DE2658659A1 - Installation identifying register marks on colour printing machines - locates marks on reading tracks and checks by fixed optical sensor system - Google Patents

Abstract

The installation identifies register marks positioned on a running track along two reading tracks next to each other and checked by two rigidly fixed optical sensor systems also lying next to each other. The tracks are investigated for their relative position to each other. At least one of the register marks is located in front of a set sequence of further check marks. Gaps are picked up sequentially by the sensor systems before the register marks. The signals emitted by the sensor systems are then examined for the pre-set sequence of check marks and gaps.

Description

Method and device for identifying remnants

The invention relates to a method and a device to identify two on a running track along two broom tracks register marks arranged next to one another, which are characterized by two Fixed optical systems detected and examined for their relative position to each other will. Only one optical head is used for the pickling broom marks contains the two associated optical scanning systems.

Register marks are used, for example, to control multi-color printing machines used, where it is important that the individual Weil-color images are exact This exact alignment is brought about by that with the first printed partial color image first register marks and with the following Partial color images are also printed with further register marks, the to be compared Register marks come to lie next to each other along two reading tracks. Means an optical scanning device, the positions the one in the direction of transport of the paper, seen register marks printed first with those printed subsequently Register marks compared. If there is a position shift of the adjacent and register marks to be compared, a suitable adjusting device is used the phase position of the individual printing cylinders is adjusted so that the register marks and thus also the individual partial color images relatively in the desired tolerance range be aligned to each other.

An electro-optical suitable for the purposes of the present invention Scanning device is described in German patent application P 26 30 209.0. In the German patent application P 26 36 906.2 a circuit arrangement is for Generation of a switching signal when passing through a contrast jump described, which is also applicable in connection with the present invention.

Because the individual register marks are applied between printed areas and register marks as well as printed areas pass through the field of view of the button, However, if this recognizes contrast differences in both cases, the following must Signal processing logic is informed of the area in which register marks are expected will.

In known processes, this is done regularly via a so-called phase switch, which is synchronously and phase-locked with the paper transport and for the given Time allows the read command for a certain distance.

There is also a method known (DT-AS 1 499 007) with which the identification of the register marks applied for tax purposes even without additional external means, such as a phase switch, is possible. To do this, a optical scanning device used with five adjacent reading tracks. The mark has a width of about three reading tracks and is arranged so that it the first reading track is not touched, the second, third and fourth Reading track runs through and finally does not touch the fifth reading track either. This brand is then recognized if after the previous print image until the arrival of the Mark a minimum distance is covered in reading lanes 2, 3 and 4, and if the mark itself has a minimum width, which of the buttons of the second, third and fourth reading track is detected, and if finally at this point in time there is no print mark in the first and fifth reading track.

However, this known method has the disadvantage that a scanning device with five reading systems is required, which are mutually exclusive for large scanning distances can influence. Large sensing distances, i.e. a large space between the The paper web to be scanned and the optical scanning device are useful in order to minimize the contamination of the optical system by paint splashes to keep. Large scanning distances can even be absolutely necessary, namely if Machine units are passed between the paper web and the scanning device have to. Furthermore, a register mark can relatively often in the known method be fooled by the print image No.

The aim of the invention is thus to provide a method and a To create device of the type mentioned, in which only two scanning tracks are required, which are usually necessary anyway to compare the register marks the use of known optical scanning devices being possible target. Due to the use of only two scanning tracks, it is possible to create a large one Observe scanning distance without the optical scanning devices mutually disturbing influence. Furthermore, the invention is intended to reduce the relative frequency the pretense of a register mark by the Print image so strong can be reduced so that practically no more disturbances occur. Despite this according to the invention intended simplification is to be applied to the known device mentioned at the beginning required phase softness can be dispensed with, which at the time of reading the print-free Space between two print images activated the evaluation, thereby creating an offset of the two register marks in the two reading tracks.

