JP2000081328A - Measurement method for running sheet-shaped object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously measure a running sheet-shaped object without any interruption by setting a sensor configuration to two series, using one of them for measuring the sheet-shaped object and the other for moving the sheet-shaped object in a width wise direction to calibrate the sensitivity of the sensor. SOLUTION: X rays 7 being emitted from an X-ray tube 211 for calibration are transmitted through a sheet-shaped object 1 and are applied to an X-ray detector 212 for calibration, and the level of the amount of incident X rays is measured and is converted into the thickness of the sheet-shaped object. A group of the X-ray tube 211 for calibration and the X-ray detector 212 for calibration is used as a calibration sensor, while a group of an X-ray tube 221 for measurement and an X-ray detector 222 for measurement is used as a measurement sensor. The sensor for calibration is subjected to full-span calibration at a point A, is subjected to sensitivity calibration by a reference calibration object 4 with a thickness that becomes a reference at a point B, rushes into the section of the sheet-shaped object at a point C, and measures a thickness on the sheet at a point D. The sensor for measurement and the sensor for calibration measure the same point of the sheet-shaped object that runs in three directions marked by arrows, thus calibrating a measurement value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method for a traveling sheet-like material for measuring, for example, surface temperature, thickness, moisture content, ash content and the like of a sheet traveling at a high speed in a non-contact manner. .

[0002]

2. Description of the Related Art For example, a vinyl sheet or the like is obtained by extruding a molten molding resin material from a molding roll, and the extruded vinyl sheet is continuously run and wound up on the roll.

When measuring measurement elements such as temperature, gloss, reflectance, thickness, and transmittance of the sheet-like object in a non-contact manner as necessary during traveling, a temperature sensor, a gloss sensor, a reflectance A sensor, a thickness sensor, and a transmittance sensor are employed, and these sensors are reciprocated in the width direction of the sheet to obtain measurement data of the measurement element.

Calibration of sensors is essential for the following reasons. That is, the sensitivity of the sensor generally changes due to factors such as temporal fluctuation of the ambient temperature, temporal fluctuation of the ambient humidity, temporal fluctuation of the atmospheric pressure, contamination of the sensor due to the adhesion of dust, drift of the accompanying electronic circuit, and the like. It is known. In general, a traveling sheet-like material is often produced continuously for several tens of minutes to several hours in time, and the production amount is often several kilometers or more in length. Therefore, the sensitivity calibration of the sensor requires periodic sensitivity correction within a short time interval, preferably with zero sensitivity calibration time, in order to always minimize the measurement error.

In the prior art, the sensitivity of the sensor is calibrated by reciprocating the sensor 2 beyond the width of the sheet 1 as shown in FIG. The so-called sensitivity calibration of the sensor 2, such as the full span calibration of the sensor, the gain calibration by the reference calibration object 4, the zero point drift correction, etc. is performed in the B portion.

The reason why the sensitivity of the sensor is calibrated in a portion where the sheet-like object does not exist is that gain calibration and full span calibration can be performed because the reference calibration object 4 can be installed.

[Problems to be solved by the invention]

As described above, the sensor 2 is, for example, C shown in FIG.
After the measurement of the sheet in the section D or D, it is necessary to return to the portion where the sheet does not exist, and perform the sensitivity calibration periodically. Therefore, during that time, the measurement of the sheet-like material must be interrupted as shown in FIG. That is, in FIG. 4, there is no sensor trajectory 6 on the sheet-like object 1 traveling in the direction of the arrow 3 indicating the traveling direction of the sheet, and the section of the trajectory indicated by the broken line is the section where the measurement of the sheet-like object is interrupted. It is. An object of the present invention is to continuously measure a running sheet without interrupting the measurement.

[0008]

In order to solve this problem, the sensor configuration is divided into two lines, one line is used for measuring a sheet-like object, and the other line is used for sensitivity calibration of the sensor. The sensor for sensitivity calibration is movable in the width direction of the sheet-like object, that is, in the direction perpendicular to the running direction, and the movable area covers both the reference calibration object and the sheet-like object.

[0009]

The operation of a typical sensitivity calibration will be described with reference to FIG. The full span of the calibration sensor 21 is confirmed at the point A, and the sensitivity calibration by the reference calibration object 4 is performed at the point B. It rushes into the area of the sheet from point C and reaches point D. The corresponding measuring point of the sheet at that time is D1
It is a point. Since the sheet-like object travels in the direction of arrow 3 indicating the traveling direction, the measurement sensor 22
To the point D2 just below.

