JPH0720251A - Sheet-like object characteristic measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a characteristic measuring device capable of stably detecting an end portion in the width direction of paper. [Structure] A sheet-like object that travels with a predetermined width,
A first head and a second head, which are arranged to face each other with a predetermined gap sandwiching the sheet-like object, and reciprocate simultaneously in the width direction of the sheet-like object, and the first and second heads are provided with predetermined values. Measuring means for irradiating the measuring light and the reference light having the wavelength of 5 to measure the characteristics of the sheet-like object from the attenuation of the light, and the measuring means are provided to face the first and second heads with the sheet-like object interposed therebetween. In a characteristic device for a sheet-like object equipped with edge detecting means for detecting an edge in the width direction of the sheet-like object by the light-emitting means and the light-receiving means, the sheet-like object facing the light-emitting element and the light-receiving element The presence of the sheet-like object is detected based on the intensity of light from the light-emitting element passing through the polarizer and the sheet-like object.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a characteristic measuring device for measuring the characteristic of a sheet-like substance (for example, the water content of paper) online, and more specifically, the edge portion of a highly transparent sheet-like object. The present invention relates to a measuring device with improved detection accuracy.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view showing a general structure of an apparatus for measuring the water content of a sheet of paper. In the figure, 1 is a paper that runs in a direction perpendicular to the paper surface of FIG. 2, and 2 and 3 are an upper head and a lower head that move left and right on the paper surface of FIG. 2 ′ and 3 ′ are positions of the upper head and the lower head showing a standby state such as when moisture is not measured, 4 is an upper beam supported so as to be held by the upper head 2, and 5 is set to be held by the lower head 3. Lower beam supported by.
6 and 7 are stands.

FIG. 4 is a diagram showing a general structure of a moisture measuring device incorporated in the upper head and the lower head. In the figure, reference numeral 2 is an upper head (light emitting portion), 3 is a lower head (light receiving portion), which are arranged to face each other with the paper 1 being the object to be measured interposed therebetween. In the light projecting unit 2, the light from the light source 16 is transmitted to the lens 1
The light is collimated by 7 and is converted into intermittent light by the chopper wheel 18, and then the paper 1 is irradiated through the irradiation window 19.
The chopper wheel 18 has a filter 20 that transmits light (M light) of 1.94 μm that is absorbed by moisture.
And 1.8 μm light (R light) that is not absorbed by water
Is provided with a filter 21 for transmitting the light, and the paper 1 is irradiated with M light and R light alternately in accordance with the rotation. In the light receiving section 3, the light transmitted through the paper 1 enters through the entrance window 22, is focused by the lens 23, and is condensed on the light receiving element 12. This and the light receiving element 12 and the M light R light chronologically detected outputs subjected to calculation of V _R / V _M applied to the arithmetic unit 13.

By the way, in such a measuring apparatus, a mechanism for detecting the edge of the paper although the upper head 2 and the lower head 3 move in the left-right direction on the paper surface 1 is provided. FIG. 5 is a plan view (a) and a side sectional view (b) showing a conventional paper edge detecting device. It should be noted that the same elements as those in FIG.

In the figure, 31 and 32 are irradiation windows 1 on a plane.
Projection windows 40 and 40a are provided with the projection window 9 sandwiched therebetween.
It is a light-emitting body (LED) that emits light via 1, 32. Reference numerals 31b and 32b denote light receiving elements that receive the light from the light emitters 40 and 40a through the light receiving windows 31a and 32a.
Reference numeral 30 is a shutter that blocks the light of the light source 16 in response to the detection of the paper edge.

The reason why the paper edge detection and the shutter mechanism are necessary in the above structure will be described. That is, the upper head 2 and the lower head 3 move above the upper beam and the lower beam over the paper width during measurement. In that case, when the shutter is not provided, the light from the light source 16 is directly received by the light receiving element 1 when the light is off the edge of the paper.
2 will be incident. As a result, the signal from the light receiving element 12 is saturated, the head is inverted, and the light receiving element 1
Even if 2 is cut off with paper, it will be impossible to measure for a while.