To solve the problem, the invention provides that at least'einer of the two register marks a predetermined sequence of further test marks and bridges is connected upstream, which in front of the register marks one after the other by the optical scanning systems are detected, and that the signals emitted by the optical scanning systems be examined for the presence of the predetermined sequence of test marks and gaps. Preferably, further test marks and bridges are connected upstream of the two register marks. The length of the test marks and stoops can be set with fixed setpoints be compared, or the length of the check marks and stooping will be based on the presence examined a predetermined ratio. Because of this approach, in the evaluation for the predetermined brand configuration to generate a Identification signal exploited, while all others are present in the print image Variants are not taken into account. The likelihood of pretending a register mark can be determined by suitable selection of a predetermined sequence of test marks and pieces are kept very low. Provided there is a permissible tolerance for each brand of + 5% is accepted, the hit probability is for the individual Brand, assuming that statistically all possible brand lengths are offered at 1: 10. Since this hit probability also applies to the other length measurements the gaps and test marks apply, multiply according to the law of multiplication the calculus of probability the independent occurring from each other Events, so that, for example, with five length measurements, a hit probability for a false identification of a register mark of 1: 100 000 is present. By Appropriate distribution of the check marks on the two reading tracks can reduce this probability can be further reduced.

Even if only the aspect ratio of the test marks and pieces are examined with respect to one another, the probability of an incorrect identification is still 1: 20,000 with a total of five length measurements. Even this value exceeds the results of known processes are still orders of magnitude.

It is preferably provided that the front and rear edges of the test marks in one broom lane do not coincide with those in the other broom lane.

For practical purposes it is fully sufficient if one of the register marks two test marks and two pieces are connected upstream, while the other register mark only one test mark and one piece is connected upstream. It extends that of the other The test mark assigned to the register mark is expediently positioned over two of the one register mark assigned test marks.

While the two register marks one after the other together with them assigned partial color images are printed, all test marks, even if they are in different reading lanes, together with one of the register marks can be printed in order to achieve clear allocation relationships.

The preferred device for carrying out the method according to the invention with two reading tracks detecting optical heads, which one of the detected brightness emit a corresponding electrical signal, is characterized by that the optical heads are connected to a control unit in which the predetermined test mark-gap sequence is saved, and which is stored at the beginning of each test mark or

Gap triggers a counter assigned to this, to it at the end of the stop the relevant test mark or gap again and make a comparison with the Trigger target length.

Preferably only one of the ones immediately in front of the register marks is issued a counter is assigned to lying gaps.

According to a simple embodiment, the comparison can thereby be brought about that a comparator acted upon by the control unit is connected to each counter is. The control unit and all comparators are expediently connected to an AND gate applied, at the output of which the identification signal is picked up.

According to a first embodiment, the frequency is that of the counters supplied pulses proportional to the web speed. This can reduce the length of the individual test marks and gaps can be measured exactly.

Another embodiment is characterized in that the frequency of the pulses fed to the counters is constant and the count of the first Counter is used as a reference value for the subsequent length measurements. In this embodiment, there is only the length ratio of the individual test marks and gaps can be determined. However, this has the advantage of simpler pulse generation opposite to.

The invention is illustrated below, for example, with reference to the drawing described; 1 shows a schematic perspective plan view a printed paper web with a device arranged above it according to of the invention, FIG. 2 is a plan view of that arranged in the paper web of FIG Test marks and gaps, including the voltage curve over time at the output different stages of the device according to the invention shown in the form of diagrams FIG. 3 is a schematic block diagram of a preferred embodiment the device according to the invention.

According to Fig. 1, a printed with partial color images 40, 41 moves Paper web 39 in the direction of arrow f under two optical scanning systems 19, 20 through. The scanning systems 19, 20 contain a common light source 44, which illuminates two reading tracks 25, 26 via lenses 45, 46, which are parallel to the Web travel direction f extend at a distance from one another along the paper web 39.

The optical scanning systems 19, 20 have lenses 47, 48, by means of which the illuminated by the light source 44 area of the reading tracks 25, 26 to a Photoelectric receiving arrangement is imaged. The photoelectric receiving arrangement is preferably designed according to German patent application P 26 36 906.2.

