JP2000180117A - Inspection device for eccentricity of winding paper roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine an eccentric amount of a winding paper roll by picking up an image of an end plane of a paper tube of the roll with the roll rotated to determine a center position of the roll using a roll holding means rotatably holding a holding roll and an image pickup means arranging an optical axis in a photographing optical system in parallel to a shaft direction of the holding roll. SOLUTION: When a winding paper roll 1 is mounted on a holding roll 3, the center of an end plane of a paper tube 2 is located on a vertical line of a midpoint of a distance between axes of the holding rolls 3. A first actuator 5 is activated based upon data of a distance sensor 7 to move a camera 4 up to a high position where an image of the end plane of the paper tube 2 can be picked up. A moving amount of the camera 4 is measured as a distance from a reference position. The reference position is already known from a relation for the midpoint of the distance between axes of two pieces of the holding rolls. Then, a second actuator 6 is activated to move the camera 4 up to a position where the image of the paper tube 2 can be picked up. The center coordinate of the tube 2 is computed by image processing for the position data of the image and an eccentric amount is determined from a distance between the core center of the roll 1 and the holding roll 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for inspecting a roll of paper roll manufactured at a paper mill.

[0002]

2. Description of the Related Art In a paper mill, in order to improve the productivity of paper, the paper is usually made in a width of 4 m or more and wound up in a roll form at the exit of the paper machine. Such wide rolls of paper rolls have problems in transportation, the width of paper processing machines such as printing machines for consumers, etc. Cannot be shipped to factory. Therefore, the paper mill cuts it into a suitable small width with a slitter, shortens the winding length if necessary, and rewinds it into a small roll of a size suitable for the processing machine such as the printing machine of the customer before shipping. I do. And
When rewinding into a small volume, a paper tube (core) is used as the core.

[0003]

A roll of take-up paper (hereinafter simply referred to as a paper roll) which has been rewound into a small roll is usually supplied to a printing machine in a printing factory while rewinding it in its original shape. . However, if the cross-sectional shape of the paper roll is not a perfect circle and is eccentric, adverse effects such as fluttering, paper cutting, and printing misalignment in the printing press are produced. Therefore, the paper mill inspects the eccentricity of each rolled paper,
Only eccentricity less than a certain amount is shipped.

The inspection of the eccentricity is usually performed by a manual method described below. That is, a cylindrical or conical chucking hardware called a nose is inserted into a core (paper tube) of a paper roll, and a graduated scale is rotated around the core so as to cover the entire outer circumference of the paper roll. The radius from the center is measured, and if the difference between the maximum value and the minimum value is equal to or more than a certain value, the shipment is stopped as a defective product.

However, the above-described manual method requires much time and labor, and requires a gap between the nose and the core for rotating the nose. A large gap causes a measurement error, and a small gap causes a measurement error. There is a problem that the rotation of the nose cannot be performed smoothly and the measurement work is stagnated.
Further, since the radius is measured by visually checking the scale, there is also a problem that a human measurement error occurs and the defective paper roll is overlooked.

[0006]

As a technical means for achieving the above object, a roll paper roll eccentricity inspection apparatus according to the present invention is provided with a pair of rotating members arranged in parallel at appropriate intervals. It comprises a freely supporting roll, roll supporting means for rotatably supporting the supporting roll, and photographing means in which the optical axis of the photographing optical system is arranged in parallel with the axial direction of the supporting roll. The support rolls do not necessarily have to be of the same diameter and do not necessarily need to be installed horizontally,
If the rolls having the same diameter are installed horizontally, the structure of the apparatus is simple, and no complicated operation is required when adjusting the positional relationship between the photographing means and the support rolls. Therefore, the following description
The description will be made assuming that the support rolls having the same diameter are installed horizontally. The take-up paper roll to be subjected to the eccentricity inspection is placed and supported on the pair of support rolls, and the side of the take-up paper roll is rotated once by the support roll by the photographing unit. An appropriate number n of the end portions of the paper tube of the take-up paper roll (the base portion if a base is provided) are photographed. As the number n of images to be photographed increases, the accuracy of the eccentricity inspection increases as the number n increases. However, it is necessary to take pictures at substantially equal intervals, such as taking pictures at a constant angular interval.

