JP2003194513A - Device for detecting edge position of transmissive material, web edge controller, and printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for detecting edge position of transmissive material that detects the position of the edge 2 to be detected of an anisotropic transmissive material 3 (3'), is provided with at least one sensor 1 having a light source 4, two polarizing filters 6 and 7 respectively having transmission axes intersecting each other at 90°, and a light receiver 10, with the light source 4 and first polarizing filter 6 being positioned on one side of the edge 2 and the second polarizing filter 7 and light receiver 10 being positioned on the other side of the edge 2, and can be used without attaching work for detecting various kinds of materials having optical axes of different directionalities. <P>SOLUTION: In this device for detecting edge position of transmissive material, at least one sensor 1 is arranged and/or formed so that various angles may be obtained between the transmission axis of the first polarizing filter 6 and the optical axis of the anisotropic transmissive material 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting an edge position of an anisotropic and transparent material, the detection device including at least one sensor provided with a light source.
The light source and the first polarizing filter include two polarizing filters having transmission axes intersecting each other at an angle of 90 ° and a light receiver.
In which the second polarization filter and the light receiver are located on one side of the edge to be detected, and the second polarization filter and the light receiver are located on the other side.

The invention also relates to a web edge control device of the type provided with said device, a control device and a web edge adjusting device. Further, the present invention is
The present invention relates to a printing machine provided with such a web edge control device.

[0003]

BACKGROUND OF THE INVENTION To detect the edge position of a transparent material, from US Pat. No. 5,751,443, the light is directed to the transparent material as follows: It is known to detect the reflected light and thereby direct it to determine the edge position. In sensors operating according to this type, contamination of the material results in a weakening of the reflection properties, which leads to inaccurate or impossible detection of the edge position. The problem is that printing machines provided with a permeable web for transporting printed substrates, especially electrophotographic printing machines,
Occurs especially in the case of circulating webs carrying substances. Such web edges need to be detected to adjust the position of the web.

In order to solve this problem, German Patent Application No. 19906154 proposes a device of the type mentioned at the beginning of the description. According to its functional principle, light does not pass through a polarizing filter having transmission axes that intersect each other at an angle of 90 °. This is because only polarized light that is blocked by the second polarizing filter passes through the first polarizing filter. The introduction of anisotropic material with a special optical axis between the polarizing filters gives rise to rays or partial rays, the polarization direction of which is rotated by an angle of 90 °. Since this light passes through the second polarization filter,
Material edges are clearly imaged on the receiver. This imaging is less sensitive to smear than reflection-based imaging. The problem with this arrangement is that when light is incident on the transparent material along the optical axis of the material, no rays or partial rays of polarized polarization are produced. That is, the light must be angled with respect to the optical axis to ensure good detection and formation of a light portion that is rotated in the polarization direction. The optical axes of anisotropic and transparent materials inevitably have different directions depending on the manufacturing process and mechanical load even if the materials have the same scientific composition. This means that such a device must be aligned with respect to each optical axis, in which case a beam of light with a polarization direction of good detectable intensity is formed. For this reason, it is necessary to newly perform this alignment depending on the material strength to be detected. A web for delivering material requires alignment of the sensor with respect to the optical axis of the new web each time the web is replaced with a new web. Such problems can already occur with increasing or decreasing mechanical load on the web.

[0005]

SUMMARY OF THE INVENTION The object of the invention is therefore to improve the device for detecting the edge position of an anisotropically transparent material of the type mentioned at the outset, in order to achieve different orientations. It is to provide what can be used without mounting work for detecting a material having an optical axis.

[0006]

According to the device of the present invention for solving this problem, there is a difference between the transmission axis of the first polarizing filter and the optical axis of the anisotropic and transparent material. At least one sensor is arranged and / or formed in such a way that the angle is obtained.

[0007]

The arrangement according to the invention provides a device capable of detecting the edges of anisotropic, transparent materials, in which case a simple swiveling movement or a change in the angular position of the polarization is obtained. Another position change by means of the device results in a device position which is necessary for the detection of the material and which allows the alignment of each material with respect to the optical axis. In this way, an accurate detection of material edges that is less sensitive to dirt is possible, which makes it possible, in particular, to convey and circulate the material, for example the anisotropic, transparent web of electrophotographic printing machines. , The web edge control solves the above-mentioned problems.