Between the two each at least two Geilfarben pictures existing print images 40, and 41 is a space in which transversely Over the brush marks 25 and 26 next to each other register marks 11 and 12 as well as the test marks 14, 16 and 17 are printed. The register mark 11 is together with the first Partial color image printed so that it is exactly aligned with this. The registration mark 12 is printed along with the following partial color image and is therefore related precisely aligned to this. Any misalignment of the two partial color images so beats itself in a corresponding misalignment of the registration marks 11 and 12 down. This detected by the two optical reading systems 19 and 20 Misalignment is a suitable adjusting device for the phase position of the printing cylinder, which prints the second partial color image, causing misalignment is eliminated by appropriately readjusting this pressure cylinder.

According to the register mark 11 are test marks 14, 16 and press 13, 15 upstream, while in front of the register mark 12 a test mark 17 and a Gap 18 are arranged. The test marks 14, 16, 17 are expediently printed together with the register mark 11 when printing the first partial color image.

When transporting the paper web f in the direction of arrow f, are the individual marks are scanned one after the other via the two scanning systems 19, 20. The electrical output signals as a function of time are in the first both diagrams 19 and 20 in FIG. These signals become two pulse shaping stages 42, 43, which turn the signals from the optical heads 19, 20 into pulse trains, If they are shown in diagrams 42 and 43 in Fig. 2 It should be noted that that according to FIG. 2, the leading edge of the test mark 17 seen in time between the Leading edge 22 and trailing edge 23 of the test mark 16 falls, while the trailing edge 24 of the test mark 17 between the front or

Rear edges 22, 23 of the test mark 14 is arranged.

It should be noted that those shown in diagrams 19 and 20, respectively Output signals are reproduced in a highly idealized manner.

In Fig. 3 top left, the paper web 39 is again schematically in a A view similar to FIG. 1 is shown in simplified form. The ones from the pulse shaper stages 42, 43 exiting signals are fed to a control unit 27 in which, inter alia. the predetermined sequence of test marks and gaps is stored.

The length measurement takes place in that the repeat length of a print image or the printing cylinder volume is divided into sections, which by more than are an order of magnitude smaller than the smallest test mark or gap to be measured. For this purpose, a perforated or raster disk is used with a further optical button 49 50 scanned, the peripheral speed proportional to the speed of the Paper web 39 is so that the paper web 39 from pulse to pulse always a predetermined covers a constant distance. According to Fig. 3, the perforated or raster disk 50 is in the illustrated manner with a pair of rollers engaged with the paper web 39 51 coupled. The pulse generation in this way does not cause any difficulties, since such devices are provided on every printing press anyway.

Since the resolving power of the scanned perforated disk 50 due to If there are limits to the specified dimensions, the one supplied by the button 49 is used Frequency preferably with a PLL circuit and a counter stage 52 in known Way multiplied, so that for example for 1 mm transported paper web 100 Impulses arise. One impulse thus corresponds to a paper web path of 1/100 mm.

The output of the pulse multiplier, which emits a pulse signal every 1/100 mm 52 is connected to the counting input of a group of pulse counters 28, 29, 30, 31 and 32, respectively created. The counters 28-32 also have control inputs that are on exit of the control unit 27 are present. The counter outputs are each to a comparator 33, 34, 35, 36 or 37 connected, the other inputs of which are a comparison signal from the control unit 27 is supplied. This comparison signal and the outputs of the comparators 33 - 37 are applied to the six inputs of an AND gate 38.

At the output of the 'ND gate 38, a start signal St appears, which the comparison logic, not shown, requests the position comparison of the two register aarken 11, 12 to carry out the corresponding readjustments to trigger on the pressure cylinders.

The operation of the device shown in Sig. 3 is as follows: It is assumed that the paper web 39 according to FIG. 1 under the optical heads 19, 20 runs through it in the direction of arrow-f, first the test mark 16 in the field of view of the optical head 19 occurs. As soon as this is the case, the control unit receives 27 a signal from the pulse shaping stage 42 which leads to the activation of the counter 28. This thus begins the pulses supplied by the pulse multiplier stage 52 to count.

