JPS63193045A - Method for detecting flaw of paper - Google Patents

Abstract

PURPOSE:To enhance detection accuracy, by a method wherein a paper surface is allowed to run along a rotating mirror surface roll in a curved state, and a light source body and a light receiving means are provided in opposed relation to the curved surface and the change in the receiving quantities of the reflected lights from the paper surface and the mirror surface roll is detected. CONSTITUTION:Running paper 1 is guided on a roll 2 equipped with a reflecting surface and a curved bonded part 1a is formed along the surface of the roll 2, and a light source body 3 and a light receiving means 4 are arranged with respect to the bonded part 1a. An angle theta within a range of 45-80 deg. with respect to the tangential line passing the projection position of the light source body 3 above the roll 2 is respectively applied to the light source body 3 and the means 4. The roll 2 is rotated at the same speed as the running speed of the paper 1 and the reflected light due to the projection of light from the light source body 3 is received by the means 4, and a contamination part and a missing part are discriminated and detected from the change in the receiving quantity of the reflected light. By this method, a strong light source is not required and detection accuracy can be enhanced by a simple equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for detecting defects in paper, and is capable of accurately identifying and quickly detecting defective portions and soiled portions of paper in a paper making line or the like. It is intended to provide a method.

(Industrial application field) Technology for detecting defects such as paper defects and stains in paper manufacturing processes, etc.

(Prior art) Various methods have been used to detect defects (missing holes such as holes and soiled parts) in paper manufacturing processes such as paper making. To detect defects in the paper being taken, an optical method is used to reflect light emitted along the width of the paper from a light source on the paper surface, or to transmit it through the paper layer and detect it with a light receiver or imaging mechanism. things are being done.

(Problems to be Solved by the Invention) Among the conventional devices described above, the reflective type detects changes in light reflected from the defective portions (holes) and soiled portions of the running paper with respect to the good paper surface. Both the defective portion and the soiled portion are detected as the same amount of change in light amount with respect to the good paper surface, and there is a disadvantage that the defective portion and the soiled portion cannot be distinguished.

The transmitted light method eliminates the disadvantages of the reflected light method as described above.In this case, the amount of transmitted light increases in the defective area compared to the good paper surface, and the transmitted light in the soiled area decreases compared to the good paper surface, which is the opposite. Although it is possible to distinguish between defective areas and soiled areas because of the change in Transmission type devices suffer from insufficient light intensity, and their applications and conditions are limited. Furthermore, the advantage of the fluorescent lamp reflection method cannot be utilized to achieve high detection accuracy for paper surface dirt defects, which occur relatively frequently, and the detection accuracy for dirt defects inevitably becomes low.

"Structure of the Invention" (Means for Solving the Problems) Paper surfaces running along a rotatable mirror roll are curved and joined, a light source body and a light receiving means are disposed opposite to this curved and joined paper surface, and the light source body A method for detecting defects in paper, characterized in that the light reflected by the curved bonded paper surface and the mirror roll is received by the light receiving means, and a change in the amount of received light is detected.

(Function) By curve-joining the paper surface running along the rotatable mirror roll, the mirror roll rotates at the same speed as the running paper surface, and moreover, prevents wave motion of the paper surface at the measurement position.

A light source body and a light receiving means are arranged opposite to each other on the curved bonded paper surface as described above, and the light emitted from the light source body is reflected on the paper surface. Moreover, as mentioned above, the roll surface of the mirror roll that is press-bonded to the paper surface is also located at the same reflective surface level as the paper surface, so even at the defective hole, reflected light is formed in the same way as on the paper surface, and this is reflected by the light receiving means. The reflected light from the defect hole is received and detected in the same way as on the paper surface.

It is clear that the amount of reflected light at the stained area is sufficiently smaller than that at the paper surface, and on the other hand, the amount of reflected light obtained directly from the mirror surface of the roll at the defective area as described above is significantly larger than that at the paper surface. The amount of reflected light at the defective portion will be significantly different. That is, the amount of reflected light on the paper surface and the amount of reflected light on the soiled and defective portions are significantly different in any case, and the soiled portions and the defective portions are detected as being sufficiently distinguishable.

