JPH02227649A - Method and device for mist detection - Google Patents

Abstract

PURPOSE:To detect whether mist is present or not by arranging a couple of conduction check rolls on both surfaces of a sheet to be detected in contact, feeding electricity between the rolls through the sheet, and cutting off the electricity when the sheet leaves a roll surface owing to the mist. CONSTITUTION:The device consists of a conductive roll 26 which is positioned on the top surface of the sheet 10 to be detected and detects mist at the side seam corresponding part of the surface, a conductive roll 28 which is positioned on the reverse surface and operates similarly, flexible conductors 30 and 32 which connect both the roll surfaces electrically to a controller, a pressure roll 34 for the sheet 10, and support frame bodies 36 and 38 for them. Then a current is made to flow through the rolls 26 and 28 and sheet 10 and when one surface of the sheet 10 leaves the roll 26 or 28 because of mist on the top or reverse surface of the sheet 10, the current does not flow any more and a current sensing device generates a specific signal. Consequently, the mist can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to metal sheets, and in particular detects in advance, at the time of the first cutter, can material sheets that are likely to cause welding defects at the side seams of metal cans. , relates to a method and apparatus for releasing this to the outside of the system.

Conventional technology In the past, defective welding at the side seam of metal cans was detected using a welding monitor of a side seam welding machine, an air tester, or the welding current detection method described in Japanese Patent Publication No. 80-513597. .

Problems to be Solved by the Invention In the conventional can manufacturing process, insulators such as ink and paint, that is, mist adhering to the surface of the metal material, especially near the side seam, before can formation, are detected while the can is in sheet form. No special work was done for this purpose. This is because improvements in printing and painting techniques have reduced the amount of ink and paint that sticks to unnecessary areas.

However, in reality, these mist causes welding defects due to increased contact resistance when welding side seams with a resistance welding machine, and breaks in the copper wire used during welding, resulting in reduced production efficiency due to repair work. There were cases where a decrease in

In some cases, accidents have also occurred in which expensive welding rolls have been damaged or had to be replaced.

Moreover, with conventional side seam welding defect detection methods, detection is performed at the same time as welding or after welding, so it is difficult to determine that the detected defect is necessarily caused by mist. I was spending a lot of time processing rods.

The present invention solves these problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides that, in particular, if there is mist in the part forming the side seam of the can body, welding defects will occur in that part when the side seam is welded. In consideration of this, a mist detection device is installed in front of the first cutter to detect the mist of paint, etc. attached to the varnish removal part of the metal sheet, and discharge the defective sheet out of the system after cutting with the first cutter. .

As a result, before welding the side seam, any defective sheets that may cause welding defects are pre-swaged and removed.
This prevents the formation of defective cans.

Function The present invention includes a pair of conductive check rolls placed on both sides of the non-coated area of a metal sheet that has been printed and coated, etc., and a sheet to be detected between the rolls. The control device includes a current sensing device that senses the current flowing through the current sensing device, and a control device that generates a predetermined signal in response to an interruption in the current when the current sensing device senses an interruption in the current.

A signal transmitted by this control device drives a sheet sorting device and works in conjunction with a discharge device to discharge sheets containing mist to the outside of the system.

Note that the check roll can be replaced by a non-contact type sensor.

Embodiment FIG. 1 is a side view of a part of a can manufacturing sheet feeding apparatus incorporating the present invention, and FIG. 2 is a schematic plan view thereof. In these figures, reference numeral 10 is a large printed metal sheet. This sheet lO is transferred one sheet at a time by a known first conveyor device (not shown) to an upper and lower roll cutter 1.
A first cutter 16 consisting of 2.14 pieces is supplied. After the metal sheet 10 is cut into a predetermined width by the first cutter 16, it is conveyed to the second cutter 20 by the second conveyor device 18, where it is cut into a predetermined length and then transferred to a can body processing device (not shown). ). This conveyance, cutting, and processing steps are well known.

The mist detection device 22 of the present invention preferably includes the first cutter 1
It is set just before 6. Here, mist means foreign matter such as paint deposits.