Next, the center coordinates Q (Xk, Yk) of the paper tube are obtained from the image of the end portion of the paper tube captured by the photographing means (where k = 1, 2, 3,..., N); Its center coordinate Q
With the center at (Xk, Yk), the distance between a predetermined contact point of one of the support rolls (for example, 3A in FIG. 4) from the pair of support rolls and the center coordinate of the paper tube is defined as a radius. The radius Lk of the virtual circle to be calculated is obtained. The meaning of the virtual circle is that the side surface of the roll of paper roll to be subjected to the eccentricity inspection is a perfect circle centered on the axis of the paper tube (hereinafter, also simply referred to as the center of the paper tube or the center of the paper tube). 7 is a diagram of the outer periphery of the take-up paper roll in the case of performing the operation.

The radius Lk of the virtual circle is an approximate value of the distance between the center of the paper tube of the take-up paper roll to be subjected to the eccentricity inspection and one point on the outer periphery of the take-up paper roll, as described below. That is, the distance between the center of the paper tube of the take-up roll and one point of the outer peripheral portion of the take-up roll cannot be calculated unless the exact coordinates of the contact point between the take-up roll and the support roll are known strictly. However, the eccentricity of the take-up paper roll is about 5 mm at the maximum even for a roll having a diameter of 1 m, so that the calculated value of the eccentricity does not greatly differ even if the coordinates of the contact point between the virtual circle and the support roll described above are used.

The center position of the paper tube and the position of the axis of the selected one of the support rolls 3A are displayed in the same coordinate system, the center coordinate of the paper tube is Q (Xk, Yk), and the radius of the support roll is r. ,
Assuming that the coordinates of the axis of the support roll 3A are (a, b), the radius Lk of an imaginary circle Lk (k = 1) which is an approximate value of the distance between the paper tube center of the take-up roll and one point on the outer periphery of the take-up roll. ,
2,3, ..., n) is

(Equation 1) Can be obtained by If the eccentricity of the paper roll is defined as the difference between the maximum diameter and the minimum diameter of the same roll, the difference between the maximum value and the minimum value of Lk is obtained to approximate the eccentricity of the paper roll. The value is obtained.

In order to calculate the value of Lk, it is necessary that the positional relationship such as the distance between the origin of the photographing means and the origin of the support roll is known. On the other hand, there are various external dimensions of the roll of paper roll for which the amount of eccentricity is to be measured. If the height position of the roll supporting means is kept constant, if the roll diameter of the take-up paper roll to be measured greatly changes, the height of the center of the paper tube changes. If the photographing means can be moved up and down, it is possible to cope with a change in the height of the paper tube center. When the photographing means is moved up and down, for example, if a pulse motor is used as the elevating means, the elevation distance of the origin of the photographing means can be automatically and accurately known.

Therefore, for example, a CCD camera is used as a photographing means, and the side surface of the support roll is photographed substantially at the center of the imaging surface of the CCD camera, and the side image of the support roll is viewed on a television monitor, or the photographed support roll is used. By processing the image of the roll, the coordinates of the axis of the support roll in the coordinate system of the imaging surface of the CCD camera are obtained, and the origin (or the origin) of the imaging surface of the CCD camera is adjusted to match the coordinate of the axis of the support roll. (0,0) is corrected.

When the CCD camera is moved from the photographing position of the support roll by u and v in the X-axis and Y-axis directions by the above-described moving means such as the pulse motor, the moving distance depends on the moving distance. If the coordinates of the origin of the imaging surface of the CCD camera are automatically corrected to (u, v), all the images taken by the CCD camera can be used as the origin of the support roll. (0,0)
Can be displayed in the reference coordinate system. As described above, when the coordinates of the center of the paper tube center of the take-up paper roll photographed by the CCD camera are displayed in the reference coordinate system in which the axis of the support roll is the origin (0, 0), the Lk is:

(Equation 2) Can be calculated.