The problem of different optical axes arises, inter alia, from the fact that the optical axes of the webs have different orientations with respect to production and the difficulty of detecting and adjusting the position of such webs. . Web edge control is provided by the apparatus of the present invention, where the optical path is aligned or alignable with the edge of the anisotropic, transparent web to be detected as follows: However, it can be aligned or aligned in such a way that it can be adjusted to any course of the optical axis due to changes in the optical axis of the web, so that no mounting work is required. For this purpose, one sensor may be arranged pivotably, or several sensors may be arranged at different angular positions and an appropriate sensor may be selected, or the optical path of the sensor may be the optical path and thus the polarization. However, it is changeable so that it can occupy various different angular positions with respect to the material to be detected and thus its optical axis.

The device of the invention reduces maintenance costs, personnel for installation and machine downtime during web changes, especially in the case of printing presses. Even in the case of changes in the mechanical load of the web and the resulting changes in the position of the optical axis, the device according to the invention can be readjusted with little effort with regard to the alignment of the optical paths. Another area of use of the present invention is to detect the edges of individual pieces of material. This is because, in this case as well, it is necessary to take into account different courses of the optical axis.

By means of the device according to the invention, in a simple manner, the polarization occupies an angular position with respect to the material, at which angular polarization of the light emitted by the first polarizing filter by the material to be detected. Is achieved to a sufficient extent for the detection of edges, which is advantageously between the transmission axis of the first polarizing filter and the optical axis of the anisotropic, transmissive web. Is selected so that the receiver can be imaged with the best possible edges. Optimum conditions are achieved at angles of 45 °, but angles in the angular range between 25 ° and 65 ° are sufficient to image the edges.

There are various embodiments for moving the sensor to various positions to achieve the aforementioned angles,
Alternatively, there are different embodiments of providing different angular positions of polarization with respect to the material to be detected. According to an embodiment of the invention, the angle between the transmission axis and the optical axis is precisely adjusted or the angular position of the sensor is chosen in the angular range of 25 ° to 65 °. Often two predetermined angular positions are provided, and it is sufficient to select for each material the angular position at which the edges are well imaged. According to another embodiment, a predetermined number of angular positions are provided so that for each material an angular position is selected in which the edges are well imaged. Such selection of the angular position or precise adjustment of the angle advantageously allows the alignment of the optical axis of the material to be detected to be restricted to a specific angular region, but to be provided with different optical axes. The best possible angle is chosen if it is possible to occupy all feasible directions or for good imaging of the edges, for example when it is necessary to detect material with reduced permeability due to dirt. .

According to an embodiment of the present invention, the sensor can be manually pivoted to various positions and locked in that position. This can be achieved by any simple mechanism. According to yet another embodiment, a drive is provided, which drives the sensor to an optimal position of feasible positions with different angular positions. This is advantageous when the sensor is located at a machine location that is difficult to approach. In yet another embodiment, a controller is provided that is connected to the photoreceiver and selects the angular position for imaging the edge on the photoreceiver. This control device can, for example, direct the movement of the sensor to the optimum position. For example, the controller serves to connect multiple locations and select the most contrasting edge imaging. Moreover, the sensor can find the optimum optical path from the angular positions of the optical paths incorporated in any form, or can adjust the optical path in an appropriate form. Such a device is extremely comfortable since it does not require any operation. Such a control device is very advantageous when the material to be detected is an individually conveyed piece of material with an optical axis of different orientations. This is because this controller automatically guarantees good edge detection.

According to yet another control device embodiment,
A controller adjusts the intensity of the light source and / or the required sensitivity of the receiver. Advantageously, the control device reacts automatically to changing conditions, which guarantees satisfactory edge imaging. Such a situation change
Present when fouling occurs or one seeks to detect materials with varying strengths of permeability.

The controller can adjust the adjustment value based on an appropriate algorithm of the program, or the controller can store the adjustment value for a given position. In this way an optimum adjustment is guaranteed.

The photoreceiver can be formed from a plurality of receiving elements, for example as an array of receiving elements, which is a CCD array. Alternatively, the light receiver can be formed as a flat light receiver. With such an arrangement, digital position values can be obtained for continued processing in the electronic control unit. In this case, the flat light receiver has the advantage that the inclination of the edge can be detected using a single light receiver.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the illustrated examples.