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

Since all of the units 24 (six units in FIG. 2) of the mist detection device of the present invention have the same configuration, only one of them will be described in detail below. Mist unit 24
As shown in FIG. 3, an electrically conductive upper roll 26 is located on the upper surface of the sheet 1O and detects mist in a portion of the upper surface corresponding to the side seam portion, and
a conductive lower roll 28 disposed opposite to the upper roll 2G, which detects mist in a portion of the lower surface corresponding to the side seam portion, and each roll 28. A flexible main conductor 30 and a lower body 32 electrically connect the surface of 28 to the central control unit, and a metal sheet l slightly upstream of the upper roll 26 and supplied with the metal sheet l.
It consists of a presser roll 34 that presses and holds the upper surface of O, and upper and lower frames 36 and 38 that elastically hold these rolls.

On the other hand, behind the first cutter 16, as shown in FIG. 1, a magnetic conveyor 40 is provided which magnetically holds the upper surface of the sheet cut by the cutter. Near the downstream end of the conveyor, a pull-out roller 42 is provided opposite to the lower surface of the conveyor 40. The roller 42 is rotated clockwise by a motor 44.

The magnetic conveyor 40 is also provided with a sheet sorting device or stopper 46 that is movable up and down. Stopper 4
6 feeds the sheet 10 that has entered the conveyor 40 to the pull-out roll 42 when it moves upward, but in its normal downward position, the 10 pieces of metal sheets fed by the conveyor 40 are transferred to the lower part of the conveyor 40. It has the effect of stopping and holding it. This vertical movement of the stopper 4B is performed by commands from the control device.

In the present invention, a printed metal sheet 10 is fed on a first conveyor from left to right in FIG. When the sheet IO reaches just before the first cutter 1B, the posture of the sheet IO is adjusted on both sides by the brake gauge 48 and the gauge roll 50, which support both sides of the sheet IO, as shown in FIG. 24 presser rolls 34 press the upper surface of the sheet 10 to stably hold the metal sheet 10 in a prescribed position.

As shown in FIG. 4, the upper and lower rolls 26 and 28 of each unit 24 are located above and below the printed portion on both sides of the metal sheet 10, that is, the metal surface between the coated film surfaces 52, and the portion 54 that becomes the side seam portion during can forming. The parts are placed in contact with each other, and a predetermined current flows between them.

If the mist 5B is present on the surface of the metal surface 54, as shown in FIG. is blocked, and by sensing this using a predetermined method, the adhesion of the mist 56 is detected.

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 detecting mist, a current is passed between both rolls 26, 28 and the metal sheet 10.

As shown in FIG. 4, when there is no mist on the metal sheet 10, the current flows as specified, and the photocoupler PC as a current sensing device is in an ON state. In this case, no fault signal is generated, the shift table of the internal CPU is held in the "0" state, and the stopper 46 hangs down to the lower surface of the roller of the conveyor 40 (see FIG. 1).

Therefore, when a normal sheet is supplied by the first conveyor, the sheet passes through the mist detection device 22 and is then cut into a predetermined width by the first cutter 16.

The cut sheet pieces are supported by a magnetic conveyor 40, and are stopped and held at a position where the feeding tip of the sheet pieces collides with a stopper 46.

Next, the magnet of the magnetic conveyor 40 is turned off and the sheet piece is dropped onto the second conveyor 18, and the second cutter 20, which is the next operating part, is moved by the second conveyor 18.
It will be sent to.

For example, if mist 5 is placed on the sheet 10 as shown in FIG.
6, and when the roll 26 or 28 of the predetermined unit in the mist detection bag B22 separates from the surface of the sheet 10, the current flowing to the photocoupler PC stops flowing, and the photocoupler does not turn on and a fault signal is generated. It happens.

Therefore, the shift table becomes "1", and in response to this, the signal and the timing signal from the slitter body are synchronized, and the stopper 46 is lifted between the rollers of the conveyor 40.

