding of a side seam portion of a metal can at the time of the first cutter. The present invention relates to a method and a device for releasing this out of the system.

Conventional technology Conventionally, defective welding of the side seam portion of a metal can was detected by the welding monitor of the side seam welder, an air tester method, and the welding current detection method shown in Japanese Patent Publication No. 60-56597. .

Problems to be Solved by the Invention In the conventional can manufacturing process, an insulator such as ink or paint, that is, a mist, which adheres to the surface of a metal material before can forming, especially near the side seam portion, is detected while in a sheet state. I didn't do any special work. This is because the improvement of printing technology and coating technology has reduced the adhesion of ink and paint to unused areas.

However, in reality, these mists cause welding defects due to increased contact resistance during the side seam welding work in a resistance welding machine, and the copper wire used during welding breaks, resulting in production efficiency There has been a drop in. In some cases, expensive welding rolls were damaged or had to be replaced.

Furthermore, since the conventional side seam welding defect detection method is detected at the same time as or after welding, it is difficult to determine that the detected defect is necessarily caused by mist, and therefore it is difficult to manage defective lots or target lots. Spent a lot of time processing.

 The present invention solves these problems.

Means for Solving the Problems In order to solve the above problems, the present invention particularly has a mist in a portion forming a side seam portion of a can body, and when the side seam portion is welded, a welding defect occurs in that portion. In view of this, a mist detection device consisting of a pair of upper and lower conductive check rolls is installed in front of the first cutter, and the mist such as paint adhering to the varnish-excluding part of the metal sheet is detected. It is released to the outside of the system.

By this, before the side seam welding operation, a defective sheet in which welding failure may occur is pre-excluded, thereby forming a defective can.

Action The present invention, a pair of conductive check rolls arranged on both sides of the non-painted portion for detecting the presence or absence of mist in the non-painted portion of the metal sheet on which printing coating or the like is performed, and a detected sheet between the rolls. It comprises a current sensing device that senses the current passed through it, and a control device that emits a predetermined signal in response to the interruption of the current when the current sensing device senses the interruption of the current.

The signal transmitted from this control device drives the sheet selection device and also interlocks with the ejection device to eject the sheet having mist out of the system.

EXAMPLE FIG. 1 is a side view of a part of a can-making sheet feeding device incorporating the present invention, and FIG. 2 is a schematic plan view thereof.
In these figures, reference numeral 10 is a printed large-sized metal sheet. Each of the sheets 10 is transferred to the upper and lower roll cutters 1 by a known first conveyor device (not shown).
The first cutter 16 composed of 2,14 is supplied. Metal sheet
After 10 is cut to a predetermined width by the first cutter 16, it is conveyed to the second cutter 20 by the second conveyor device 18 and cut to a predetermined length there, and then to a can body processing device (not shown). It is supplied with. The carrying, cutting, and processing steps are known.

The mist detection device 22 of the present invention is preferably the first cutter 16
It is provided just before. Here, the mist means a foreign substance such as an adhered substance of paint.

Each unit 24 of the mist detection device 22 composed of a plurality of units is arranged with a predetermined dimension width in the direction orthogonal to the first conveyor device and is arranged to face the surface of the metal sheet 10 conveyed on the conveyor device. There is.

Each of the units 24 (six in FIG. 2) of the mist detecting device of the present invention have the same structure, and only one of them will be described in detail below. Mist unit 24
As shown in FIG. 3, a conductive conduction upper roll 26 which is located on the upper surface of the sheet 10 and detects mist in a portion corresponding to the side seam portion of the upper surface and a lower surface of the sheet 10 are located. A conductive conduction lower roll 28 arranged to face the upper roll 26 for detecting mist in a portion corresponding to a side seam portion on the lower surface, and respective rolls.
Flexible upper conductors 30 and lower conductors 32 that electrically connect the surfaces of 26 and 28 to the central control unit, and the upper surface of the supplied metal sheet 10 that is slightly upstream of the upper roll 26 and are pressed and held. The pressing roll 34 and upper and lower frames 36, 38 elastically holding these rolls.

