EP2093173B1 - Method and device for detecting orientation characteristics on a web of material - Google Patents

Description

Technical area

This document relates to apparatus and methods for detecting orientation features on a web

background

Web processing systems are used in the processing of web-shaped materials. For example, material webs can be fed from a winding of a machine, processed and subsequently rewound, whereby different position errors can occur. For example, to regulate the lateral offset of a web of material, appropriate regulatory devices may be used.

FIG. 1A and FIG. 1B show such a regulation device in which the material web 100 of the width B undergoes a four times 90 ° deflection by means of a rotary frame system. The material web is deflected via an inlet roller 101 and fed via an inlet length L _{1 to} a pivotable positioning frame 105 with two deflection rollers 102, 103. With the help of the pivotable positioning frame 105 can then bring about a lateral material web correction. The material web is thereby pivoted about the pivot point 106 by an angle α. The material web is then fed via an outlet length L _{2 of} an outlet roller 104. In the area of the outlet length L ₂ , a sensor device 170 may be arranged. Due to the pivoting of the material web by an angle α, the material web in the region of the outlet length L _{2 may have} a corresponding deviation from a material web plane S provided.

This deviation can influence the measurement result of a sensor located in the area of the outlet length. In an exemplary device for web guiding, an additional roller may be located in the region of the outlet length in order to correct the deviation and to keep the material web in the intended material web plane S in the further course of the outlet length. Thus, a constant distance of the material web from the sensor can be maintained in the further course of the outlet length and it is possible to accurately measure the material web with conventional sensors. However, the web can be warped or wrinkled by the backing roll. Also, the use of an additional roller can be costly.

US-A-5,354,992 discloses a system for generating a position correction error signal indicative of the lateral offset of the center of a strip from a centerline control position for a nearly flat strip having a width and first and second generally parallel edges as the generally flat strip moves along a particular feed line at a particular position, the error signal generating device including means for detecting the orthogonally projectable one-dimensional lateral position of the first edge of the moving strip at the determined position, means for detecting the orthogonally projectable one-dimensional lateral position of the second edge of the moving strip at the determined position , The system includes transducer means for detecting the lateral tilt angle of the strip at the determined position, means for generating an electrical value based on the detected tilt angle, means for generating edge signals indicative of the detected lateral positions of the edges of the web, and means responsive to the edge signals and the electrical value for providing an error signal responsive to the tendency to reduce the lateral offset of the web means from the central position for the web center.

Summary of the invention

The present invention relates to a device according to claim 1 and a method according to claim 13. The dependent claims contain advantageous embodiments of the invention.

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The device for detecting at least one orientation feature on a material web which extends in an intended material web direction in an intended material web direction comprises a sensor device which comprises a sensor element with at least one sensor line for detecting a sensor region on the material web. The device further comprises at least one light emitter in order to generate at least two points of light on the material web for determining a position of a material web level deviating from the intended material web level. The light transmitter is configured such that the at least two light points have a first distance on the material web extending in the intended material web plane. Furthermore, the light emitter is designed such that the at least two points of light have a second distance on the material web running in the deviating material web plane. The sensor device is designed such that the sensor element detects the first and the second distance for determining the position of the deviating material web plane. The position of the deviating material web level can thus be determined in a simple and cost-saving manner, and a simple and accurate detection of the at least one orientation feature on the material web can be made possible.

In various embodiments, the device may include one or more of the following features. The material web level that deviates from the intended material web level may be a material web level that has been rotated about an axis extending in the material web direction. The at least one light transmitter can be configured such that the at least two light spots in the sensor region lie on the material web. The sensor device may be configured such that the sensor element detects the at least two light spots on the material web for determining the position of the deviating material web plane. The light transmitter can furthermore be configured such that the at least two light spots on the material web are preferably on a line which runs perpendicular to the intended material web direction. configured such that the at least two points of light have a first distance on the material web extending in the intended material web plane. Furthermore, the light emitter configured in such a way that the at least two light spots have a second distance on the material web extending in the deviating material web plane. Sensor device designed in such a way The device may comprise means for evaluating the difference between the first and the second distance for determining the position of the deviating material web level. The light emitter can be designed in such a way that at least two light beams running parallel to one another are generated, which generate the at least two light spots on the material web. For this purpose, the device may comprise at least two light transmitters arranged parallel to one another. Alternatively, the device may comprise exactly one light transmitter and one beam splitter arrangement in order to generate the at least two light spots on the material web. The beam splitter assembly may comprise a semitransparent element and a reflective element. The Sensor device may be configured such that at least two sensor lines of the sensor element are at least partially read out in the material web direction in order to bring about an integration effect in the material web direction in the sensor region on the material web. The sensor element can be arranged in a plane extending obliquely to the intended material web level.