When the sheet lo is cut by the first cutter 16 in this state, the cut sheet is sent to the magnetic conveyor 40 side as shown in FIG.
Since the corresponding stopper 48 of the unit that detected 6 is lifted into the roller, the sheet is not stopped by the stopper but is sent to the reject tray 58 by the pull-out roller 42 as a discharge device driven by the motor 44. and piled up there. However, normal sheets on which no mist was found are stopped and held at the bottom of the magnetic conveyor 40 by the stopper 4B as described above, and after the defective sheets are fed onto the reject tray 58, they are dropped onto the second conveyor 18. Arrow 60 (
It is fed in the direction shown in Fig. 8).

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

Note that when a defective signal is transmitted and the rejector is activated, an alarm such as light or sound can be generated at the same time to draw the attention of the worker (FIG. 7).

In addition to the conductive roll type that contacts the sheet surface, the mist detection device can also use a non-contact type sensor 62 as illustrated in FIG. 9 in combination or independently. Sensors used include lasers or optical sensors.
By using these sensors, it is also possible to detect mist of ink or colored paint (excluding transparent clear paint, etc.) with a diameter of about 1 ms.

Although the present invention has been specifically described with respect to sheets for metal cans, it can also be widely used to detect surface mist on other sheets.

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

(1) The frequency of welding defects is reduced.

(2) Production operation rate can be improved by reducing the number of disconnections of copper wire for welding.

(3) It is now possible to detect and eliminate gage defects that occur during the printing and painting process at an early stage before welding the side seam, which prevents troubles such as damage to or replacement of expensive welding rolls in welding machines. lost.

(4) When a defective can product is discovered, it was previously necessary to remove all the metal sheet lofts (approximately 30 to 50 cans per sheet) for loft treatment. ,
If this device is used, such wasteful disposal becomes unnecessary.6 (5) The device of the present invention can be easily and inexpensively installed on a conventional slitter with only a few modifications.

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

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a slitter equipped with the present mist detection device and rejector, Fig. 2 is a schematic plan view of Fig. 1 showing the flow of defective metal sheets, and Fig. 3 is an elevational view of the mist detection device unit. Figures 4 and 5 show the relationship between the upper and lower rolls of the mist detection device and the metal sheet; Figure 4 shows an example of a normal sheet; Figure 5 shows an example of a case where there is mist; FIG. 6 is a diagram showing an example of a control circuit that operates the present invention, FIG. 7 is a diagram showing an example of a flowchart for operating the present invention, FIG. 8 is a diagram showing an example of the operation of the present invention device, and FIG. The figure is a diagram showing an example of a mist detection device showing another embodiment. Explanation of symbols 10: Metal sheet 22: Mist detection device 26 Upper roll 30: Upper conductor 34: Presser roll 40: Magnetic conveyor 42: Pull-out roller 46
: Stopper 52: Coating surface 54: Metal surface
56: Mist 58, reject tray 8
2: Sensor 16: First cutter 24: Unit 28: Lower roll 32: Lower conductor 8 concave tail 9 figure

Claims (1)

[Scope of Claims] 1. A mist detection method for detecting the presence or absence of mist in a non-coated area of a metal sheet that has been printed, coated, etc., which comprises placing a pair of upper and lower conductivity check rolls in contact with both sides of the non-coated area. A mist detection method in which the presence or absence of mist is detected by applying electricity between the rolls through the sheet to be detected, and when the rolls are separated from the sheet surface due to the mist on the sheet surface and the electricity supply is cut off. 2. The mist detection method according to claim 1, wherein non-contact type sensors are arranged on the upper and lower surfaces of the detection sheet in place of or in addition to the continuity check roll. 3. A mist detection device for detecting the presence or absence of mist in a non-coated area of a metal sheet that has been printed or coated, which includes a pair of conductive check rolls placed in contact with both sides of the non-coated area, and between the rolls. A mist comprising: a current sensing device that senses the current flowing through the detected sheet; and a control device that transmits a predetermined signal in response to the interruption when the current sensing device senses an interruption in the current. Detection device. 4. The mist detection device according to claim 3, further comprising a non-contact type sensor arranged on the upper and lower surfaces of the detection sheet instead of or in addition to the continuity check roll. 5. A defective sheet comprising a sheet sorting device that is selectively activated by a signal from the control device according to item 3 or 4 above, and a discharge device that discharges the sheets sorted by the sorting device to the outside of the system. Sorting device.