According to the above construction, for example, when the head moves in the direction of arrow B, the light receiving element 31b senses the light from the LED 40 at the moment when it leaves the paper edge. The shutter 30 receives the signal from the light receiving element 31b and moves in the direction indicated by the dotted line to block the light from the light source 16. Next momentary light receiving element 32b
Also detects the edge of the paper, but at this time the shutter remains closed. Then, when the head reverses and moves in the opposite direction, this time, it is first sensed that the light receiving element 32b is blocked by the paper, but at this time, the shutter remains closed and the light receiving element 31b next detects the paper edge. To open the shutter (move to the position indicated by the solid line).

When the head moves in the direction opposite to the arrow B, the shutter 30 is operated by the signal from the light receiving element 32b contrary to the above. As a result, the light from the light source 16 does not directly illuminate the light receiving element 12.

[0009]

However, in the above-described conventional apparatus, the amount of attenuation is 1 / thick for paper having a large amount of cellulose and high transparency (for example, tracing paper).
In some cases, the number does not reach 2 (bad S / N), and it is difficult to stably detect the edge of such paper. The present invention has been made in view of the above problems of the prior art. Even in the case of a paper having a large amount of cellulose and a high transparency, the S / N is improved so that the widthwise end of the paper is stabilized. It is an object of the present invention to realize a characteristic measuring device capable of detecting at any time.

[0010]

In order to solve the above-mentioned problems, the present invention provides a sheet-like object which has a predetermined width and which travels,
A first head and a second head, which are arranged to face each other with a predetermined gap sandwiching the sheet-like object, and reciprocate simultaneously in the width direction of the sheet-like object, and the first and second heads are provided with predetermined values. And a measuring element for irradiating the measuring light and the reference light of the wavelengths and measuring the water content of the sheet-like object from the amount of attenuation of the light, and the measuring element facing the first and second heads with the sheet-like object interposed therebetween. In a moisture device for a sheet-like object, which is provided with edge detecting means for detecting an edge in the width direction of the sheet-like object by the light-emitting element and the light-receiving element, the sheet-like object facing the light-emitting element and the light receiving element The presence or absence of the sheet-like object is detected based on the intensity of light of the light-emitting element passing through the polarizer and the sheet-like object.

[0011]

The polarizers are arranged so that their planes of polarization are parallel or shifted by about 90 °. When the planes of polarization are arranged in parallel without paper, the unpolarized light from the light emitting element passes through one polarizer to become linearly polarized light, and the linearly polarized light passes through the other polarizer as it is and is received. Illuminate the element. Similarly, if the planes of polarization are shifted by 90 ° without the paper, the linearly polarized light transmitted through one of the polarizers is blocked by the other polarizer and does not reach the light receiving element. In the presence of paper, the light that has passed through one polarization plane and becomes linearly polarized light illuminates the paper, but this linearly polarized light is scattered by the paper and the polarization is disturbed to become unpolarized light. A part of the light is transmitted through the other polarizer arranged parallel or shifted by 90 ° to become linearly polarized light and reaches the light receiving element. In this case, the difference (S / N) in the amount of light received by the light receiving element becomes large depending on the presence or absence of paper.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIG. The same elements as those in FIG. 5 are designated by the same reference numerals, and duplicate description will be omitted. In FIG. 2, reference numerals 50a and 50b denote polarizers provided to face each other with the paper 1 interposed therebetween.
Is provided after the LED and 50b is provided before the light receiving element.

In the above structure, the unpolarized light (A) emitted from the LED is incident on the polarizer 50a to be linearly polarized light (B), and hits the paper 1 (point C) and scattered light (non-polarized light: A '). Becomes This non-polarized light (A ') is the polarizer 50b.
Then, it becomes linearly polarized light and enters the light receiving element 31b (32b).

