JPS61114953A - Displacement detecting method of web side edge and device - Google Patents

Abstract

PURPOSE:To analogically detect the web side edge position under no contact at high precision by providing a pair of detectors having gas outlet pipes and gas inlet pipes at positions where both side edges of a traveling web pass during the conveyance of a film or the like. CONSTITUTION:A pair of detectors made with gas outlet pipes 1L, 1R and gas inlet pipes 3L, 3R having a slit-like opening respectively are arranged at positions where both side edges of traveling web pass via conveyor rollers R1, R2. The constant-pressure air from the same pressurized gas source is invariably fed to both gas outlet pipes 1L, 1R via pipes 6L, 6R, the blowout air stream partially cut off by the web W is received by the gas inlet pipes 3L, 3R, the pressure is guided to a differential pressure gauge 11 via conduits 7L, 7R, and the displacement quantity of the web W is detected via the differential pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting displacement of a side edge of a running web such as film or paper.

[Prior art]

Long webs such as films and paper are often fed out at high speeds, conveyed, and wound up at high speeds when printing, coating, or other processing is performed on their surfaces. Lateral displacement, which is the phenomenon of so-called meandering, is likely to occur in the axle, in which it is displaced from a predetermined conveyance path. If this lateral displacement occurs, the web may come into contact with a conveyance guide or the like and be damaged, or problems such as printing displacement, cutting errors, or uneven winding may occur in subsequent web processing steps due to the lateral displacement. In order to prevent such accidents, it is necessary to immediately detect lateral displacement of the web when it occurs, and take appropriate measures to deal with the lateral displacement. Naturally, in order to detect the lateral displacement of the web, it is sufficient to detect the displacement of the side edge position of the web.

Conventional methods for detecting side edge displacement of a web include bringing the sensing part of a sensor into contact with the side edge of a running web;
For example, a method is widely used in which a detection rod is brought into contact with the side edge of the web, and the amount of movement of the side edge of the web is captured as a change in the angle of the detection rod to measure the displacement. In addition, as a non-contact method of detecting the side edge position of the web, a sensor consisting of a transmitter and a receiver using light, ultrasonic waves, etc. is installed, and the sensor detects whether light, ultrasonic waves, or air currents are blocked by the web. A method of detecting the position of the side edge of the web from an image taken by a camera is known.

However, in the method of bringing the sensing part of the senna into contact with the side edge of the web, the contact of the sensing part may cause scratches on the side edge of the web and destroy the tension parameter of the web. Moderate problems arise in use.

Therefore, it is desirable to detect the position of the side edge of the web in a non-contact manner, but in methods using light, ultrasonic waves, airflow, etc., the information obtained from a single sensor is simply the position of the web at the sensor installation position. It is a so-called digital device that only detects the presence or absence of the web. Therefore, in order to detect the position of the side edge of the web or the amount of displacement, it is necessary to install a large number of sensors in horizontal rows across the detection range. It is necessary to do this, and its sensitivity and accuracy cannot be said to be sufficient. Furthermore, when the web is photosensitive such as photographic film or transparent, a general photosensor cannot be used as the sensor.

On the other hand, in the camera-based method, the position of the side edge of the web is only displayed on the screen, and in order to obtain a signal representing the position of the side edge of the web, more expensive processing equipment is required. There are drawbacks.

The present invention has been made based on the above circumstances, and it is possible to directly obtain an analog signal representing the position of the side edge of a web with sufficient accuracy without contact, and to apply the same to a photosensitive web. It is an object of the present invention to provide a method for detecting displacement of a side edge of a web, which can be suitably applied, and a device used therefor.

Means for Solving Problem C] The above object is to provide gas blow-off pipes that are placed opposite to each other across the side edges of the running web at positions where the web passes through both sides, and to blow out the gas from the gas blow-off pipes. A method for detecting a displacement of a side edge position of a web by providing a pair of detectors each having a gas receiving tube and measuring a difference in gas pressure generated in the two gas receiving tubes; It includes 2
This was achieved by a web side edge displacement sensing device with measuring means for measuring the difference in gas pressure in the individual gas receiving tubes.