While the counter 28 is still counting, the mark 17 enters the field of view of the optical head 20. This gives the control unit 27 via the pulse shaper stage 43 a signal which leads to the activation of the counter 29. Now also begins Counter 29 to count up the clock pulses supplied by stage 52.

The sixth step is that the trailing edge 23 of the test mark 16 passes under the optical head 19, whereby the end of the test mark 16 signals will. The control unit 27 now turns off the counter 28 and indicates at the same time the comparator 33 receives the command from the counter 28 measured length the mark 16 with the setpoint stored in the control unit 27 to compare. Is equivalent to the number of enumerated pulses within a specified tolerance range the preselected target value, this is reported back to the control unit 27, and the ongoing reading into the counter 29 is continued. The comparison shows however, that the number of pulses counted in the counter 28 does not match the setpoint value matches, all counters are reset to 0, and the one described The cycle starts again when the next mark is reached.

If the counter 28 shows the target value, the stopping of the Counter 28 of the counter 30 started, which is now the length of the gap 15 between the test marks 14, 16 determined. At the end of the step 15, the counter 30 is switched off and from the control unit 27 the comparison between the enumerated number of pulses and the Setpoint in comparator 35 commanded. If this comparison shows a discrepancy between the If the actual value is from the setpoint, all counters are set to 0 again. Is correct however, if the actual value contained in the counter 30 corresponds to the setpoint value, then it takes place at the same moment the activation of the counter 31, which shows the actual length the test mark 14 is determined.

The next step is that the control unit 27 via the pulse shaper stage 43 the end of the mark 17 is reported, whereby the counting process of the counter 29 ends will.

It now takes place in the same way as for the counters described above the comparison of the actual value and the setpoint value in the comparator 34. The result is either continuation of operation or resetting of all counters to 0.

Finally, the end of the marker 14 is signaled to the control unit 27, whereupon the counter 31 stopped and the comparator 36 the command is given to compare the actual value and the setpoint value. If they do not match, they will be all counters are set to 0 again, while the control unit if there is a match 27 now the'Zähler 32 activated, which the pulses while passing the bridge 13 enumerates.

As soon as the gap 13 has ended or the register mark 11 begins, the counter 32 is stopped and in the comparator 37 the comparison between actual and setpoint carried out. If they do not match, all counters are reset 0 is reset and no signal appears at the output of AND gate 38.

But if the last comparison in the comparator 37 also results in the agreement of setpoint and actual value, the signal is present at all inputs of the AND gate 38 on, and a start signal St appears at the output, which is no further here The comparison logic described causes the position comparison of the two register marks 11, 12 to be carried out.

If the signals from the pulse shaping stages 42, 43 are not in the If the prescribed sequence and pulse duration arrive, the one that has been started is repeated each time Readout cycle interrupted and all counters are set to 0.

While in the embodiment described above, the length the test marks and gaps are compared with a fixed target value, A comparison of the marks and gap widths with one another can also be carried out will. Instead of the clock generator that works proportionally to the path speed a clock generator running asynchronously to the web speed is then used. The clock pulses are then provided by a generator known functionality Delivered at a constant frequency. When the mark 16 is recognized in the reading lane 25 are in a first counter for the presence of the mark 16 in the field of vision Pulses from the generator are listed. The counter reading then forms the reference variable for the subsequent length measurement of the bridges 13, 15 or the test mark 14 inder Reading lane 25 or the mark 17 in reading lane 26. If, for example, is specified, that the width of the mark 17 and the bridge 15 are identical to the width of the mark 16 is and the width of the mark 17 and the gap 13 is twice as large as that of the Is mark 16, the counters assigned to marks 14 and pieces 15 must be used the same meter reading as that of the within a selected tolerance range Have mark 16 associated counters.