In the above-described method and apparatus for measuring the amount of eccentricity, the origin of the reference coordinate system is set at the position of the axis of the support roll. However, in the present invention, the coordinates of the center position of the support roll and the roll paper are used. The origin of the reference coordinate system can be arbitrarily determined since it is only necessary to be able to represent the coordinates of the roll at the center of the paper tube in the same coordinate system.

[0014]

FIG. 1 is a side view of a roll paper eccentricity inspection apparatus according to an embodiment of the present invention. The width and the winding length are in accordance with the requirements of the consumer. The take-up paper roll 1 is placed and supported on a support roll 3. As shown in FIG. 3, the support roll 3 is composed of a pair of rotatable support rolls 3A and 3B having the same diameter and arranged at an appropriate distance, and the rotation axis of the support rolls 3A and 3B. Are arranged in parallel in the same horizontal plane. Then, one or both of the support rolls 3A and 3B are rotated by the power of a drive shaft (not shown).

A photographing camera 4 having an optical axis which is parallel to the axis of the paper tube 2 of the paper roll 1 is provided facing the end of the paper tube 2 of the paper roll 1. The camera 4 is supported by a first actuator 5 with a support roll 3A,
It is possible to move up and down exactly the distance specified along a vertical line passing through the midpoint of the inter-axis distance of 3B. The approximate diameter of the take-up paper roll is measured in advance by a distance sensor 8 using infrared rays or ultrasonic waves, and the amount of elevation of the camera 4 is adjusted by the first actuator 5 so that the above-described paper tube can be photographed. Is instructed.

The upper part of the first actuator 5 is supported by a second actuator 6, and the first actuator 5 is movable along a direction parallel to the axial direction of the support roll 3. Accordingly, the movement of the actuators 5 and 6 allows the camera 4 to approach and separate from the end of the paper tube 2 so that the end can be reliably contained in the photographing range. Further, as described above, the first actuator is provided with a distance sensor 7 such as an infrared sensor for detecting the distance to the end surface of the web roll 1, and the upper portion is provided with an approximate outside of the web roll. A distance sensor 8 for detecting a diameter is provided.

FIG. 2 and FIG. 3 show a schematic structure when the eccentricity inspection device for the roll of roll is mounted.
The smallest diameter roll 1A and the largest diameter roll 1B that can be inspected by this eccentricity inspection device.
And are written together. When these take-up paper rolls 1 are placed on the pair of support rolls 3A, 3B, the paper tube 2 of the take-up paper roll 1 is irrespective of its outer diameter.
Is located above the midpoint of the distance between the axes of the support rolls 3A and 3B. The take-up eccentricity measuring device is arranged at both ends of the take-up paper roll. For this reason, the eccentricity inspection of the paper roll 1 can be performed at both ends of the paper roll 1.

Further, position data captured by the camera 4 and data relating to the elevation distance of the camera 4 and the like are input to an arithmetic unit (not shown) and used for calculation of the above-described and later-described mathematical expressions and the like. The operation of the roll paper roll eccentricity inspection apparatus according to this embodiment configured as described above will be described below with reference to FIG.

The paper roll 1 to be inspected is fed to the eccentricity inspection device by a transport device (not shown), and is placed on the support roll 3. The center of the end face is located substantially on the vertical line at the midpoint of the distance between the axes of the support rolls 3A and 3B.
Based on the data from the distance sensor 8, the first actuator 5 is operated to move the camera 4 up and down to a position where an image of the end face of the paper tube 2 can be captured. At this time, the movement amount of the camera 4 is measured as a distance from the reference position. This measurement can be easily recognized by, for example, counting the number of pulses of the first actuator 5 using a pulse motor or providing an encoder or the like.

