JPH04298443A - Roll end position control method and device - Google Patents

Abstract

PURPOSE:To provide a roll end position control method and a device which can facilitate movement and setting of a sensor even if the width of a web changes and can make accurate control even if the web is a film. CONSTITUTION:An infrared projector 1 is mounted in a space located slantly upward from a roll 2 so that no external disturbance element may enter the field of view of a camera 3, the projector may emit its rays and a picture image may be picked up by the camera 3 which has a tow-dimensional image sensor. The picture image is scanned from the left to the right by an image processing means 5, and binary level is optimized in a binary circuit 6 at the time of conversion from analog to digital by inputting web quality information in accordance with the web quality of the roll 2 so that a picture image which excels in N/S may be obtained. Next, the lateral travel speed of the roll is switched in two steps by a hydraulic unit 9 to control it so that it stops with stop accuracy within + 0.5mm.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] A roll end position control method in which a long flexible support (hereinafter referred to as a web) is continuously fed out, and the end position of the roll is kept constant to perform feeding and joining. The present invention relates to a roll end position control method and apparatus, and in particular to a roll end position control method and apparatus suitable for handling a wide variety of webs with different widths.

0002

[Prior Art] A conventional method and device for aligning the end face of a roll involves blowing a jet of air perpendicularly to the end face of the web from one side, and placing an air pressure detector on the opposite side to detect horizontal deviation of the web position. There is a method of detecting the problem and correcting the web running path depending on the degree of the problem, or a method of detecting it with a one-dimensional image sensor using infrared rays and correcting it by moving a winder or a feeder.

0003

[Problem to be Solved by the Invention] However, with the device using the former air pressure measurement control method, when the width of the web changes and the position of the web passage shifts, it takes time and effort to move and set the detection device, making adjustment inconvenient. Moreover, the air pressure detection section cannot be installed in the rolled state before the web is sent out. In addition, when using the latter one-dimensional sensor infrared detection device, it is necessary to use materials with high infrared reflectance on the web surface, such as photographic paper (p
Aper) has a strong reflectance and can be detected, but a film with a high transmittance has a problem in that it cannot be detected due to the infrared rays passing through it. The purpose of the present invention is to solve the above-mentioned conventional problems, and to provide a sensor at the end of a roll that can be easily moved and set even when the width of the web changes, and that can be precisely controlled even when the web is a film with high transmittance. An object of the present invention is to provide a position control method and device.

0004

[Means and Effects for Solving the Problems] The above object of the present invention is to install an infrared projector on the upper part of the web just before the roll is sent out so as to illuminate the web obliquely toward either the left or right end of the web. An image of the web end is captured by an optical system having a two-dimensional image sensor installed directly above the web end to which the infrared rays are irradiated, and an image processing means is used to determine the correct end position from the image. A method for controlling the position of a roll end, characterized in that the position is controlled by detecting the displacement from the end position and controlling the position of the roll by changing the horizontal movement speed of the roll in two stages, high and low. It has an infrared irradiator that irradiates the end obliquely, a two-dimensional image sensor camera directly above it, and an image processing device that processes the image from the two-dimensional image sensor, and moves the roll left and right based on instructions from there. 1. A roll end position control device comprising: a device for controlling a roll end position; achieved by