In this case, the polarizer 50 is emitted from the LED.
The light passing through a has a transmittance of 20 to 20 depending on the material of the polarizer.
It becomes 40%. For example, if the transmittance is 40%, the polarizer 5
If the planes of polarization of 0b are arranged in parallel, 40% of the light quantity passes through the polarizer 50b without being attenuated, and if they are arranged at right angles, the quantity of transmitted light becomes zero. Next, if there is a paper 1 and the polarizers are arranged in parallel, the transmittance of light by the paper is 1
If it is / 2, the light transmittance is 0.4 × 1/2 × 0.4 = 8.
%. Transmittance without paper 0.4 × 0.4 × 1
= 16%, and the light amount difference is 1: 2.

Further, when the paper 1 is provided and the polarizers are arranged at right angles, the light amount is attenuated to 8% in the light receiving element, but when there is no paper, the transmittance is zero, so the light amount difference (S / N). Is infinite in principle. FIG. 1 shows an embodiment of the present invention. The same elements as those of FIG. 3 are designated by the same reference numerals and their duplicate description will be omitted.
A polarizer 50 is provided between the EDs 40 and 40a and the paper 1 and between the paper 1 and the light receiving elements 31b and 32b arranged in the lower head.
The difference is that a, 50a ', 50b, 50b' are provided.

The polarization planes of the opposing polarizers are preferably parallel or right angles, but the accuracy is sufficient as long as a sufficient light amount difference that can be detected by the light receiving element is obtained. According to the above configuration, even if the sheet has a high degree of transparency, the difference in light amount between when there is no paper and when there is paper is more remarkable than in the prior art, and therefore stable paper edge detection can be performed.

[0017]

As described above in detail with reference to the embodiments, according to the moisture measuring apparatus of the present invention, the deflector is arranged so as to face the light emitting element and the light receiving element and sandwich the sheet-like object, and The presence / absence of a sheet-like object is detected based on the intensity of light from the light-emitting element that has passed through the child and the sheet-like object. Therefore, even though it is a transmission type optical sensor, even a thin sheet with small light attenuation has a large S / N signal. Therefore, it is possible to realize a measuring device which can stably detect the paper edge.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a moisture measuring device of the present invention.

FIG. 2 is an explanatory diagram for explaining the principle of the present invention.

FIG. 3 is an explanatory diagram showing a general configuration of a moisture measuring device.

FIG. 4 is a diagram showing a general configuration of a moisture measuring device incorporated in the upper and lower heads.

FIG. 5 is an explanatory diagram of a configuration showing a conventional example.

[Explanation of symbols]

 1 Paper 2 Upper head 3 Lower head 12, 31b, 32b Light receiving element 16 Light source 19 Irradiation window 22 Incident window 40, 40a Light emitting element (LED) 50a, 50a'50b, 50b 'Polarizer

Claims (1)

[Claims] 1. A sheet-like object that travels with a predetermined width, and a sheet-like object that is arranged so as to face the sheet-like object with a predetermined gap therebetween and that reciprocates simultaneously in the width direction of the sheet-like object. A first head and a second head; and a measuring means provided on the first and second heads for irradiating the measuring light and the reference light having a predetermined wavelength and measuring the characteristic of the sheet-like object from the attenuation amount of the light. A sheet-like object provided with end detecting means for detecting an end in the width direction of the sheet-like object by means of a light-emitting means and a light-receiving means provided to face the first and second heads with the sheet-like object sandwiched therebetween. In the characteristic device described above, a deflector is arranged so as to face the light emitting element and the light receiving element and sandwich the sheet-like object, and the sheet-like object is formed depending on the intensity of light of the light-emitting element passing through the polarizer and the sheet-like object. Check for the presence of objects A characteristic measuring device for a sheet-like object, which is characterized in that it is known.