The reference position is a known position in relation to the midpoint of the distance between the axes of the two support rolls. By measuring the amount of movement of the camera 4, the camera 4 and the support roll 3 are measured.
Can be recognized with respect to the axis. Next, the second actuator 6 is operated to position the camera 4 at a position where the image of the paper tube 2 can be captured. At this time, the camera 4 is moved with reference to the distance to the paper roll obtained by the distance sensor 7.

When the camera 4 captures an image of the end face of the paper tube 2, the coordinates of the center Q of the paper tube 2 are obtained by processing the position data of the image of the paper tube (for example, a circle). (The method of calculating the center of a circle passing through any three points on the circumference).

Although the origin of the reference coordinate system can be determined arbitrarily, the approximation of the distance between the center of the paper core of the take-up paper roll and one point on the outer peripheral portion of the take-up paper roll has been described. In order to obtain the value of Lk, the coordinates of the axis of the support roll 3A and the coordinates of the center of the paper tube of the take-up paper roll in an arbitrarily determined reference coordinate system must be obtained.

Alternatively, the axis of the support roll 3A is used as the origin of the reference coordinate system, and the coordinates of the center of the paper tube of the take-up paper roll in that coordinate system must be obtained. However,
Since the end of the support roll 3A is normally supported by a bearing, it is difficult to photograph the entire side surface of the support roll, and it is also difficult to set the origin on the imaging surface of the camera. Further, even if the origin of the reference coordinate system is set at another position, it is difficult to obtain the coordinates of the axis of the support roll 3A. Therefore, an example of an alternative method is described below.

In FIG. 4, a point P indicates an origin P (0, 0) of a reference coordinate system formed by the imaging range of the camera 4 and is a predetermined point in the imaging range, for example, the optical axis of the camera 4. And the intersection of the imaging plane. The actuator 5 as an elevating means of the camera 4 manufactures this inspection apparatus so as to ascend and descend along a vertical line passing through the midpoint between the axes of the support rolls 3A and 3B.

Next, the paper rolls of a perfect circle whose radius is a known value L0 and are not eccentric at all are supported by support rolls 3A and 3B.
The paper tube is placed on the top, and the paper tube is photographed by the camera 4 while making one rotation. If a wrapping paper roll of a true circle that is not eccentric is not prepared, a round disk with the same size as the take-up roll circle and a mark at the center position may be used instead. .

If the side of the paper roll is a perfect circle,
The position of the coordinates of the center of the paper tube on the imaging surface of the camera does not change due to the rotation of the web roll. Since the coordinates of the center of the roll of the roll L0 are on a vertical line passing through the midpoint of the distance between the axes of the support rolls 3A and 3B, the center position of the roll of the roll on the imaging surface of the camera is used as a reference. The coordinates are corrected with the origin P (0, 0) of the coordinate system. By correcting in this manner, even if the camera is moved up and down by the actuator 5 in the vertical direction, the X of the fixed point arbitrarily set on the imaging plane of the camera in the reference coordinate system is obtained.
The coordinates do not change.

The coordinates (a, b) of the axis of the support roll 3A in the reference coordinate system can be obtained without photographing with a camera for the following reasons. That is, the absolute value of a is 1/2 of the distance between the axes of the support rolls 3A and 3B, and b is calculated from the known value L0 and the known roll diameter r by the following equation. Since a and r are the design dimensions of this device, they are naturally known numerical values.

(Equation 3)

Next, the principle of calculating the amount of eccentricity of the roll of paper roll used for eccentricity inspection by the eccentricity measuring device described above will be described. In FIG. 4, a circle C indicated by a dotted line is an outer peripheral line of a roll of a perfect circle having a radius L0 used to determine the origin of the reference coordinate system earlier, and the coordinates of the center of the circle in the reference coordinate system are as follows. P (0,0). A circle D indicated by a solid line is an outer peripheral line of the roll of paper roll to be subjected to the eccentricity inspection, and the coordinates of the center Q of the paper tube taken by the camera 4 in the reference coordinate system are (Xk, Yk) (where k is k). = 1
2,3, ..., n). Since the image D of the take-up roll paper tube used for the eccentricity inspection is captured by the camera 4,
The coordinates (Xk, Yk) of the center Q can be obtained as coordinates in the reference coordinate system.

