EP2660172A2 - Wrong sheet control for a sheet-fed printing press - Google Patents

Abstract

The press has a wrong sheet sensor comprising a measuring unit (11) for detecting a wrong sheet e.g. twin sheet. The measuring unit is associated with moving substrate sheets (B1-B3). A timing roller (3) sequentially conveys the substrate sheet, which is isolated from a sheets stack. A processing machine is provided in combination with a band roll (2) associated with a band desk (1) and/or a carrier roll. The measuring unit is provided for instrumentation acquisition of a support height (X) of the timing roller, the band roller or the carrier roller.

Description

The invention relates to a false-sheet control in a sheet-processing machine, in particular a sheet-fed press, according to the preamble of claim 1.

In known sheet-processing machines, such as sheet-fed presses, substrate sheets are each held ready for processing in a feeder stack. The substrate sheets are formed by means of suction devices, usually designed as a suction head with separating and transport suckers, individually lifted from the feeder stack and conveyed by means of a clock conveyor on a belt table. The clock conveyor is normally designed as an arrangement of at least two clock rollers in a symmetrical arrangement to the machine width over a belt roller or transport roller. The clock rollers are discontinued by a clock shaft to the beat of the sheet-processing machine on the belt or transport roller and clamp there the substrate sheet individually or in a submerged position. As a result of the rotational movement of the belt or transport roller, the substrate sheets are then moved forward at a predetermined speed in synchronism with the machine operation. About the belt table, the substrate sheets are then stored on a trained as an investment table application device for aligning the substrate sheet. From the feed table, the substrate sheets are finally fed to a sheet feeder of sheetfed presses.

The lifted from the feeder pile substrate sheet are supplied via the belt table usually in shingled sheet as a scale flow of the sheet feeder. The scale flow is formed in the singulation of the sheet stack by the front end of a subsequent sheet are pushed in each case in the area of the clock conveyor with raised clock rollers of the suction under the end of the advance substrate sheet.

To ensure proper operation of a sheetfed press is important that no so-called false sheets occur.

A false arch is about a double sheet of two congruent or possibly slightly shifted to each other superimposed substrate sheet whose supply can lead to the same in the sheet-fed printing machine damage or disturbs the smooth implementation of the print job. False sheets are substrate sheets that differ in one property from a properly fed substrate sheet. In addition to double sheets, this includes missing sheets, ie non-existing substrate sheets, multiple sheets of more than two substrate sheets, oblique sheets whose leading edge deviates from the ideal position, early sheets arriving before a target time, late sheets arriving after a target time, thick sheets with larger or thin sheets with a smaller arch thickness than the default corresponds.

Usually, mechanically acting devices are used for double sheet detection, which mechanically scan the scale flow to be checked. In this case, a very accurately manufactured scanning roller, which is connected to a microswitch, additionally rolls on the surface of the scale flow in addition to the clock rollers. In this case, marks are caused by the cam follower on the substrate sheet, although the Abtastrolle is hired only with a minimum force against the scale flow in order to obtain a meaningful control result. A disadvantage is the increased effort for the high-precision production of the scanning roller and the parallel arrangement of several roller systems for conveying and monitoring.

In this context is from the EP 1 172 317 B1 known, double sheet not to capture the clock role but separately. At the beginning, the device learns to touch the contour of the contour and dynamically adjusts the roller height with piezo actuators for the further course of the sheet monitoring. The clock roller then no longer touches the arc current in the normal case. Here reference is also made to the errors to be determined, which are marked as early, late and oblique. It is a probe element provided with an actuator can be moved in sheet travel direction. The application can also be done in a fixed position.
Furthermore, a measurement of the contact pressure of the clock roller can be provided. In this case, an inductive measuring system or a force measuring system can be provided. Touching measurement should be position-controlled, with the contour of the arc current to be traced.

From the DE 100 21 629 A1 is a device for double sheet control with an additional probe element in the form of a role associated with a switching element known. It should therefore be provided at least two sensing elements, with a manual adjustment. The probe element as a roller does not rotate during functional operation when scanning a sheet flow. The measurement is uncertain.

Out DE 10 2004 053 891 A1 Another device for double sheet control is known. This is about the double-bow sensing using capacitive measuring principles. The measured values obtained are recorded continuously on the basis of machine angles. In this case, a control is provided which is used to evaluate the signals in order to automatically calibrate the system thus operating. The measurement takes place in a separate area of the sheet conveying and requires additional complex measuring means.

From the DE 10 2007 003 001 A1 Another device for Doppelbogenabtfühlung is known. The solution relates to a false-arc sensor which has a measuring capacitor for false-arc detection. In this case, the measuring capacitor is formed by two measuring electrodes which lie opposite one another and thus jointly define a capacitor space, and substrate sheets are moved through the capacitor space for false-arc detection. It is particularly disadvantageous here that although the clock roller is mentioned as the measuring location, it only fixes the scale flow in order to then measure it capacitively in parallel. The metrological effort is increased because the measuring system also directly measures the scale flow, the measurement configuration is constantly changing.

