WO2003093154A1 - Method and device for counting edges of products - Google Patents

Abstract

The invention relates to a method for counting edges (8) of products (1), particularly printing products, between a production process and a stacking process. According to the inventive method, the edges (8) of the products (1) are counted for a first time during or following the production process, whereby a first tally is obtained. The edges (8) are counted for a second time prior to a stacking process, whereby a second tally is obtained. Said two tallies are compared and a relative error value is determined from the two tallies.

Description

Method and device for counting edges of products

The present invention relates to a method and an apparatus for counting edges of products.

In print shops, printed products, such as advertising printed matter or magazines, are primarily produced using web printing machines, for example commercial web offset, newspaper and gravure printing machines. After the printing process, these web printing machines lay out the products in a scale-like manner, lying one above the other on a means of transport, such as a conveyor belt. Here it is said that the products are in the form of a so-called scale on the means of transport.

A delivery star is often arranged at the end of a printing press and creates the scale-like arrangement of the printed products when they are deposited. The products are placed on conveyor belts, transported further and further processed in this area in various ways, for example, trimmed, or provided with stickers, etc. Furthermore, defective products are also sorted out manually.

At the end of this further processing, the printed products are usually formed into stacks or bars, that is to say stacks which are pressed for a very long time and, if necessary, strapped and have a length of approximately 800 to 1200 mm. This stacking or staging Genetic formation takes place in so-called cross-layers or bar formers, which are also generally referred to below as stacking devices.

The operator of the printing press usually sets a certain number of printed products for the stacking devices which are to be contained in a package or a bar. In order to obtain the correct number of products in the package or bar after the further processing process, which also includes sorting out insufficient products, there is usually a device in or in front of the machines for stacking or forming bars to detect the incoming product edges.

Such counters, which can be mechanical, infrared or laser counters, for example, give an impulse signal to a control of the stacking machine, which thereby recognizes how many products have been fed into the stacking or bar-forming machine and when a package or one Rod is formed.

Such counters which can be used for this purpose and which recognize the edges of the products with the aid of a laser beam and its respective refraction are known, for example, from US Pat. No. 4,450,352 and US Pat. No. 4,778,986.

With such optical counters known from the prior art, the products are not actually counted, but edges are detected with the aid of laser beams. The colloquially known product counter only gives product edge impulses to the control of the packaging machine and this converts these impulses into a count value. The problem with these counters known from the prior art, however, is that the counters, for example, cannot correctly or not at all recognize very irregular flakes and, in particular, flakes with negative overlaps, that is to say underlaps. In the case of the optical counters, strong color assignments of the printed products can also lead to false impulses. These errors can lead to packages or rods that have the wrong number of products, but sometimes to a greater extent. However, such incorrectly stacked packages and bars lead to high additional costs.

If the packages are too large, the print shop delivers too many products to the customer, which means increased costs. However, if the packages are too small, customer complaints will result and the print shop will reprint the missing product quantity. However, this causes major disruptions in the operational process and an increased cost, since a separate print job has to be carried out for small quantities.

In addition, it is also possible to count the products mechanically. When using mechanical counters, it has proven to be disadvantageous that these mechanical counters have to be set manually in a production-specific manner. This is often neglected due to the effort and the necessary qualifications of the staff. At high production speeds, the mechanical parts of the mechanical counter can often no longer follow, which causes counting errors.

In principle, the mechanical counters also touch the scales. It has proven to be disadvantageous here that the mechanical contact can damage or move away and markings on the products.

In addition, it is also possible to count the printed products with a so-called printing machine clock pulse.

For example, the counting on the delivery star at the end of the printing press can be carried out in a simple manner with the aid of a light barrier when the products fall into the delivery star. However, this type of counting also has major disadvantages. On the conveyor line from the printing press to the stacking device, also referred to as just a stacker for short, it is sometimes possible to remove individual or several products lying one behind the other, so that gaps are created in the scale. However, these gaps are not taken into account when using the printing machine clock pulse since the counting has taken place beforehand. This leads to errors in the batch quantity and thus to the disadvantages already described above.