FIG. 1 shows an exemplary embodiment of the web edge control device 16 of the invention, which comprises the device of the invention in the form of a swivelable sensor 1. The sensor 1 is used to detect an edge 2 of an anisotropic, transparent material 3, for example a transparent web 3 '.

The sensor 1 comprises a light source 4 and two polarizing filters 6, 7 whose transmission axes 8, 9 intersect with each other at an angle of 90 °. Furthermore, a light receiver 10, which is embodied as a CCD array or an array of receiving elements, is arranged. Light source 4
And the first polarizing filter 6 is located on one side of the anisotropic and transparent material 3 or 3'to be detected with respect to the edge 2, and the second polarizing filter 7 and the receiver 10 are made of material. Located on the other side of 3, 3 '.

According to the invention, it is proposed that the light source 4, the polarization filters 6, 7 and the light receiver 10 be arranged such that they can be arranged as follows, that is to say that the sensor 1 has different positions 11, 11 '. , 11 ″, ..., and these different positions 11, 11 ′, 11 ″,
It has been proposed that the polarized light 5 be formed so that it can occupy different angular positions 12, 12 ′, 12 ″, ... With respect to the material 3, 3 ′ to be detected. 11, 11 ', 11'',
... are different angular positions 12, 12 ', 12'', ...
Together, it helps to find the angle 32 of the transmission axis 8 of the first polarization filter 6 with respect to the optical axis 14 of the material 3, 3 ', which allows good detection of the edge 2 (see FIG. 2). For this purpose, the sensor 1 is formed in such a way that the light source 4, the polarization filters 6, 7 and the light receiver 10 are located on a common support 30, which can be swiveled around a swivel axis 19. is there. This turning degree is at position 11,
In order to be able to select 11 ', 11'', ...
The sensor 1 moves from the position 11 shown to another position 11 ', 1
1 '', ..., the polarized light 5 guarantees the optical axis 14 of the material 3, 3'and the optical component in this position 11, 11 ', 11'',. , The polarization direction 22 of the light component is rotatory and has sufficient intensity to be detected by the light receiver 10. For this purpose sensor 1
Consequently, the polarized light 5 has the angular position 12 'shown in this embodiment.
Or occupy 12 ″. In this case, both angular positions 12 ′, 12 ″ shown can be set, or an arbitrary angular position 12 can be set as a realizable position within a swivel area that is mechanically realizable.

Such a sensor 1 can be manually swiveled and can be formed so that it can be locked at various positions 11, 11 ', 11 ", .... In the illustrated embodiment, a drive device 13 is provided, which drive device 13
Can be moved to different positions 11, 11 ', 11'', .... For this purpose, a control device 15 connected to the light receiver 10 by a connecting line 20 serves, which control device 15 is located at one position 11, 11 ′, 1 of the sensor 1.
1 ″, ... and selecting the edge 2 using the drive unit 13.
.. are instructed by the sensor to occupy positions 11, 11 ', 11 ", ... When such a clear image formation is obtained, the control device 15 determines, based on the value obtained by the light receiver 10, a web edge adjustment which is connected to the control device 15 by the connecting line 20 in the same manner as the driving device 13. Device 1
8 is used to instruct the adjustment movement 17 for reaching the target position of the edge 2. The drive 13, the control device 15 and the web edge adjusting device 18 are shown in principle.
These elements can be of any design, and the drive and control can also set the vertical axis mentioned above.

A functional principle diagram of the sensor 1 is shown in FIG. The light source 4 emits unpolarized light 21, in this case polarized light 5.
Only the first polarizing filter 6 is transmitted, and the polarized light 5 has the polarization direction 22 of the transmission axis 8. In this case, in the illustrated embodiment, the transmission axis 8 is y- with respect to the coordinate system x, y, z.
It is located at an angle of + 45 ° with respect to the y axis in the z plane. As long as this polarized light 5 does not reach the anisotropic, transparent material 3, 3 ′, the polarized light 5 maintains its polarization direction 22 and then at an angle of 90 ° to the transmission axis 8 of the first polarizing filter 6. It is rotated, that is, -4 with respect to the y axis in the yz plane.
It reaches the second polarizing filter 7 with its transmission axis 9 located at an angle of 5 °. Therefore, the polarized light 5 of the light rays extending above the transparent material 3 cannot pass through the second polarizing filter 7. Anisotropic and transparent material 3
The ray of polarized light 5 that reaches is different from this. The course of the optical axis 14 of the material 3 leads to an optical rotation in the polarization direction 22 with respect to the light component of the polarized light 5, whereby this light component of the polarized light 5 is polarized in the direction of the transmission axis 9 of the second polarization filter 7. And therefore the second polarization filter 7
Can pass through. Polarized light 5 passing through the second polarizing filter 7
Are detected by the light receiver 10. A plane 23 illuminated by this polarized light 5 results. In this case, edge 2 of material 3 is imaged as edge 24. In this way, the positions of the transparent material 3 and the edge 2 are accurately detected. The remaining surface of the light receiver 10 remains dark. This is because the polarized light 5 that has been rotated in the polarization direction 22 without passing through the transparent material 3 is blocked by the second polarization filter 7.