• Erfassen eines Sensorbereichs auf der Materialbahn durch eine Sensorvorrichtung, welche ein Sensorelement mit mindestens einer Sensorzeile umfasst,
• Erzeugen mindestens zweier Lichtpunkte auf der Materialbahn durch mindestens einen Lichtsender, und
• Bestimmen einer Lage einer von der vorgesehenen Materialbahnebene abweichenden Materialbahnebene mit Hilfe der mindestens zwei Lichtpunktes, wobei die mindestens zwei Lichtpunkte auf der in der vorgesehen Materialbahnebene verlaufenden Materialbahn einen ersten Abstand aufweisen und auf der in der abweichenden Materialbahnebene verlaufenden Materialbahn einen zweiten Abstand aufweisen, und wobei das Sensorelement den ersten und den zweiten Abstand erfasst zur Bestimmung der Lage der abweichenden Materialbahn.

The procedure

• Detecting a sensor region on the material web by a sensor device, which comprises a sensor element with at least one sensor line,
• Generating at least two points of light on the web by at least one light emitter, and
• Determining a position of a material web plane deviating from the intended material web level with the aid of the at least two light spot, wherein the at least two light spots have a first distance on the material web running in the provided material web plane and have a second distance on the material web running in the deviating web web plane, and wherein the sensor element detects the first and the second distance for determining the position of the deviating material web.

In another aspect, the method comprises

Embodiments may provide any, all, or none of the following advantages. By using at least one light emitter in order to produce at least one light spot on the material web, the position of the deviating material web plane can be determined in a simple and cost-saving manner. Thus, a simple and accurate detection of at least one orientation feature on the material web can be made possible.

Brief description of the drawings

FIG. 1A

ist eine Seitenansicht einer Vorrichtung zur Regulierung des seitlichen Versatzes einer Materialbahn;

FIG. 1B

ist eine Draufsicht von oben auf eine Vorrichtung zur Regulierung des seitlichen Versatzes einer Materialbahn nach FIG. 1A;

FIG. 2A

ist eine Darstellung von Materialbahnen, welche eine Linie als Orientierungsmerkmal aufweisen;

FIG. 2B

ist eine Darstellung von Materialbahnen, welche einen Kontrastunterschied als Orientierungsmerkmal aufweisen;

FIG. 3

ist eine schematische Schnittansicht einer Vorrichtung zur Detektion mindestens eines Orientierungsmerkmales auf einer Materialbahn, welche einen Lichtsender umfasst;

FIG. 4

ist eine dreidimensionale Ansicht einer Vorrichtung zur Regulierung des seitlichen Versatzes einer Materialbahn mit einer Vorrichtung zur Detektion mindestens eines Orientierungsmerkmales auf einer Materialbahn, welche einen Lichtsender umfasst;

FIG. 5

ist eine schematische Schnittansicht einer Vorrichtung zur Detektion mindestens eines Orientierungsmerkmales mit gerader Ausrichtung des Sensorelementes; und

FIG. 6

ist eine schematische Schnittansicht einer Vorrichtung zur Detektion mindestens eines Orientierungsmerkmales mit schräger Ausrichtung des Sensorelementes.

The present invention will be explained below with reference to preferred embodiments with reference to the accompanying drawings.