[For production]

The gas blown out from the gas blowout tube flows toward the opposed gas receiving tube, but the airflow flowing inside the side edge of the web hits the web running between the gas blowing tube and the gas receiving tube. The gas that is blocked and flows outside the side edges of the web continues as it is and enters the gas receiving tube, generating a pressure corresponding to the amount of gas flowing into the tube.

When the web shifts laterally, the amount of gas blocked by the web changes and the air pressure inside the gas receiving tube changes. That is, if the side edges of the web move outward from the center of the web, the amount of gas flowing into the gas receiving tube decreases and the pressure decreases, and if the side edges of the web move inward, the pressure within the gas receiving tube increases.

Therefore, in principle, it is possible to detect the displacement of the side edge position of the web by providing one such detector, but in the case of one detector, the displacement of the side edge position of the web is large and the gas reception is difficult. If the gas pressure supplied to the trachea of the tube fluctuates for some reason, it will be directly detected as a displacement of the web, making it impossible to obtain sufficient detection accuracy.

In the method of the present invention, which is characterized in that the above-mentioned detectors are provided on both sides of the web and detect the pressure difference therebetween, when the web is displaced, a pressure drop occurs in one detector, and at the same time, a decrease in pressure occurs in the other detector. Since a corresponding increase in pressure always appears on the detector, the detection sensitivity is doubled and the linearity of the detected value is greatly improved. Furthermore, since the pressure difference is measured, even if there is a slight variation in the gas supply pressure, it is canceled out and no errors occur, making it possible to detect web displacement with extremely high sensitivity and accuracy.

〔Example〕

Preferred embodiments of the present invention will be described below using examples.

FIG. 3 is a schematic diagram showing an example of a detector used in the present invention.

In the figure, 1 is a closed gas blowing tube having a narrow opening 2 for gas blowing on the lower surface, and 3 is a closed gas receiving tube having a slit-like gas receiving port 4 on the upper surface. 5 indicates a predetermined position of the web. In the figure, A and B are views of the gas blowing pipe 1 and the gas receiving pipe 3 as viewed from the web 5 side, respectively.

In this example, the gas outlet is a pore, but its shape is not limited to a pore, but can also be, for example, a slit-shaped portion of an appropriate shape, similar to the receiving side.

The length of the gas receiving port, R, is preferably longer than the expected maximum displacement of the web, for example, 1.5 times the slenderness, and in the case of a long gas outlet and pores, the array length)
It is desirable that La be longer than LR.

There is no particular restriction on the width of the outlet, but it is preferable that the flow be blown out from all parts at an even velocity, and for this reason, it is desirable that the opening area of the outlet is less than h of the cross-sectional area of the outlet pipe.

The width of the gas receiving port 40 is not particularly limited and may be appropriately determined depending on the shape of the gas outlet 2, the distance between the blowing port 2 and the receiving port 4, etc., but it is usually preferably in the range of 0.2 to 5 mm. .

The distance between the gas outlet 2 and the gas receiving port 4 is preferably narrow from the point of view of detection sensitivity, but considering the thickness of the wedge, vibrations caused by running, etc., the distance between the gas outlet 2 and the gas receiving port 4 is between 1 and 50 mm to avoid direct contact with the web.
It is desirable that it be within the range of my friend.
) The gas used for detection is not particularly limited and can be freely selected depending on the atmosphere in which the device is used, the properties of the target web, etc., but when used in the atmosphere, air is usually used. good.

Air produced by a conguntusa or the like not shown in the figure and adjusted to an appropriate pressure by a pressure reducing valve or the like passes through a vibro, is supplied to a gas blowing pipe, and is blown out from a gas blowing port 2. As shown by the arrow in the figure, part of the blown gas is blocked by the web 5, and the remaining part goes straight and reaches the gas receiving port 4, generating pressure inside the gas receiving tube 3. If the side edge of the web moves to the left in the figure, the pressure decreases, and if it moves to the right, the pressure increases. The pressure generated in the gas receiving tube 3 is guided through a pipe 7 to pressure measuring means (not shown).