At mark 17 and gap 13, double the count must be reached will. The individual counters and the comparators are also activated here via a control unit as in the first example mentioned. Again, only if there is agreement an initiated identification cycle is continued between the setpoint and the actual value. If they do not match, the cycle is interrupted.

This method has the advantage that that in the first example optical buttons required for scanning a raster disk can be dispensed with. With strong However, variations in web speed must result in high counts must be worked, as there is also sufficient for the maximum path speed Resolution of the smallest mark must be given. At minimum train speed there will then be too high a number of single pulses with a wide one bark or wide gap are offered.

- patent claims -

Claims (14)

Claims 1. A method for identifying two on one running web along two reading tracks, register marks arranged next to each other, which by two juxtaposed, fixed optical scanning systems detected and examined for their relative position to each other, thereby g e k e n n z e i c h n e t that at least one of the two register marks (11, 12) a predetermined sequence of further test marks (14, 16, 17) and gaps (13, 15, 18) upstream which is in front of the register marks (11, 12) one after the other by the scanning systems (19, 20) are detected, and that the output from the scanning systems (10, 20) Signals examined for the presence of the predetermined sequence of test marks and gaps will. 2. The method according to claim 1, characterized in that g e k, e n n -z e i c h n e t that both register marks (11, 12) further test marks (14, 16, 17) and gaps (13, 15, 18) are connected upstream. 3. The method according to claim 1 or 2, characterized in that g e k e n n -z e i c h n e t that the length of the test marks (14, 16, 17) and gaps (13, 15, 18) with fixed setpoints are compared. 4. Process according to claim 1 or 2, characterized in that g e k e n nz e i c h n e t that the length of the test marks (14, 15, 17) and gaps (13, 15, 18) on the Existence of a predetermined relationship can be examined. 5. The method according to any one of claims 2 to 4, characterized g e -k e n n z e i c h n e t that the front and rear edges (22, 23) of the test marks (14, 16) in one Reading track (25) not with those (21, 24) in the other Reading track (26) coincide. 6. The method according to any one of the preceding claims, characterized g e it is not shown that one register mark (11) has two test marks (14, 16) and two gaps (13 - ', - 15) are connected upstream. 7. The method according to any one of the preceding claims, characterized g e no indication that the other register mark (12) has a test mark (17) and a gap (18) is connected upstream. 8. The method according to claim 6 and 7, characterized in that g e k e n n -z e i c h n e t that the test mark (17) assigned to the other register mark (12) extends over extends two of the one register mark (11) assigned test marks (14, 16). 9. The method according to any one of the preceding claims, characterized g e it is not shown that all test marks (14, 16, 17) together with one (all) the register marks-be printed. 10. Device for carrying out the method according to one of the preceding odors with two optical systems detecting the reading tracks, which are one of the emit a detectable brightness corresponding electrical signal, thereby g e k It is noted that the scanning system (19, 20) is connected to a control unit (27) in which the predetermined test mark-gap sequence is stored, and which at the beginning of each test mark or gap a counter (28, 29, 30, 31, 32) triggers to return to it at the end of the relevant test mark or gap stop and get one To trigger a comparison with the nominal length. 11. The device according to claim 10, characterized in that g e k e n n -z e i c h n e t that only one (13) of the immediately in front of the register marks (11, 12) A counter (32) is assigned to gaps. 12. The apparatus of claim 10 or 11, characterized g e -k e n n z e i c h n e t that at each counter (28-32) one acted upon by the control unit (27) Comparator (33, 34, 35, 36, 37) is connected. 13. The apparatus according to claim 12, characterized in that g e k e n n -z e i c h ne t that the control unit (27) and all comparators (33-37) to an AND gate (38Y are connected, at the output of which the identification signal is picked up. 14. Device according to one of claims 10-13, characterized g e k e n n z e i c h n e t that the frequency of the pulses fed to the counters of the web speed is proportional. 15, device according to one of claims 10-13, characterized g e k e n n z e i c h n e t that the frequency of the pulses supplied to the counters is constant and the count of the first counter (28) as a reference value for the subsequent length measurements is used.