FIG. 1A

is a side view of a device for regulating the lateral offset of a material web;

FIG. 1B

is a top plan view of a device for regulating the lateral offset of a web after FIG. 1A ;

FIG. 2A

is an illustration of webs having a line as an orientation feature;

FIG. 2 B

is a representation of webs, which have a contrast difference as an orientation feature;

FIG. 3

is a schematic sectional view of an apparatus for detecting at least one orientation feature on a material web, which comprises a light emitter;

FIG. 4

is a three-dimensional view of a device for regulating the lateral offset of a material web with a device for detecting at least one orientation feature on a material web, which comprises a light emitter;

FIG. 5

is a schematic sectional view of an apparatus for detecting at least one orientation feature with straight alignment of the sensor element; and

FIG. 6

is a schematic sectional view of an apparatus for detecting at least one orientation feature with oblique orientation of the sensor element.

Detailed description of the drawings

In a device for regulating the lateral offset of a material web, as with reference to FIG. 1A and 1B explained, at least one orientation feature can be used to determine a lateral deviation of the web from a designated position. The at least one orientation feature may be, for example, a line or a pattern on the material web. The orientation feature can run in the material web direction and may be near the edge of the web or the edge itself. The sensor elements in this case may be optoelectronic sensors, such as color sensors or cameras.

In FIG. 2A are material webs which have a line as an orientation feature shown. In FIG. 2A a), a line 210 is scanned on a material web 200 in a sensor region 220. In FIG. 2A a) and c) are shown in each case continuous lines with uniform or disturbed background. In FIG. 2A b) and d) are each broken lines with a uniform or disturbed background to see. The device should be able to detect the orientation feature even with a disturbed background.

However, the at least one orientation feature can also be, for example, an edge of the material web or the like. In FIG. 2B a), a material web 200 is shown whose edge 211 is scanned in a sensor region 221. The orientation feature, the edge, is thus detectable as a contrast difference by the sensor device. In general, the sensor device can detect brightness and / or color differences of the orientation feature. The contrast can then be calculated accordingly. In FIG. 2 B Furthermore, orientation features are shown as contrast differences. In FIG. 2B a) and c) each continuous contrast edges are shown with uniform or disturbed background. In FIG. 2B b) and d) in each case interrupted contrast edges are seen with a uniform or disturbed background.

If nothing else is specified in the description that follows, the sensor element may have the following configurations. The sensor element may be, for example, a CCD sensor or CMOS sensor. The sensor element may be a line sensor, such as a CCD line sensor. However, the sensor element may also be a matrix sensor, such as a CCD matrix sensor or a CMOS matrix sensor.

The sensor element may be a black-and-white or gray-scale camera. Likewise, however, the sensor element can also be a color sensor which captures pixel by pixel with RGB evaluation. During each scan, the light is split into the primary colors red (R), green (G) and blue (B). Using an algorithm, the contrast differences can then be evaluated by a calculation unit, such as a processor, and a position of the orientation feature output. The contrast can also be calculated from the brightness differences as mentioned above.

FIG. 3 is a schematic sectional view of an apparatus for detecting at least one orientation feature 340 on a material web 300, which comprises a light emitter 330. The device further comprises a sensor device 370, which comprises a sensor element with at least one sensor line, for detecting a sensor region 308 on the material web. The material web 300 runs in an intended material web level in a designated material web direction (into or out of the drawing plane). If the material web is offset, the material web can run in a material web plane deviating from the intended material web level. In FIG. 3 the web is pivoted by the angle α about the pivot point 306. The material web 300 'then runs in a deviating material web plane, which is a material web plane rotated about an axis extending in the material web direction, a material web plane rotated about an axis passing through the pivot point 306. Accordingly, a material web pivoted in the opposite direction as the material web 300 "in FIG. 3 shown.

In determining the position of the orientation feature 340 on the web, the position of the orientation feature 340 within the sensor area 308 may be detected. If the material web is offset, for example as in FIG. 3 shown by the deviating material web 300 ', so the sensor area and the position of the orientation feature changes. This could lead to an error in the measurement of the position of the orientation feature 340.