The present invention serves to adjust the transmission axis 8 of the first polarizing filter 6 with respect to the optical axis 14, by means of which adjustment is clearly imaged on the basis of the selected angular position 12. The polarized light 5 reaching the photodetector 10 has such an intensity that the edge 2 can be detected as the edge 24.
Is guaranteed to have. Angular position 12
Is obtained by a swivel carried out in the direction of the arrow denoting the angular position 12 about a swivel axis 19 indicated by a dashed line according to FIG. Due to the swiveling in the yz plane, the angular position 12 is changed between the polarized light 5 and the material 3,3 'to be detected, and thus between the transmission axis 8 and the optical axis 14. The change in the angular position 25 of the optical axis 14 of the materials 3 and 3'is also y-
As it is obtained in the z-plane (this change is indicated by the dash-dotted line arrow indicating the angular position 25), in this plane a corresponding arrangement of the course of the transmission axis 8 with respect to the optical axis 14 is obtained, Sufficiently guarantees the rotation of the polarization direction 22.

3a-3c, with respect to the efficiency 26 of the sensor 1, the angular positions 25, 25 ', 25'', of the optical axis 14 are shown.
The effect of the different angular positions 12, 12 ', 12''of the polarized light 5 on the materials 3, 3'is shown.

In FIG. 3a different angular positions 25 of the optical axis 14 of the material 3 are shown, the angular position 25 'being-.
At an angle of 35 °, the angular position 25 ″ is located at an angle of + 35 °. The region between these two angular positions is the general variation region of the angular position 25 of the optical axis 14 in the production of the transparent material 3 '.

In FIG. 3b, the swiveling movement of the sensor 1 is shown, by means of which swiveling movement the transparent material 3,
The sensor 1 can be adjusted in such a way that the edge 1 of the material 3, 3'can be detected by the sensor 1 despite the different angular positions 25 of the optical axis 14 of the 3 '. For this purpose, in the embodiment of FIG. 3b, the sensor 1 occupies an angular position 12 'of -17 ° or an angular position 1 of + 17 °.
It is proposed to occupy 2 ″. That is, the sensor 1 is not located at the position 11 at an angle of 0 ° indicated by the dashed line, but at the position 11 'or 11''with respect to the material 3, or 3'to be detected. Here, the rotation of the sensor 1 depends on the material 3, which the polarized light 5 seeks to detect.
Different angular positions 12, 12 ', 1 with respect to 3'
It is just one example for allowing 2 ″, ... Different angular positions 12, 12 ', 1
Other configurations are also conceivable, such as attaching 2 ″, ... Polarized light 5.

The effect of the angular position 12 or 12 'on the efficiency 26 of the sensor 1 is shown in FIG. 3c. In this case the curve 27 is shown for the efficiency 26 of the sensor 1 located at the position 11 shown in phantom in FIG. In this case, the polarized light 5 occupies an angular position of 0 ° with respect to the material 3 at the point 31, here the optical axis 14
With the position of the transmission axis 8 offset by 45 ° with respect to (see FIG. 2), a maximum efficiency of 100% that can be achieved 26
Is obtained. However, such positioning has the disadvantage that by the angle 25 of the optical axis 14 becoming -35 ° or + 35 °, the efficiency drops to zero and thus the sensor 1 fails.