Based on this, it was an object of the present invention to provide a method and a device with which it is possible to count edges in a more reliable manner and to remedy the disadvantages of the prior art.

This object is achieved according to the invention by a method for counting edges of products, in particular printed products, between a manufacturing and a stacking step. A first counting of the edges of the products is carried out during or after the manufacturing process, as a result of which a first counting value is obtained. Before a stacking step, the edges are counted a second time, whereby a second count is obtained. These two count values are compared and a relative error value is preferably determined from them in a control device of the stacking device.

According to the present invention, a stacking step is to be understood to mean a stacking step of the products, such as the formation of bars or cross-laying in the case of printed products, or any other type of arrangement in order to bring the products into a transportable form.

With the method used according to the invention, it is now possible to solve the problems described above in more detail when removing individual or a plurality of printed products lying one behind the other after production and before stacking, which will be described in more detail below.

Such a method according to the invention can be carried out, for example, with a device according to the invention, namely a device for counting edges of products, in particular printed products, in particular with a method according to the invention, a first counting device being provided after the production process, followed by a transport of the Products to a stacking device is carried out, on a path to the stacking device or when entering a stacking device, a second counting device and a control device for comparing and processing the two received counting values is provided.

With the device according to the invention, the accuracy of the second counting device arranged on a path to the stacking device or when entering a stacking device can be monitored by means of the method according to the invention and warn the operator if a fault tolerance limit is exceeded. In addition, it is also conceivable that the counting error is corrected automatically.

Since, in a method according to the invention, in addition to the pulse of the first counter, which preferably represents the printing machine tacti pulse, the counting pulses of the second counter also go into a control device which has a microprocessor, a gap in the so-called scale can be detected by the second counter and thus the printing machine clock pulse is suppressed for the duration of the gap. Since the error measurement according to the method according to the invention is preferably carried out continuously, a further error limit can be used to decide whether the gap reported by the second counter is also credible. For example, up to 10% error, the absence of the counter pulse could be interpreted as a real gap. If the error lies above this value, the gap detection is switched off by the second counter, since the gap is then no longer credible.

Such an implementation of the method gives the operator a relatively imprecise result, but firstly he has a warning at his disposal and secondly he can continue to produce, even if the second meter is only working very poorly or is no longer working. As soon as the value falls below the limit error value, the signal from the second counter is used again. This ensures that the best counting type is always used.

Counting is usually done by measuring product edge pulse signals. According to the present invention, the control device is connected to the second counter and also the first counter, which supplies the product pulse of the printing press. The control device in turn outputs a product edge pulse to a control of the stacking device. The stacking device does not notice that the counting pulse does not come from the counter built into the stacking machine, but from the control device.

The two incoming counting pulses are preferably processed by averaging and then compared with one another. An error can then be calculated from this. For example, this could be defined as follows:

Error = (cycle _printing machine - cycle _count ι _Θr ) * 100%

1 a Kt printing machine

The current error rate, for example, is calculated approximately 5 times per second and displayed continuously. If an adjustable error tolerance is exceeded, for example in a range from 0.5 to 10% for a duration, preferably from 5 to 100 s or the duration of a predetermined number of pulses, preferably in the range from 10 to 1000, according to one preferred embodiment of the invention, a warning signal, for example a lamp or an acoustic signal, is triggered.

In addition, it is also possible for the method according to the invention to use the count value of the second counting process before a limit error value is exceeded and to use the count value of the first counting process after the limit error value has been exceeded. This means that the control device then receives the incoming printing press clock pulse of the first switches to the output connected to the stacking device.

After completion of the manufacturing process, the counting is preferably carried out by the second counting process, since the first counter no longer recognizes products.

In a device according to the invention, the first counting device is preferably a light barrier. However, any other suitable counting device could also be used, such as an ultrasonic sensor, an inductive proximity switch or a corresponding pulse from the printing press control.