However, after the determination of the position of the deviating material web level, this error can be compensated by appropriate calculations. For this purpose, the light emitter 330 generates a light beam 331 which generates two light spots 334, 335 on the material web 300. In this case, the light spots 334, 335 lie in the sensor region 308 on the material web 300 and can be detected by the sensor device 370. In FIG. 3 the two parallel light beams 332, 333 are aligned parallel and symmetrical to the main axis H of the objective of the sensor device 370. In order to determine the position of the deviating material web level 300 '(or 300 "correspondingly), the sensor device 370 can then detect the two light points 334', 335 'on the material web 300', whereby the two light points 334, 335 or 334 ', 335' lie. on the material web 300 or 300 'on a line which runs perpendicular to the intended material web direction, that is to say a line in the plane of the drawing in FIG FIG. 3 , On the material web 300 extending in the intended material web plane, the two light spots 334, 335 have a first distance 338. On the material web 300 'extending in the deviating material web plane, the two light spots 334', 335 'have a second distance 338'. To determine the position of the deviating material web level 300 ', the sensor element of the sensor device 370 can detect the first and the second distance. Furthermore, the difference between the first distance 338 and the second distance 338 'can then be evaluated to determine the position of the deviating material web level 300', for example by evaluation means which may be located in the sensor device or also outside thereof. These evaluation means can be used to generate a signal which indicates the position of the deviating material level.

To generate the two light spots 334, 335 and 334 ', 335' are in FIG. 3 generates two parallel light beams. The light emitter 330 emits the light beam 331, which is split by a beam splitter array 336, 337 into two parallel light beams 332 and 333. Here, the beam splitter assembly comprises the semitransparent element 336 and the reflective one Element 337. This beam split into two parallel light beams can be made very accurately and inexpensively, with a high manufacturing accuracy must be achieved only in the beam splitter assembly. The splitting of the light beam can also be generated by other means of beam splitting, such as a prism. Alternatively, to generate two light beams, the device may comprise two light emitters arranged parallel to one another.

It should be understood that several (more than in FIG. 3 shown two) points of light can be generated to determine the position of the deviating web level. It should be understood that any other detectable shape, such as a line of light, can be detected.

FIG. 4 FIG. 3 is a three-dimensional view of a device for regulating the lateral offset of a web of material 400 with a device 440 for detecting at least one orientation feature on the web of material 400. As already described with reference to FIG FIG. 1A and FIG. 1B explained, the web 400 undergoes a four times 90 ° deflection by the rollers 401, 402, 403 and 404. With the help of the driven by a drive device 460, such as a servomotor, pivotable positioning frame 405 can be a lateral material web correction cause. The material web is pivoted about the pivot point 406 by a certain angle. The material web is then fed via an outlet length of an outlet roller 404. In the area of the outlet length, the device 440 is located on the material web 400 for detecting at least one orientation feature. The at least one orientation feature in this case may be, for example, the material web edge 409 and / or a line located in the vicinity of the edge in the direction of the material direction A. In FIG. 4 the detection of the at least one orientation feature takes place in the transmitted light method with the aid of a light source 480, which is arranged on a side of the material web 400 opposite the sensor device 470. The device may also include more than one light source for different web surfaces. It should be understood that the device can also operate with reflected light or other suitable arrangements, but also no additional light source can be present.

The sensor device 470 detects the sensor region 408 on the material web 400 in order to detect the at least one orientation feature there. If the material web 400 is brought in the range of the outlet length by pivoting about a certain angle about the pivot point A from its intended material transport level in a different material web plane, the distance between the material web and the sensor element 470 is no longer constant. This deviating position of the material web can now be determined with the aid of the light transmitter 430. The light transmitter 430 generates two parallel beams with the aid of the beam splitter arrangement 436, 437, which generate two points of light in the sensor area 408 on the material web 400. The position of the deviating material web level can thus be determined in a simple and cost-saving manner, and a simple and accurate detection of the at least one orientation feature on the material web can be made possible.

The distance of the two light spots can be detected by the sensor device 470. A corresponding signal can then be given by the sensor device 470 to the control device 450. Taking into account this signal, the control device can determine the lateral offset of the material web 400 and control the drive device 460 accordingly.