Since the coordinates of the axis of the support roll in the reference coordinate system are (a, b), an approximate value Lk of the distance between the center of the paper tube of the take-up roll and the contact point between the support roll is obtained.

(Equation 4) Since the actual paper roll used for the eccentricity inspection is eccentric, the contact point in contact with the support roll 3A is slightly different from the imaginary circle E which is a perfect circle centered on the point Q in FIG. That is, since the virtual circle E is a perfect circle, the support roll 3A
Is on a straight line connecting the center point Q of the virtual circle and the center of the axis of the support roll 3A. However, in the case of an eccentric winding paper roll, it may be difficult to define the center point itself, and even if it is defined, the center is not necessarily located in a direction orthogonal to the tangent line. It may be slightly off the contact. However, since the amount of eccentricity is very small, this difference can be ignored, and the length of Lk in FIG. 4 can be regarded as the distance between the center Q of the paper tube and the outer peripheral line of the take-up paper roll.

When the support rolls 3A and 3B are rotated and the take-up paper roll 1 is rotated by an appropriate angle, the center Q of the paper tube 2 is at a fixed position when the take-up paper roll 1 is eccentric. However, the position is shifted while turning irregularly according to the rotation of the take-up roll 1. However, each time the take-up paper roll 1 is rotated by an appropriate angle, as described above, the coordinates of the center Q of the paper tube in the reference coordinate system and the contact point with the virtual circle E contacting the support roll 3A about Q are used. , An approximate value of the distance between the center of the core of the take-up paper roll 1 and the contact point between the support roll 3A can be obtained.

Since the amount of eccentricity of the paper roll 1 can be obtained from the difference between the maximum value and the minimum value of these approximate values, for example, the paper rolls are supported by the support rolls 3A, 3B at an angular interval of 5 degrees. If the paper tube 2 is sequentially photographed by the camera 4 while rotating the above, n = 72 Lk values can be obtained.
Then, the difference between the calculated maximum value and the minimum value of Lk of the take-up paper roll 1 may be defined as the amount of eccentricity.

When the take-up paper roll 1 is rotated by an appropriate angle, when the take-up paper roll 1 is eccentric, the center Q of the paper tube 2 becomes irregular according to the rotation of the take-up roll 1. If the position is shifted while turning, and one rotation is made, it returns to the original position. If the coordinate data of the point Q is appropriately numbered, the locus of the point Q due to the rotation of the winding roll 1 draws a curved figure.
The maximum value of the distance between the points on the curve figure is L
It should not be much different from the difference between the maximum value and the minimum value of k. Therefore, the maximum value of the distance between the points on the curved figure may be calculated and calculated by an arithmetic processing unit (not shown) and used as an approximate value of the eccentricity.

In the operation described above, the position data, the amount of movement of the actuator, and the data of the rotation angle of the take-up roll 1 captured by the camera 4 are input to an arithmetic processing unit (not shown), and the processing unit The calculation shown in the equation is performed, and a drive signal for rotating the support rolls 3A and 3B is sent from the processing device, and the roll paper 1 is rotated at a predetermined angle. In addition, if the image captured by the camera 4 is displayed on a monitor, and the operation is performed while visually recognizing the monitor, the operation becomes easier. FIG.
7 shows results relating to the maximum eccentricity and the time required for measurement when the eccentricity of the roll 1 is measured by the web eccentricity inspection apparatus according to the invention and the conventional inspection method. In the same figure, Example 1 shows the result of measurement on a roll paper 1B having a diameter of 1200 mm by the eccentricity inspection apparatus for roll paper of the present invention, and Example 2 shows the result for a roll paper 1A having a diameter of 950 mm. The result of the measurement is shown.