The second counter device, on the other hand, is often a laser counter, but could also be an infrared counter and / or a mechanical counter.

In a device according to the invention, a further, preferably inexpensive counter, such as a light barrier, could preferably be provided in addition to the second counter. This light barrier can also detect a gap in the shingled stream. This further counter will also be connected to the control device.

Should the control device switch the printing machine pulse to the output connected to the stacking device because the laser counter works above the fault tolerance, then the laser counter is no longer used for gap detection, but only the light barrier. The automatic switching of the control device to the most favorable use of the impulses for the respective situation ensures the best possible product safety. In the event that the control device uses the pulse of the first counter, problems can arise at the end of production because the first counter no longer delivers pulses, although the possibly very long transport route between the printing press and the stacking device is still full of printed products, which still run into the stacking device and possibly further finishing machines. Since no more pulses from the first counter reach the control device and the stacking device also no longer receives any pulses, the products run into the stacking device, for example, via a conveyor belt, although these machines do not carry out the processing steps required for this. This leads to sometimes considerable malfunctions and even damage to the machines. In such a situation, the control device therefore automatically switches over to the second counter, even if it operates above the error limit.

In order to also cover, for example, the case that the laser counter is defective or delivers completely incorrect values, an additional pulse generator can be connected to the control device, which outputs pulses proportional to the conveyor belt. To simulate an old average clock ratio, a belt pulse from the conveyor belt can be picked up and fed into the microprocessor provided in the control device.

If the printing process is now ended or interrupted, the pulse of the first counter, the printing machine clock pulse, fails, while the pulse or clock continues at the input to the stacking device. In this case, the control device is constantly on during normal operation average ratio of the printing machine clock pulse and the belt cycle is determined and can therefore simulate a printing machine clock pulse at the end or when production is interrupted from the determined so-called belt cycle, so that the correct clocks or counts are passed on to the stacking device with a good approximation.

In the device according to the invention, as described here, the individual components of the device can be arranged as desired. So several or all of them

Device sections can be accommodated in a common housing or all can be arranged individually.

Further advantageous refinements of the present invention result from the subclaims and the description.

For a more detailed explanation, the invention is described in more detail below on the basis of preferred exemplary embodiments with reference to the drawing.

The drawing shows:

Figure 1 shows a scale in a side view;

Figure 2 shows a scale in a plan view;

FIG. 3 shows an area between a printing press and a stacking device, the printing process still being run;

FIG. 4 shows an area between a printing press and a stacking device according to FIG. 3, the printing process being completed; and Figure 5a to 5c Various controls for devices according to the invention.

FIGS. 1 and 2 show the scale-like arrangement of printed products 1, the so-called scale 2, once in a side view in FIG. 1 and in a top view in FIG. 2. With reference to these two figures, the problem of counting the Printing products 1 when laid out as a flake are explained according to the methods of the prior art.

In FIG. 1, the scale is arranged on a conveyor 3, such as a conveyor belt, and is moved in the direction of the arrow 4. Furthermore, a counter, here a laser counter 5, is arranged, which counts the printed products 1.

It can be seen in FIG. 1 that if the scale 2 has irregularities, such as negative overlaps 6, it is not possible to count the individual printed products 1, since the laser counter 5, which can only recognize edges 8, recognizes the overlapped product not recognized, since no edge 8 is visible in the direction of the laser beam 5A.

FIG. 2 shows the problem of strong color assignments of printed products 1. If, for example, the printed products 1 have black areas 7 with a strong contrast to the adjacent areas, this can lead to an incorrect count, since the optical laser counter 5 believes that it recognizes an additional edge. FIG. 3 shows an area between a printing machine 23 and a stacking device 9, that is to say after the completion of the printed products 1 up to the stacking of the printed products 1 in a stacking device, here a stacker 9.