The light emitter 330 may be a monochromatic light source, in particular a laser. However, other suitable light emitters may be used. If a laser is sent, it can be switched. In this case, the sensor device may detect the sensor area at a first time the light transmitter is switched off and there are no light spots. At a second time, the sensor device may detect the sensor area when the light transmitter is turned on and the light spots are present in the sensor area. It is then possible to form the difference between the data records acquired at the first and at the second time. As a result, the recognizability of the light spots on the material web can be improved.

FIG. 5 is a schematic sectional view of at least part of a device for detecting an orientation feature 540 on a material web 500. The sensor device 570 detects a sensor region 508 on the material web 500. A light source (not shown) can be used to illuminate the material web. The light rays incident on the sensor device 570 are focused by an optical element, a lens 572 disposed between the sensor element 571 and the material web 500, and hit the sensor element 571. This optical element can also represent the objective. In FIG. 5 the sensor element 571 is aligned straight, that is to say it is arranged in a plane extending parallel to the intended material web plane. It is also aligned vertically and symmetrically to the main axis of the lens. This in FIG. 5 The illustrated sensor element 571 comprises at least two sensor rows. It is therefore a matrix sensor element. Sensor element 571 may in particular be a CMOS matrix sensor.

At the in FIG. 5 shown sensor device 570 at least two sensor lines of the sensor element 571 in web direction A at least partially, but in particular completely, read out to effect in the sensor area 508 on the web 500 an integration effect in the web direction A. It can be read only a partial part of the sensor lines of the sensor element 571. A use of additional integration devices to widen the sensor area in web direction is thus not required. In addition, the number and range of the sensor lines, the partial part of the sensor lines to be read out, can be selected flexibly. In particular, can 1/10 or less of the sensor lines of the sensor element 571 are read out. If all sensor rows were read out for one scan, the sampling rate would be very low and the method would therefore be very slow. The sensor element can be read out, for example, with a frequency between 50 and 1000 Hz, in particular approximately 200 Hz. For example, a CMOS matrix sensor with a pixel count of 2500x1950 is mentioned here by way of example. If a possible readout frequency is 200 Hz and a scan, ie an image, consists of 30 lines, the result is a sampling rate of 6 scans per second. The size of an image with about 30 sensor lines is on the order of only about one-tenth of the 2500 or 1950 sensor lines available.

Also, the material web 500 can be offset by a displacement device in a deviating from the intended material web level material web level, as previously explained. In addition, the device may also include a light emitter to create at least one spot of light on the web of material to determine a location of the deviant web level, as previously discussed. The sensor lines of the sensor element 571 can then be read out in a sensor area 508 in the vicinity of the at least one light spot.

The imaging ratio of the sensor device 570 may be greater than 1: 2. The relationship between the image width b and the object distance g is to be understood as the image ratio. The image width here can be the distance between the sensor element 571 and the optical element 572. The object width g may be the distance between the material web 500 and the optical element 572. An imaging ratio greater than 1: 2 means that the object distance g is more than twice as large as the image width b. In particular, the imaging ratio may be in the range of 1: 4 to 1:10.

The device may further comprise a focusing element 573, which is arranged between the sensor element 571 and the material web 500. The Focusing element may include, for example, a piezoelectric element. With the aid of this, for example, the optical element 572 can be displaced in a direction parallel to the main axis of the objective, and thus effect a focusing by changing the image sharpness. The magnification is also changed.

If there is a deviation of the material web from the intended material web level, then the focusing element 573 can change the optical element, the lens 572, depending on the specific position of the deviating material web. In particular, at the in FIG. 5 a light emitter (not shown) may be used to determine the position of the deviating web level as shown with reference to FIG FIG. 3 and 4 explained. With the help of such a generated light spot or points of light on the web then autofocusing in dependence on the respective position of the deviating web level is possible.

FIG. 6 is a schematic sectional view of a device 670 for detecting at least one orientation feature 640 on a material web 600. In contrast to FIG. 5 Here, the sensor element 671 is arranged in a plane extending obliquely to the intended material web level, that is, it is arranged in a plane which forms an angle β not equal to zero to the intended material web level. Here, the sensor element 671 is not aligned in a plane perpendicular to the main axis of the objective. If the material web is moved through an offset device (as in FIG FIG. 1A and 1B shown) offset in a deviating from the intended material web level web surface, so a partial part of the sensor lines can be determined and read depending on the position of the deviating web level. In this way, autofocusing without the use of further focusing means is made possible. For determining the position of the deviating material web, a light transmitter can be used, as with reference to FIG FIG. 3 and 4 explained.