On the other hand, behind the first cutter 16, as shown in FIG. 1, there is provided a magnet conveyor 40 which magnetically holds the upper surface of the sheet cut by the cutter. Near the downstream end of the conveyor, the pull-out roller 42 is placed opposite to the lower surface of the conveyor 40.
Is provided. The roller 42 is rotated clockwise by a motor 44. Further, the magnet conveyor 40 is provided with a vertically movable sheet sorting device, that is, a stopper 46. When the stopper 46 moves upward, the sheet 10 that has entered the conveyor 40 is fed to the pull-out roll 42, but in the lower normal position, the metal sheet 10 piece fed by the conveyor 40 is placed under the conveyor 40. It has a function to stop and hold. The vertical movement of the stopper 46 is performed by a command from the control device.

In the present invention, the printed metal sheet 10 is fed from the left side to the right side in FIG. 1 on the first conveyor. If the sheet immediately before the first cutter 16 is reached, as shown in FIG.
The pre-gauge 48 and the gauge roll 50 supporting both sides of the sheet 10 adjust the posture of the sheet 10 on both sides of the sheet 10, and at the same time, the pressing roll 34 of each unit 24 presses the upper surface of the sheet 10 to fix the metal sheet 10. Holds in a stable position.

The upper and lower rolls 26 and 28 of each unit 24 are, as shown in FIG. 4, the upper and lower portions of the printed portion on both sides of the metal sheet 10, that is, the metal surface between the coating surfaces 52, which is the side seam portion when forming a can. The parts are arranged in contact with each other, and a predetermined current flows between them.

If the mist 56 is present on the surface of the metal surface 54,
As shown in FIG. 5, the roll contacting the surface of the sheet
26 is released from the metal surface 54, which interrupts the electric current between the two rolls, and detects the attachment of the mist 56 by sensing this by a predetermined method.

6 and 7 show an example of the mist detection circuit and the rejector operation circuit of the present invention, and their flowcharts.

As can be seen from these figures, when the mist is detected, a current is passed between the rolls 26 and 28 and the metal sheet 10. Fourth
As shown in the figure, in the normal case where there is no mist on the metal sheet 10, the current flows as specified and the photocoupler PC as the current sensing device is in the ON state. In this case, no defective signal is generated, the shift table of the internal CPU is held in the state of "0", and the stopper 46 hangs down to the roller lower surface of the conveyor 40 (see FIG. 1).

Therefore, when a normal sheet is supplied by the first conveyor, the sheet is cut into a predetermined width by the first cutter 16 after passing through the mist detecting device 22. The cut sheet piece is supported by the magnet conveyor 40, and is stopped and held at a position where the leading end of the sheet piece is in contact with the stopper 46.

Then, the magnet of the magnet conveyer 40 is turned off to drop the sheet piece onto the second conveyer 18, and the second conveyer 18 feeds the sheet piece to the second cutter 20 which is the next operating portion.

For example, as shown in FIG.
There is a roll 26 of a predetermined unit in the mist detection device 22.
Or, when 28 comes off the surface of the sheet 10, the photocoupler PC
The current flowing to the photocoupler does not flow and the photocoupler does not turn on, and a defective signal is generated. As a result, the shift table becomes in the state of "1", and in response thereto, the signal and the timing signal from the slitter main body are timed and the stopper 46 is lifted between the rollers of the conveyor 40. When the sheet 10 is cut by the first cutter 16 in this state, as shown in FIG.
However, since the corresponding stopper 46 of the unit that has detected the mist 56 is lifted in the roller at this time, the sheet is not stopped by the stopper,
It is sent to a reject tray 58 by a pull-out roller 42 as a discharging device driven by a motor 44, and is stacked there. However, the normal sheet in which the mist is not found is stopped and held below the magnet conveyor 40 by the stopper 46 as described above, and the defective sheet is fed onto the reject tray 58 and then dropped onto the second conveyor 18, It is fed in the direction indicated by arrow 60 (Fig. 8).