After their production, the printed or printed products 1 are transported in the direction of the arrow 10 and laid out as a scale 2 by a delivery star 11 which rotates in the direction of the arrow 12. According to the preferred embodiment shown, the laying takes place on a conveyor belt 3 which moves in the direction of arrow 13 and feeds the scale to the stacker 9. Between the delivery star 11 and the stacker 9, a person 14 is shown schematically who can sort out faulty printed products. Furthermore, in this area, the products are often finished, such as cutting, with stickers.

A first counting device, a light barrier 15, is arranged in front of the delivery star 11, which supplies a pulse for counting the printed products 1 that have been laid out. A second counter is arranged shortly before the printing products 1 are stacked. According to the described preferred embodiment of the present invention, this is a laser counter 16. This counter 16 also delivers a pulse.

All these pulses, that of the first light barrier 15, the laser counter 16, the second light barrier 17 and the additional pulse generator 19 are fed to a control device 20 in which the pulses are processed with the aid of a microprocessor 21. The control device 20 controls the stacking device, here the stacker 9, by turning on adapted the respective situation, passes selected impulses to the controller 24 of the stacker 9. In this way, a product count with as few errors as possible can be obtained.

The control device 20 in turn outputs a product edge pulse to a control of the stacker 9. The stacker 9 does not notice that the counting pulse does not come from the built-in counter 16, but from the control device 20.

The two counting pulses coming into the control device 20, that of the light barrier 15 and the laser counter 16, are preferably processed by averaging and then compared with one another. An error can then be calculated from this, as has already been described.

The current error rate is calculated approximately 5 times per second and displayed continuously. If an adjustable error tolerance, for example 1%, is exceeded for a duration of at least 30 s, a warning signal, a lamp 22, is triggered in accordance with the embodiment of the invention shown.

In addition, it is also possible for the method according to the invention to be counted by the laser counter 16 before the limit error value is exceeded and by the light barrier 15 after the limit error value has been exceeded. This means that the control device 20 first switches the pulse of the laser counter 16 and, after the limit value has been exceeded, the incoming printing machine clock pulse of the light barrier 15 to the output connected to the stacking device 9. In a device according to the invention, a light barrier 17 is provided in addition to the laser counter 16. This light barrier 17 can now recognize a gap in the scale 2 or the end of this. For this purpose, the conveyor belt 3 could, for example, have openings in the region of the light beam 18 of the light barrier 17, so that the light beam 18 can pass through the conveyor belt 3 if the scale 2 has a gap.

Should the control device 20 use the printing machine pulse of the counter 15, since the laser counter 16 works above the fault tolerance, then the laser counter 16 is no longer used for gap detection, but only the light barrier 17. The automatic switching of the control device 20 to that of the respective one Favorable evaluation situation of the impulses guarantees the best possible product safety.

In the event that the control device 20 uses the printing machine clock pulse of the counter 15, problems can arise at the end of production of the printing process of the printing machine. The situation that the printing process is complete but the stacking has not yet ended is shown in FIG. 4. In this situation, the printing machine cycle no longer provides impulses, although the possibly very long transport route between the printing machine 23 and the stacker 9 is still full of printed products 1 which still enter the finishing machines, such as the stacker.

In such a situation, the control device 20 can automatically switch over to the second counter 16, even if it operates above the error limit. In order to also cover, for example, the case where the laser counter 16 is defective, an additional pulse generator 19 can be connected to the control device 20, which outputs pulses proportional to the conveyor belt. In order to simulate an old average cycle ratio, a belt pulse from the conveyor belt 3 can be recorded during normal operation and fed into the control device 20.

If the printing process is now ended or interrupted, the printing machine clock pulse fails, while the clock continues at the input to the stacking device 9. In this case, the control device 20 has continuously determined an average ratio of the printing machine clock pulse and the belt clock during normal operation and can therefore simulate a printing machine clock pulse at the end or when production is interrupted from the determined belt clock so that the correct clocks are passed on to the stacking device 9 with good approximation become.

FIG. 5 again shows various possible situations for the pulse feed into the control device 20.