The pressure of the gas supplied to the gas blowing pipe varies depending on the shape and dimensions of the detector, the pressure of the device atmosphere, etc., and is not particularly limited, but it is usually 0.1 when used under atmospheric pressure.
It is preferable to maintain a constant pressure within the range of 5 kg/i to 5 kg/i.

As the differential pressure measuring means, it is preferable to use various known differential pressure gauges that are normally used to measure gas differential pressures and can measure minute differential pressures of several millimeters of water column to several lθ millimeters.In particular, the measured value can be used as an electrical output in the end. Particularly preferred are those that can be extracted as

The results of differential pressure measurement are of course used for monitoring on a meter, but they can also be extracted as electrical signals and automatically recorded, or connected to an alarm device, web conveyance device, etc. through a microprocessor, etc. to measure the differential pressure, that is, the pressure of the web. It may be configured to issue an alarm when a certain amount of displacement occurs, automatically emergency stop the conveyance of the web, or automatically correct the displacement of the web by operating the conveyance rollers. .

When installing the detector, it is preferable to install the detector so that a predetermined position on the side edge of the web is located at the center of the gas receiving daylength LR. It is preferable to be able to adjust it depending on the width.

In FIG. 3, reference numeral 8 denotes a holder for the gas blow-off tube 1 and the gas reception tube 3, and the positions of the gas blow-off tube 1 and the gas reception tube 3 can be adjusted by loosening screws 9 and 10.

FIG. 1 is a schematic diagram of the apparatus of the present invention.

Components in the figure that have the same functions as those in FIG. 3 are numbered the same (however, the detector on the right is labeled R1, and the detector on the left is labeled L).

W is the web R, , R, is a conveying roller and the web W is 1
Drive in the direction of the white arrow. The same pressurized gas source (not shown) is connected to the vibros L and 6R, and air at a constant pressure is always supplied.

11 is a differential pressure gauge whose output is connected to an automatic recording device, an automatic control device, etc.

FIG. 2 shows a relationship curve between the detected differential pressure and the amount of web displacement actually measured by the device shown in this figure, which showed extremely good linearity, had sufficient sensitivity and accuracy for practical use, and had excellent repeatability. In the graph, the web displacement amount is shown as + on the left side, and the differential pressure is shown as the difference between the left side and the right side. The parameters of the detector used for this measurement were as follows.

Gas used: Air Gas supply pressure = 1 Yu/d Gas blowout pipe diameter: 25 mm Gas outlet: 2N1 gastric pores, 34 pieces LB m 1001
111 Gas receiving pipe diameter: 1811 Gas receiving ports 21 mt This makes it possible to detect the displacement of the transported web with high sensitivity and accuracy without directly touching the web. It has the advantage that it can be applied without any problems to webs that are difficult to measure in the past, such as transparent or photosensitive webs, and it is extremely easy to maintain and manage as it does not include any moving parts.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the web side edge displacement detection device according to the present invention, Fig. 2 is a graph showing the relationship between the amount of web displacement obtained by the device and the detected differential pressure, and Fig. 3 is the detection used in the same device. It is a side view of a container. 1... Gas outlet pipe 2... Gas outlet 3... Gas receiving tube 4... Gas receiving port 11... Differential pressure gauge W... Web

Claims (2)

[Claims] (1) A gas blowing pipe and a gas receiving pipe for receiving the gas blown from the gas blowing pipe are provided at passing positions on both side edges of the running web, and are placed opposite to each other with the side edges of the web interposed therebetween. . A method for detecting displacement of a side edge of a web, wherein a pair of detectors are provided, and displacement of the position of the side edge of the web is detected by measuring the difference in gas pressure generated within the two gas receiving tubes. (2) Gas blow-off pipes that are provided at passing positions on both side edges of the running web and are placed opposite to each other across the side edges of the web, and gas receiving pipes that receive the gas blown out from the gas blow-off pipes. A web side edge displacement sensing device comprising: a pair of detectors; and a measuring means for measuring a difference in gas pressure generated within the two gas receiving tubes.