Further, the above detection results can be obtained without using a particularly high output light source.

(Example) To explain the specific embodiments of the present invention as described above, which are shown in the attached drawings, as described above, a running gill 1 in a paper making process is coated with a reflective surface such as a mirror surface. The paper 1 is guided onto the rolled roll 2 to form a curved joint 1a along the roll 2 surface, and this curved joint 1 is
A light source body 3 and light receiving means 4 are arranged with respect to a, and the light emitted from the light source body 3 is reflected at the curved joint 1a, and the light is received by the light receiving means 4.

Although any suitable light source body 3 may be employed, a preferable light source body is a fluorescent lamp as a tubular light source body, and in particular, a slit-shaped transparent portion is formed in an example of a tubular body called an aperture lamp. Efficient detection can be achieved by employing the following methods. As the roll 2, it is preferable to use one that has a mirror-like finish by plating, and this roll is provided in a floating manner and rotated on the same peripheral side as the running speed of the gi 1, or synchronized with the running speed of the gi 1. drive. The light source body 3 and the light receiving means 4 are disposed equiangularly opposite to each other with respect to the radial direction of the roll 2, that is, preferably at a angle of 45 to 80 degrees with respect to the tangent line C-.C passing through the projection position of the light source body 3 on the roll 2. The light source body 3 and the light receiving means 4 are each set to have an equal angle θ within the range of .

As the light source body 3, instead of the above-mentioned tubular light source body, the light emitted from the spot light source is transmitted using a rotating mirror.
It is also possible to use a device that scans sequentially in the width direction. As the light receiving means, a light receiving camera, a television camera, a line camera, and other photoelectric conversion elements are used.

A specific example of testing according to the present invention will be described below.

Paper manufactured with a weightage of 80 g/rd is 6 m/rd.
A mirror-like chrome-plated roll with a diameter of 26 cm is used as the roll 2 described above for a line that is run at a speed of
-c at an angle of 80°, and a light receiving camera as a light receiving means was set at the same angle of 80°, and the results of the inspection were as follows: .5 It is possible to accurately inspect even the point-like stains on the crane, and in addition, the amount of light received in the defective areas is 7 to 10 times higher than that on a good quality paper, whereas the stained areas are The amount of light is reduced to 178 to 115 of the amount of light obtained on the paper, and can be clearly distinguished.

On the other hand, when inspecting using the conventional transmitted light method without using the reflective roll 2 described above, the light source described above is insufficient in light intensity for the same paper quality as described above, and a light source of several hundred watts is used. As mentioned above, it is not possible to properly detect a soiled part even if the method uses reflected light, and it is not possible to distinguish between a soiled part and a defective part in the case of the reflected light method.

``Effects of the Invention'' According to the present invention as explained above, it is possible to clearly distinguish between the soiled part and the missing part of the paper before shipping, and moreover, without using a particularly powerful light source. This invention has the effect of being able to effectively achieve the above-mentioned detection purpose with simple equipment using a general fluorescent lamp method, and is a highly effective invention from an industrial perspective.

[Brief explanation of the drawing]

The drawings show the technical content of the present invention, and are explanatory diagrams showing an outline of equipment for implementing the present invention. In this drawing, 1 is a paper, la is a curved joint thereof, 2 is a reflective roll, 3 is a light source, and 4 is a light receiving means.

Claims (1)

[Claims] Paper surfaces running along a rotatable mirror roll are joined together in a curved manner, and a light source body and a light receiving means are provided oppositely to the curved joined paper faces, and light emitted by the light source body is reflected by the curved joined paper surface and the mirror roll. A method for detecting defects in paper, characterized in that the above-mentioned light receiving means receives light and detects a change in the amount of received light.