The roll end position control method and apparatus of the present invention include an infrared projector installed above the web just before the roll is sent out so as to illuminate the web obliquely toward either the left or right end of the web, and an infrared projector installed directly above the web. By setting an optical system having a two-dimensional image sensor installed on a single axis that supports both, changes in web width can be easily handled. Webs to which the web end position control method and apparatus of the present invention can be applied include photographic paper coated with waterproof coating (hereinafter referred to as WP paper), as well as polyethylene terephthalate (hereinafter referred to as PE paper).
Triacetylcellulose (hereinafter referred to as TAC)
It can be applied to a wide variety of rolls of films with different infrared reflectances, such as In the present invention, by irradiating the web obliquely with an infrared projector at the upper center of the web toward the edges of the web, the reflection makes it clear to distinguish between the edges and the outside, and furthermore, the outside part This is because it is easy to distinguish the end portion by appearing black in the field of view when it is in the shadow, and the angle of the oblique angle is preferably about 30°. In conventional one-dimensional image sensors, the only object to be detected is photographic paper, because photographic paper has the highest surface reflectance and has the property of providing stable diffusely reflected light. However, when the detection target is PET and image measurement is performed using a two-dimensional image sensor as shown in Figure 2, the threshold (
There is a difference of 10 in the binarization level, and photographic paper is more advantageous, but PET can also be measured, and TAC
In the case of , the reflectance is intermediate between these and can of course be used. Therefore, in the present invention, the detector is changed from one-dimensional to two-dimensional, and the side surface of the roll is imaged in an area pattern, and then the edge is detected, thereby eliminating the detection failure due to the difference in reflectance depending on the type of web. In the case of detecting the position of the end of a roll according to the present invention, the roll surface has a curvature, and the reflected light from the projector is distributed depending on the location. Also, due to the unevenness of the surface,
The reflected light is not of uniform intensity. When they are uniformly captured by a camera, a binarized image of the roll end face image as shown in FIG. 3 is created. The roll end face Y indicated by the dotted line does not clearly appear on the screen, and image boundaries as indicated by a, b, and c surrounded by solid lines are obtained. When a one-dimensional image sensor is used, when a detection line is drawn at A, a line corresponding to point B on A appears, and the edge is unclear. Particularly in the case of a film with a high transmittance, it is difficult to determine the true edge, so there is a drawback that the end surface position is determined to be slightly inside the web. The image obtained by the two-dimensional image sensor of the present invention has a shape that partially extends to the right side in FIG. This is recognized as the position of the roll end face by complementing the missing part) and performing image processing to treat it as a straight line. Through such processing, the position of the end face can be accurately identified even from the reflected light of something with curvature, such as a roll. In addition, in order to improve the winding appearance, approximately 1
Knurling is carved with a width of 0mm. This may diffusely reflect the infrared light that is emitted to detect the end face and input it to the camera, which may cause it to be mistakenly recognized as an end face. For this reason, the scanning direction of the image is run from the outside of the edge toward the center of the roll, and the first point of change is taken as the end face data, thereby avoiding misrecognition of the end face due to diffused reflection from the knurling. Furthermore, by setting the binarization level during analog to digital conversion to an optimum value determined in advance according to the product type, an image with a good S/N ratio can be obtained. The end surface stop position determined by alignment of the roll end surface varies depending on the coating position reference of the coating machine and the base width. In the apparatus using the method of the present invention, the camera is placed on a uniaxial movement mechanism and moved so that the center of the camera is on the target stop position in advance, so that it can cope with changes in the end position due to changes in the web width. There is. In the roll end position control method and apparatus of the present invention, since approximately 200 msec is required for image processing, the roll is initially moved horizontally at a high speed, and the roll is moved horizontally at a low speed in the vicinity of the stop position. Maintained accuracy and shortened position control time.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained with reference to the drawings. When viewing the roll end face as shown in FIG. 1, it is desirable that no disturbing elements (chucking nose, winding core, etc.) enter the camera field of view. By installing the infrared light projector 1 obliquely upward on the top of the web just before the roll 2 is sent out, the partial core 4 other than the end face becomes a shadow of the light, which illuminates the two-dimensional image sensor installed directly above. It is not input as an image to the camera 3 that has the camera 3. The image received by the camera 3 is scanned in the scanning direction from left to right by the image processing means 5, and also converted to a binary level by the binarization circuit 6 during analog to digital conversion according to the type of web in the roll 2. By incorporating quality information and optimizing, images with good S/N can be obtained. Next, this is put into the deviation calculator 7 and compared with the set value, the deviation is calculated, and the high speed movement command 8 is activated to move the hydraulic unit 9. Next, regarding the two-step switching of the left and right moving speed of the roll, compared to the conventional one-dimensional image sensor camera system, the time required for detection is approximately 20 minutes due to the simple image processing applied to end face detection.
Although it is twice as slow (10msec. → 200msec.),
However, it is necessary to complete the alignment of the roll end faces within the conventional time and maintain the current stopping position accuracy. Therefore,
The speed of the hydraulic unit 9 that moves the roll left and right is changed from the conventional 1st speed to 2nd speed (high speed, low speed), and the position is corrected by changing the speed to low near the stop position (±8 mm) and high elsewhere. The aim was to shorten the total time. That is, high speed: 17 mm/sec, low speed: 4.5 mm/sec
c, even if the roll end face position is deviated by 100 mm from the specified position, the stop position accuracy will be ±0.0 within 10 seconds.
It is now possible to stop within 5mm.

[0007]

[Effects of the Invention] By using the roll end position control method and device of the present invention, accurate position control is possible even when the type of web is film, and even when the web type is film, by using a two-dimensional image sensor. It has become possible to respond quickly, and by using a two-stage high/low speed switch for control speed, it has become possible to perform control accurately within ±0.5 mm.

[Brief explanation of the drawing]

FIG. 1 is a front view and a control circuit diagram of an embodiment of the roll end position control method and device of the present invention.

[Fig. 2] Graph of binarization level versus projection power for photographic paper and PET when using the roll end position control method of the present invention.

[Fig. 3] An image showing the relationship between image pattern shapes a, b, and c obtained by a two-dimensional image sensor and the end of the roll, and the deviation between point B and the end of the roll according to detection line A when a primary image sensor is used. Comparison chart.

[Explanation of symbols]

1 Floodlight 2 Roll 3 Camera 4 Core 5 Image processing means 6 Binarization circuit 7 Deviation calculator 8 High-speed movement command 9 Hydraulic units a, b, c Two-dimensional image sensor images A to B One-dimensional image sensor image

Claims (2)

[Claims] [Claim 1] An infrared projector is provided on the top of the web just before the roll is sent out so as to irradiate the web obliquely toward either the left or right end of the web, and directly above the end of the web where the infrared rays are irradiated. An optical system equipped with a two-dimensional image sensor installed in the image captures an image of the web end, and an image processing means determines the correct end position from the image.The web end is detected by an image processing means and the magnitude of displacement from the end position is determined A method for controlling the position of a roll end, characterized in that the position of the roll is controlled by switching the horizontal movement speed of the roll in two stages, high and low. 2. An infrared irradiator for obliquely irradiating the end of the web on the top of the roll, a two-dimensional image sensor camera directly above the roll, and an image processing device for processing images from the two-dimensional image sensor; 1. A roll end position control device comprising: a device for moving the roll left and right based on a command from the roll end position control device.