In Comparative Examples 1 and 2, the amounts of eccentricity of the paper roll 1B and the roll 1A were manually increased by using a conventional nose which had been conventionally used. Shows the results of the measurement. In Comparative Example 3 and Comparative Example 4, the eccentricity of the winding paper roll 1B and the winding paper roll 1A was carefully and almost accurately measured by hand using a nose adjusted and prepared according to the core 2. Is shown. Comparing the measurement results shown in FIG. 5, the maximum eccentricity measured by the eccentricity inspection apparatus according to the present invention is a value close to the maximum eccentricity measured almost accurately by the hands shown in Comparative Examples 3 and 4. As a result, almost satisfactory data could be obtained. In addition, the measurement time can be reduced to about one-fifth that of the conventional method, which is advantageous in terms of the measurement time.

[0035]

As described above, according to the eccentricity inspection apparatus for a take-up paper roll according to the present invention, the photographing means for photographing the paper tube is provided, and the arithmetic processing unit , The amount of eccentricity of the take-up paper roll is obtained, so that the amount of eccentricity can be inspected without manual operation, and the occurrence of an artificial measurement error can be eliminated. In addition, since the inspection can be performed without contacting the roll of paper, the inspection can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic front view for explaining a schematic structure of a roll paper roll eccentricity inspection apparatus according to the present invention.

FIG. 2 is a front view showing a schematic structure in a case where an eccentricity inspection device for a take-up paper roll according to the present invention is mounted.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a diagram for explaining the principle of calculating the amount of eccentricity by the wrapping paper roll eccentricity inspection apparatus according to the present invention;

FIG. 5 is a diagram comparing a result obtained by measuring with an eccentricity inspection device for a roll of paper roll according to the present invention, a result obtained by a conventional method, and a result obtained by carefully measuring manually.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 roll paper roll 2 paper core (paper tube cap) 3 roll support means 3A support roll 3B support roll 4 camera (photographing means) 5 actuator 6 actuator 7 distance sensor 8 distance sensor C circumference of roll L of radius L0 Line D Peripheral line of the take-up paper roll used for inspection E Virtual circle Lk Radius of virtual circle P Origin of reference coordinate system Q Center of paper tube of roll used for inspection

Claims (4)

[Claims] 1. A roll support for mounting and supporting a pair of support rolls arranged in parallel at appropriate intervals and a take-up paper roll for eccentricity inspection, and rotatably supporting the support rolls. Means, and a photographing means in which the optical axis of a photographing optical system is arranged in parallel with the axial direction of the support roll at a position where the paper tube of the take-up paper roll can be accommodated in a photographing range. While rotating the take-up paper roll, an appropriate number of images of the end of the paper tube of the take-up paper roll are taken by the above-mentioned photographing means, and the image of the end of the paper tube captured by the above-mentioned photographing means is taken out of the end of the paper tube. A center position is determined, and an eccentricity is measured from a difference between a maximum value and a minimum value of a distance between a center of the paper tube and a center position of one of the shafts of the pair of support rolls. An eccentricity inspection device for paper rolls. 2. A roll support for mounting and supporting a pair of support rolls arranged in parallel at appropriate intervals and a take-up paper roll for eccentricity inspection, and rotatably supporting the support rolls. Means, and a photographing means in which the optical axis of a photographing optical system is arranged in parallel with the axial direction of the support roll at a position where the paper tube of the take-up paper roll can be accommodated in a photographing range. While rotating the take-up paper roll, an appropriate number of images of the end of the paper tube of the take-up paper roll are taken by the above-mentioned photographing means, and the image of the end of the paper tube captured by the above-mentioned photographing means is taken out of the end of the paper tube. An eccentricity inspection apparatus for a take-up paper roll, wherein a center position is obtained, and an eccentricity amount is measured from a maximum value of a distance between the center positions of the paper tubes. 3. The photographing means is capable of moving up and down in a direction passing through a midpoint of a distance between the axes of the support rolls and perpendicular to a straight line connecting the axes. An eccentricity inspection device for a roll of rolls according to any one of the above. 4. The eccentricity inspection apparatus for a paper roll according to claim 1, wherein the photographing means is a CCD camera.