As shown in FIG. 3b, the sensor 1
An embodiment has been proposed in which is movable to two positions 11 ', 11''. Its action is curve 2 in FIG. 3c.
8, 29. Here one curve 28 is
Shows the efficiency of the first sensor, with polarization 5 at angular position 1
2 ′, that is to say at an angle of −17 ° with respect to the vertical direction, on the surface of the material 3. The other curve 29 is the curve 2
8 extends in the positive region with respect to 8 and shows the efficiency 29 of the sensor 1. Here, polarization 5 is at angular position 1
2 ″, that is to say on the surface of the material 3 at an angle of + 17 ° with respect to the vertical direction. In this case both angular positions 1
2 ', 12''are set such that optimum efficiency 26 is guaranteed at these angular positions 12', 12 '', i.e. at angles of -17 ° or + 17 °. These points 3
The maximum efficiency 26 of 100% is obtained at 1,31 ', which is obtained at the angular positions 12', 12 '' of the polarization 5 and by the transmission axis 8 being at an angle of 45 ° with respect to the optical axis 14. (See FIG. 2). This is achieved by occupying two feasible angular positions 12 ', 12 ", such that the material is transparent such that the optical axis 14 moves in an angular region 25 well beyond the angles of + 40 ° to -40 °. It is understood that 3,3 'can be detected and in this case the efficiency 26 is still at least 80% at the angular position of 35 °. Therefore ± 45 ° with respect to the angular position of 0 °
The material can still be detected well up to the angular position 25 of the optical axis 14 at an angle of 1, which is not possible at the position 12.

FIG. 4 shows an example of the angular position 25 with respect to the product of the optical axis 14 of the anisotropic, transparent material 3 '. In the production of such webs 3 ', a wide web is often produced for cost reasons and a plurality of webs 3'are cut from this wide web. A corresponding course of the angular position 25 of the optical axis 14 with respect to production corresponds to the course shown. As a result, the course of the optical axis 14 becomes 0
It is possible for the angle to vary between ° and up to ± 45 °, in which case the individual webs 3'may also have some angular difference in width. That is, the sensor 1 has to be adjusted to the angular position 25 of the optical axis 14 in the region of the web 3'where the edge 2 is to be detected. Such an adjustment can be accomplished by a swivel movement of the sensor 1 of the invention or an angular position 25 of the polarization 5.
25 ', 25'', etc. can be carried out without problems, such a web 3 can be detected accurately and the position of the web 3'can be adjusted by the adjusting movement 17 on the basis of the detection. This is especially important for electrophotographic printing machines. Because a web 3'of the type shown in FIG. 4 is used, and in the case of replacement of the web 3 ', the web edge control device 16 operates the machine again with a minimum of downtime, without loss of time. It must be possible to adjust to the new course of the optical axis 14. Furthermore, the invention allows the user of the printing press to replace the web 3 '. This is because no complicated work is required to adjust the sensor 1.

Of course, the illustrated embodiment is merely exemplary. The drawing shows how the sensor 1 and the web edge control device 16 can be realized and clarifies the functional principle of the invention. The different positions of the sensor 1 are not only obtained by a swivel movement about a swivel axis 19, but also the sensor 1 is moved to different positions 11, 11 ', 11'', ... (even in a larger adjustment area). It can also be obtained using another mechanical device for positioning. Furthermore, the arbitrary position 1 of the sensor 1
It is also possible to set 1 or to set a certain number of positions 11, 11 ', 11''. Each embodiment is directed to how it is desirable to use the sensor 1 correctly.

Instead of mechanical positioning, of course, an arrangement of several sensors 1 may be provided, as already mentioned, or the angular positions 12, 12 ', 12'',
, May be identified by selecting one sensor from a plurality of sensors positioned at different angular positions 12, 12 ′, 12 ″. It is also possible to form the sensor 1 with an optical path of different angular positions 12, 12 ', 12 ", ..., Here one of the different angular positions is selected for detecting the edge 2 of the material 3, 3'. To be done. An adjustable light path may be provided.

[Brief description of drawings]

1 shows a perspective view of an exemplary embodiment of a web edge control device according to the invention with the device according to the invention formed as a swivelable sensor, FIG.

FIG. 2 is a functional principle diagram of the sensor of FIG.

3a, 3b and 3c show the effect of different angular positions of polarization on materials with different angular positions of the optical axis, on the efficiency of the sensor.

FIG. 4 shows an example of various angular positions of the optical axis of the web with respect to the product.