The measured value of the calibration sensor at the point D1 and the measured value of the measurement sensor at the point D2 after the predetermined short time have to be identical because the same point on the sheet-like material 1 is measured. is there. Therefore, the measurement sensor is calibrated by the calibration sensor calibrated with the reference calibration object.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. In this embodiment, a running sheet 1 such as a plastic sheet, a vinyl sheet, a paper sheet,
This is an example in which the thickness of a metal sheet or a nonwoven sheet is measured by an X-ray transmission method.

In FIG. 1, an X-ray 7 radiated from a calibration X-ray tube 211 passes through a sheet-like material (eg, a plastic sheet) 1 which is a material to be measured and passes through a calibration X-ray detector 21.
2 is incident. The magnitude of the incident X-ray is measured and converted to the thickness of the sheet. That is, when the sheet is thick, the amount of X-ray incidence is small because the absorption by the sheet is large, and when the sheet is thin, the absorption of the X-ray is large because the absorption of the sheet is small. The thickness of the sheet is measured using the transmission law.

In FIG. 1, a set of a calibration X-ray tube 211 and a calibration X-ray detector 212 is defined as a calibration sensor. A set of the measurement X-ray tube 221 and the measurement X-ray detector 222 is defined as a measurement sensor. The calibration sensor is full-span-calibrated at point A, sensitivity-calibrated with a reference calibration object 4 having a reference thickness at point B, enters the section of the sheet at point C, and at point D the thickness on the sheet. Measure the length. Since the sheet-like object is traveling in the direction of arrow 3 indicating the traveling direction, the measurement portion reaches immediately below the measurement sensor after a predetermined time. At this time, the measured value of the thickness by the measuring sensor and the measured value of the thickness by the calibration sensor should be the same because the same position of the sheet is measured. That is, the thickness measured by the measurement sensor is calibrated by the calibration sensor.

FIG. 1 shows an embodiment in which the sensor is an active sensor. Obviously, the present invention can be applied to both active and passive sensors. An example of a passive sensor is a temperature sensor. When the temperature of a sheet is measured in a non-contact manner, a light receiver such as a thermopile is used as a sensor. In this case, since the temperature of the sheet is measured by receiving the temperature radiation infrared rays from the sheet, an active light emitting tube corresponding to the X-ray tube in the above-described example of the thickness measurement is unnecessary.

Although the example of FIG. 1 illustrates the case of thickness measurement, other measurement elements, such as the thickness of the coating material on the sheet temperature sheet, the haze of the sheet, the roughness of the sheet, and the transmittance of the sheet It is clear that the present invention can be applied to various measurement elements for non-contact measurement such as sheet gloss, sheet weight per unit area, sheet color tone measurement, sheet water content, and sheet ash content.

In FIG. 1, it is also clear that the measurement sensor does not violate the gist of the present invention whether it is stationary or moving.

[0017]

As described above, in the measuring method for a traveling sheet-like object according to the present invention, it can be said that the measuring element of the sheet-like object can be continuously measured without interruption time for calibration of the sensor. effective.

It is also clear that if the reference calibration object is moved to the position 41 in FIG. 1, the role of the calibration sensor can be replaced by the measurement sensor, and conversely, the role of the measurement sensor can be replaced by the calibration sensor at any time. It is.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.

FIG. 2 shows a calibration procedure.

FIG. 3 is a schematic diagram showing a measurement in the related art.

FIG. 4 is a diagram showing a trajectory of a measurement point in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Running sheet-like object 2 ... Sensor 21 ... Calibration sensor 22 ... Measurement sensor 211 ... Calibration X-ray tube 212 ... Calibration X-ray detector 221 ... Measurement X-ray tube 222 ... Measurement X-ray detector 3 … Arrow indicating the running direction 4… reference calibration object 5… section without sheet

Claims (1)

[Claims] 1. A measuring sensor for measuring a measuring element of a traveling sheet-like object and a calibration sensor movable in a width direction of the traveling sheet-like object are provided. A sensitivity measuring method for a traveling sheet-like object, wherein the sensitivity of the sensor is calibrated by a calibration sensor.