After a series of sorting operations are completed, the stopper 46 immediately returns to the normal position shown in FIG. 1 and stands by as a stopper for the next normal metal sheet.

When a defective signal is transmitted and the rejector is activated, an alarm such as light and sound can be generated at the same time to call the operator's attention (Fig. 7).

Although the present invention has specifically described only the sheet for metal cans,
It can also be widely used to find surface mist on other sheets.

Effects of the Invention According to the present invention, the following effects can be obtained.

(1) The frequency of defective welding is reduced.

(2) The production operation rate can be improved by reducing the number of breaks in the welding copper wire.

(3) Gauge defective products that occur in the printing and painting process can be detected early before welding the side seam parts and can be eliminated, and troubles such as damage or replacement of expensive welding rolls of the welding machine occur. lost.

(4) If a defective can product is found, it has been necessary to eliminate all metal sheet lots (about 30 to 50 cans per sheet) for lot processing. The use of the device makes such wasteful disposal unnecessary.

(5) The device of the present invention can be easily and inexpensively mounted by merely modifying the conventional slitter.

(6) The effect of equipping one of two lines producing the same can type with the device of the present invention is as follows, and it can be seen that the effectiveness of the device of the present invention is extremely remarkable.

(7) According to the device of the present invention, it is possible to determine the presence / absence of an ultra-thin film transparent coating, which is difficult to discriminate with an optical type (optical sensor / camera image processing, etc.) means.

[Brief description of drawings]

FIG. 1 is a schematic view of a slitter equipped with the mist detection device and a rejector of the present invention, FIG. 2 is a schematic plan view of FIG. 1 showing a flow of a defective metal sheet, and FIG. 3 is an elevation view of a mist detection device unit, FIGS. 4 and 5 show the relationship between the upper and lower rolls of the mist detection device and the metal sheet. FIG. 4 shows an example of a normal sheet, and FIG. 5 shows an example of a case where there is mist. FIG. 6 is a diagram showing an example of a control circuit for operating the present invention, FIG. 7 is a diagram showing an example of a flow chart for operating the present invention, and FIG. 8 is a diagram showing an operation example of the device of the present invention. Explanation of reference numerals 10: metal sheet, 16: first cutter 22: mist detector, 24: unit 26: upper roll, 28: lower roll 30: upper conductor, 32: lower conductor 34: press roll 40: magnet conveyor, 42 : Pull-out roller 46: Stopper, 52: Coating surface 54: Metal surface, 56: Mist 58: Reject tray

Claims (4)

(57) [Claims] 1. A mist detecting method for detecting the presence or absence of mist in a non-coated portion of a metal sheet coated by printing or the like, wherein a pair of upper and lower continuity check rolls are arranged in contact with both surfaces of the non-coated portion, A mist detecting method in which the presence or absence of mist is detected by energizing the sheet through the sheet to be detected and separating the roll by the mist on the sheet surface and disconnecting the current from the sheet surface. 2. A mist detecting device for detecting the presence or absence of mist in a non-coated portion of a metal sheet coated by printing or the like, comprising a pair of conductive check rolls arranged in contact with each other on both sides of the non-coated portion. A current sensing device that senses a current flowing between the rolls through the sheet to be detected; and a control device that, when the current sensing device senses a current interruption, sends a predetermined signal in response to the interruption. A mist detection device comprising: 3. The mist detecting device according to claim 2, wherein the metal sheet is a large-sized metal sheet for molding a metal can, and the mist detecting device is arranged in front of the first cutter. 4. The mist detection device according to claim 2, a sheet sorting device that selectively operates according to a signal from a control device of the mist detection device, and a sheet sorted by the sheet sorting device to the outside of the system. And a discharging device for discharging the defective sheet.