All currently implemented double sheet detectors are not fully usable. The spectrum of physical substrate properties shows specific deficits here. In addition, all executed variants must be calibrated manually before commissioning. The previously executed, tactile detection of the scale flow thickness produces markings, is mechanically extremely complex and can only be adjusted manually.

The object of the invention is therefore to improve a device for false-sheet detection and in particular for Doppelbogenabfühlung, with a substantial simplification of the device in design and operation is sought.

According to the invention the object is achieved with the features of claim 1.

According to the invention, a false-arc sensor is provided in a sheet-fed printing press which has a measuring device for false-sheet detection in conjunction with at least one control roller. The substrate sheets to be monitored are moved by at least one clock roller in a scale flow to the sheet-processing machine by the clock rollers interacting with a belt drum or transport roller associated with a belt table. The measuring devices are used to detect the support height of the clock rollers on or above the belt roller or transport roller, starting from an idle roller. If at least two measuring devices are arranged during sheet delivery, then the contour of the scale flow can be scanned in at least two measuring tracks lying in parallel.
Advantageously, the measuring device associated with a clock roller is designed to be magnetically active, the position of a signal magnet being scanned by one or more measuring devices designed as a Hall sensor. Such a measuring device is very reliable and robust.
On the basis of the measuring method, the measuring device can be carried out in an advantageous manner self-adjusting and operated fully automatically, being self-calibrated and automatically by signal processing algorithms.

In a particularly advantageous embodiment, the measuring device can be retrofitted to the said machines and / or interchangeable with conventional devices for Doppelbogenabtfühlung.

The functionality of the measuring device is formed in a highly accurate manner by redundantly recorded measured values for position information and by the use of signal-processing, recursive algorithms. In this way, influences of inaccuracies of each mechanically individual constellation and of devices executed with inaccuracies can be eliminated. By means of the device according to the invention, it is furthermore possible by evaluating the clock-roll height signals to determine all information relevant for further signal processing, in particular also machine angle information required for the position assignment.
Furthermore, the measuring device can be adapted to changes in substrate thickness in an automatic sequence.
The clock rollers for conveying the substrate sheet from the sheet feeder of the sheet-fed press perform a first mechanical access a touch movement. The tactile movement takes place for contacting the underlying lying as a sheet flow arc single sheet. Here, the two rollers are raised for a machine angle of about 100 °.
During this time, a subsequent substrate sheet is pushed by a separating device of the sheet feeder under a leading substrate sheet. Then the clock rollers are lowered onto the scale flow against the belt roller or transport roller and clamp the blade flow in frictional engagement with the transport roller. The clock rolls are sufficiently soft and geometrically designed so that marks on the substrate sheet do not occur.

If the thickness of the substrate sheet conveyed from the sheet feeder in a shingled arrangement to the machine is recorded from the first sheet, a fully automatic false-sheet recognition becomes possible. The associated measurement information is available in normal operation with the execution of about 3 machine revolutions. In continuous operation are otherwise in the transport area between the feeder and the bow processing Machine constantly about 5 sheets. Thus, the state of the present in the scale flow substrate sheet is already known at the start of production before the substrate sheets are taken over by a sheet feeder, such as a pre-gripper, for transfer to the sheet-processing machine. In this case, the measurement signal, which corresponds to the total thickness of the superimposed substrate sheet, is detected continuously and stored after appropriate processing in a sequential memory. A software algorithm recursively evaluates the waveform and determines from the present measurements whether there have been any false scores at any time in the scanned stream scan. Furthermore, it is reliably detected where the false bows are present in derivation from the contour of the scale flow in the further course of the sheet transport at a certain time.

So for a secure function is of fundamental importance that a timely provision of the evaluation result is made possible, the results must be present before recognized as a false sheet substrate sheet can be promoted in the sheet processing machine. This ensures that machine locking devices provided for machine protection reasons still function reliably before a false-arc is fed into the machine and can possibly cause damage.

A reference of the signal acquisition to the machine cycle is possible by synchronous recording of machine angle information or recalculation on the basis of measured value information which is characteristically present in the measuring signal. For this purpose, the Absetzpunkt the clock rollers is suitable as the beginning of a bow cycle, which is present at certain machine angles per machine revolution.

Figur 1

eine erfindungsgemäße Abtasteinrichtung,

Figur 1A

ein Detail der Messvorrichtung gemäß Ausschnitt U in Figur 1,

Figur 2

einen schematischen Signalverlauf bei einem Bogenlaufstart und

Figur 2A

schematische Messpositionen in einer Anordnung nach Figur 1 oder 2.

An embodiment of the invention will be explained in more detail with reference to drawings. Showing:

FIG. 1

a scanning device according to the invention,

Figure 1A

a detail of the measuring device according to section U in FIG. 1 .