It should be understood that the various with respect to FIG. 3 to 6 described aspects can be combined in any meaningful way. For example, at the in FIG. 3 illustrated device with a light emitter and at least two sensor lines of the sensor element in the material web direction are at least partially read to cause an integration effect in the material web direction in the sensor region on the material web. Likewise, in the device of FIG. 3 the sensor element may be arranged in a plane extending obliquely to the intended material web level.

Claims (13)

1. A device for detecting at least one orientation feature (340) on a material web running in a predetermined material web plane (300) in a predetermined material web direction (A), comprising:

   a sensor device (370) comprising a sensor element having at least one sensor line for capturing a sensor range (308) on the material web,

   characterized in that
   the device comprises at least one light emitter (330) for generating at least two light points (334, 335; 334', 335') on the material web,
   wherein the light emitter (330) is configured so that the at least two light points (334, 335; 334', 335') have a first distance (338) on the material web running along the predetermined material web plane and a second distance (338') on the material web (300') running along the deviating material web plane,
   wherein the sensor device (370) is configured so that the sensor element captures the first and the second distance (338, 338') for determining a position of the material web plane (300') deviating from the predetermined material web plane (300).
2. The device according to claim 1, wherein the material web plane (300') deviating from the predetermined material web plane is a material web plane that is twisted about an axis running along the material web direction (A).
3. The device according to claim 1 or 2, wherein the at least one light emitter (330) is configured so that the at least two light points (334, 335; 334', 335') are located on the material web within the sensor range (308).
4. The device according to one of the claims 1 to 3, wherein the sensor device (370) is configured so that the sensor element captures the at least two light points (334, 335; 334', 335') on the material web for determining the position of the deviating material web plane (300').
5. The device according to one of the preceding claims, wherein the light emitter (330) is configured so that the at least two light points (334, 335; 334', 335') are located on the material web on a line which is perpendicular to the predetermined material web direction (A).
6. The device according to one of the preceding claims, wherein the device comprises means for analyzing the difference between the first and the second distance (338, 338') for determining the position of the deviating material web plane (300').
7. The device according to one of the preceding claims, wherein the light emitter (330) is configured so that at least two light beams (332, 333) running parallel to each other are generated that generate the at least two light points (334, 335; 334', 335') on the material web.
8. The device according to one of the preceding claims, wherein the device comprises at least two light emitters arranger parallel to each other.
9. The device according to one of the claims 1 to 7, wherein the device comprises exactly one light emitter (330) and a beam split arrangement (336, 337) for generating the at least two light points (334, 335; 334', 335') on the material web.
10. The device according to claim 9, wherein the beam split arrangement (336, 337) comprises a semitransparent element (336) and a reflecting element (337).
11. The device according to one of the preceding claims, wherein the sensor device (370) is configured so that at least two sensor lines of the sensor elements are read out in material web direction (A) at least partially to cause an integration effect towards the material web direction (A) in the sensor range (308) on the material web.
12. The device according to one of the preceding claims, wherein the sensor element is arranged in a plane inclined towards the predetermined material web plane.
13. A method for detecting at least one orientation feature (340) on a material web running in a predetermined material web plane (300) in a predetermined material web direction (A), which comprises:

    capturing a sensor range (308) on the material web by a sensor device (370) comprising a sensor element having at least one sensor line, characterized by

    generating at least two light points (334, 335; 334', 335') on the material web by at least one light emitter (330), and

    determining the position of a material web plane (300') deviating from the predetermined material web plane by means of the at least two light points (334, 335; 334', 335'),

    wherein the at least two light points (334, 335) have a first distance (338) on the material web (300) running along the predetermined material web plane and a second distance (338') on the material web (300') running along the deviating material web plane, and wherein the sensor element captures the first and the second distance (338, 338') for determining the position of the deviating material web plane (300').

Images