FIG. 5 a shows the situation that pulses from the first counter, the light barrier 15 and the second counter, the laser counter 16 are fed into the control device 20 and the error between the two values is calculated continuously and a lamp 22 is activated after a limit error value has been exceeded becomes. In this situation it is also possible that up to 10% error the absence of the counter pulse is interpreted as a real gap. If the error lies above this value, the gap detection is switched off by the second counter, since the gap is then no longer credible FIG. 5b shows the structure of the control device 20, in which, in addition to the structure shown in FIG. 5a, the information from the second light barrier 17 is fed into the control device 20. This light barrier 17 can detect a gap in the scale 2 and when using the count value of the first counter 15 this pulse is not taken into account for the duration of the gap.

In FIG. 5c, the conveyor belt pulse is also fed into the control device 20. In particular, at the end of production, with such an arrangement, when using the pulse of the first counter 15, which no longer recognizes products, a simulated pulse can be used until the end of the arrival of the products 1 in the stacking device 9. This has already been explained in more detail with reference to FIG. 4. The light barrier 17 then recognizes the end of the run-in of the products 1 into the stacking device 9.

Depending on the situation, in the method described in detail, a pulse 25 is output from the control device 20, which controls the stacking device 9 most precisely.

Claims

claims 1. A method for counting edges (8) of products (1), in particular printed products, between a manufacturing and a stacking step, comprising the steps: First counting process of the edges (8) of the products (1) during or after the manufacturing process, whereby a first Count value is obtained; Second counting of the edges (8) before a stacking step, whereby a second count is obtained; Comparing the two counts obtained; and Find a relative error value from the two Counts. 2. The method of claim 1, wherein at least one count is obtained by measuring product edge pulse signals. 3. The method of claim 1 or 2, wherein a warning signal is triggered when a limit error value is exceeded. 4. The method according to claim 3, wherein the count value of the second counting process is used before the limit error value is exceeded, and the count value of the first counting process is used after the limit error value is exceeded. 5. The method according to any one of claims 3 or 4, wherein the limit error value is in a range from 0.5 to 10% for a duration of 5 to 100 s or a predetermined number of pulses, preferably in the range from 10 to 1000. 6. The method according to any one of the preceding claims, wherein after completion of the manufacturing process, the count value is obtained by the second counting process. 7. The method according to any one of the preceding claims, wherein after detection of a gap by the second counting process, the count value is obtained by the second counting process. 8. The method according to any one of the preceding claims, wherein an average cycle ratio of the edges (8) of the products (1) is simulated after completion of the manufacturing process until all products (1) are stacked. 9. The method according to claim 8, wherein a pulse of a means of transport (3) is recorded to simulate the old average clock ratio and is fed into a microprocessor (21) in addition to the other count values. 10.Device for counting edges (8) of products (1), in particular printed products, in particular in a method in one of the preceding claims, a first counting device (15) being provided directly after the manufacturing process, on a path via a transport device (3) to a stacking device (9) or when entering the stacking device (9), a second counting device (16) and an evaluation device (20) for comparing and / or processing the two received counting values are provided. 11.The device according to claim 10, wherein the first counting device (15) is a light barrier, an ultrasonic sensor, an inductive proximity switch and / or a corresponding pulse from the printing press control. 12.Device according to claim 10 or 11, wherein the second counting device (16) is a laser counter, an infrared counter and / or a mechanical counter. 13.The device according to one of claims 10 to 12, wherein in addition to the second counting device (16), a further counting device (17), in particular a light barrier, is provided. 14.The device according to one of claims 10 to 13, wherein one or more count values are received as pulses from the counting devices (15, 16 and / or 17) and a microprocessor (21) is provided for comparing and / or processing the count values. 15.The device according to one of claims 10 to 14, wherein for transporting the products (1) from the manufacturing process to Stacking device (9) a conveyor belt (3) is provided. 6.Device according to one of claims 10 to 15, wherein several or all device sections are accommodated in a common housing.