[Explanation of symbols]

1 sensor, 2 edges, 3, 3'material, 4
Light source, 5 polarized light, 6, 7 polarized light filter, 8, 9
Transmission axis, 10 light receivers, 11, 11 ', 11'',
... position, 12, 12 ', 12'', ... angular position,
13 drive device, 14 optical axis, 15 control device,
16 web edge control device, 17 adjustment movement,
18 web edge adjuster, 19 swivel axis, 2
0 connection line, 21 non-polarization, 22 polarization direction,
23 planes, 24 edges, 25, 25 ', 25'',
... Angular position, 26, 27, 28, 29 Efficiency, 30
Support, 31, 31 'points, 32 angles

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Rolf Spilz             Federal Republic of Germany Getdorf Zeiz             Dichweg 5 (72) Inventor Patrick Metsler             Federal Republic of Germany Getdorf Linden             Hoff 65 (72) Inventor Stephan Teden             Kiel Flensburg, Federal Republic of Germany             Gerstraße 7 F term (reference) 2F065 AA12 AA31 BB13 BB22 CC01                       DD09 FF04 FF49 HH14 JJ03                       JJ05 JJ26 LL21 MM25                 3F048 AA01 AB05 AC02 BA20 BA22                       BB09 DC13

Claims (16)

[Claims] 1. A device for detecting the position of an edge (2) of an anisotropic, transparent material (3, 3 '), said detection device comprising at least one light source (4). The transmission axis (8, 8) intersecting the sensor (1) at an angle of 90 °.
Two polarizing filters (6, 7) having 9) and a light receiver (10), said edge (2) to be detected by said light source (4) and said first polarizing filter (6). ) On one side and the second polarizing filter (7) and the light receiver (10) on the other side, the first polarizing filter (6) ) Transmission axis (8) and the optical axis (14) of the anisotropic and transparent material (3) at least one said sensor (1). A device for detecting the edge position of a transparent material, characterized in that it is arranged and / or formed. 2. The material to be detected (3,3 ′)
The angle (32) is selected such that the rotation of the light (5) emitted from the first polarization filter (6) is sufficient to detect the edge (2). 1. The device according to 1. 3. Device according to claim 2, wherein the angle (32) is chosen such that the imaging of the edge (2) is as good as possible on the light receiver (10). 4. An angular range in which the transmission axis (8) of the first polarizing filter (6) with respect to the optical axis (14) of the transparent material (3, 3 ') is between 25 ° and 65 °. The device of claim 3, wherein the device comprises: 5. Two predetermined angular positions (12, 1)
2 ″) is provided and for each material (3, 3 ′) the edge (2) is well imaged at the angular position (1
2'or 12 '') are selected,
Device according to any one of claims 1 to 4. 6. A number of predetermined angular positions (12,1)
2 ″) is provided and for each material (3, 3 ′) the edge (2) is well imaged at the angular position (1
2, 12 ') are selected.
The described device. 7. The sensor (1) is placed at the optimum position (11, 1).
7. Device according to claim 5 or 6, characterized in that it is provided with a drive (13) for moving it to 1 ', 11''. 8. Connected to the light receiver (10),
8. A light receiving device (10) is provided with a control device (15) for selecting the angular position (12 ', 12'') for imaging the edge (2). The device according to item 1. 9. Device according to claim 1, wherein a control device (15) for adjusting the intensity of the light source (4) is provided. 10. Device according to claim 1, further comprising a control device (15) for adjusting the required sensitivity of the light receiver (10). 11. The device according to claim 5, wherein the control device (15) stores an adjustment value for a predetermined angular position (12 ′, 12 ″). 12. Device according to claim 1, wherein the light receiver (10) is formed from a plurality of receiving elements. 13. The device as claimed in claim 1, wherein the light receiver (10) is embodied as a flat receiver. 14. A device according to claim 1, wherein the light receiver (10) is formed from an array of receiving elements. 15. A web edge control device (16) according to any one of claims 1 to 14, wherein the detection device, the control device (15) and the web edge adjustment device (18).
In the type provided with and, for at least one edge (2) of the anisotropic, transparent web (3 ') to be detected, at least one sensor is provided with an optical axis of the web (3'). Based on the change of (14), the optical axis (1
4) A web edge control device, characterized in that it is shaped and / or arranged in such a way that it can take into account any possible course of 4). 16. A printing machine provided with an anisotropic, transparent web (3 ') for transporting a printed circuit board, wherein the web edge control device (16) according to claim 15 is provided. A printing machine characterized by the above.