FIG. 2

a schematic waveform at a sheet run start and

FIG. 2A

schematic measuring positions in an arrangement according to FIG. 1 or 2 ,

In FIG. 1 schematically a device for conveying sheets and detecting the sheet position of the sheet is shown. The sheets may be formed as a substrate sheet of paper, plastic, cardboard or metal, and are shown here on a part of their transport path from a sheet feeder in a sheet transport direction R. The acquisition of the sheet position refers to single sheets of a lying below sheet flow. The desired information about the sheet position are derived quantities from the signal curve of a thickness measurement of the underlying sheet flow or imbricated flow.

In FIG. 1 Substrate sheets B1, B2, B3 are indicated, which are fed in the sheet transport direction R of the measuring and conveying device, after they have been previously separated in the sheet feeder. The sheets B1, B2, B3 are then transported via a belt roller 2 by means of a control roller 3 on a conveyor table 1 and then forwarded on the conveyor table 1 to the subsequently arranged sheet processing machine.
When conveying in the form of a scale flow, the substrate sheet overlap depending on a mostly machine-specific predetermined scale spacing of the leading edges of the substrate sheet. The coverage is dependent on the ratio of the scale spacing and the length of the substrate sheet.

In FIG. 1 In the scale flow, a single layer W1, a double layer W2 and a triple layer W3 of the successive substrate sheets B1, B2, B3 are shown with respect to the position between the take-up roller 3 and the belt roller 2. For isochronous promotion and at the same time to obtain the measured values, the clock roller 3 is placed on a timing lever 4 at regular intervals in time with the sheet-processing machine on the belt roller 2. For this purpose, the clock roller 3 is connected to the timing lever 4 via an axis 5 movable with a holder 6. The holder 6 is preferably fixed in the circumferential position adjustable on a clock shaft 7. The clock shaft 7 is driven synchronously with the power stroke of the sheet processing machine in cyclic movements Y.

In this case, in each case at the beginning of a working cycle in the sheet conveying the take-up roller 4 is placed on the resting on the belt roller 2 substrate sheet. Thereafter, the clock roller 3 is in cyclic intervals during the delivery period on the scale flow and thereby scans its thickness profile.
The clock roller 3 is supported via the timing lever 4 by means of a spring 9 relative to a holder 8 on the holder 6 and can thus perform a flexible tactile or pressure Z on the holder 6 relative to the band roller 2. The rest position of the timing lever 4 in the lifted by the clock shaft 7 of the belt roller 2 state is defined by a mounted on the holder 6 adjustable executed stop 15. This can be set relative to each other to an exact same key height when using multiple sensing devices all the clock roles involved.

When lowering the timing lever 4 by the movement of the clock shaft 7, the control roller 3 is lowered to a maximum of the band roller 2. Depending on the number of superposed there substrate sheet of the timing lever 4 moves more or less against the force of the spring 9 against the direction of rotation Y of the clock shaft 7 on the axis 5. The spring 9 holds the clock roller 3 against the belt roller 2 or just there resting sheet B1 - B3 in plant and ensures that the total thickness of the existing sheet layers can be measured accurately.

For fast and reliable measurement of the thickness of the sheet layers on the band roll 2 is a measuring device 11, which has one or more Hall sensors 11.1, 11.2 and is attached to the holder 6. The measuring device 11 cooperates with a signal magnet 10, which is attached to the clock roller 3 opposite end face of the timing lever 4. Thus, the measuring device 11 detects the actual position of the timing lever 4 and the control roller 3. It is advantageous that the measuring device 11 can be coupled directly to the already existing transport element of the control roller 3. In this case, the value of the altitude X of the control roller 3 with respect to a support on the belt roller 2 is used as a measured variable. The change in the altitude X indicates the functional cycle of the control roller 3 and is related to a currently required product measuring range. The product measuring area extends from the band roller 2 without sheet assignment in the normal case with a maximum measuring path of up to three sheet thicknesses of the currently processed substrate sheet. However, it must also be able to include at least four arch thicknesses during measurement operation, when, for example, double sheets pass through the measurement position
An up-to-date adaptation of the required product measuring range, which correlates to a specific production cycle, is carried out automatically by suitable standardization steps of the measuring software.

The measuring device 11 has a maximum measuring range S, which can be swept by the signal magnet 10. Depending on the starting position of the timing lever 4, a zeroing is automatically recorded by detecting a movement of the control roller 3 over at least one full revolution. In order for dimensional inaccuracies of the control roller 3 are also detected and can be taken into account in the evaluation of the measured signals.
The clock roller 3 runs at production start initially on the belt roller 2, without a substrate sheet would be transported. Thus, the later movements by the incoming substrate sheet can be identified as measured values relative to this initial value.
By means of a continuous scan, a continuous measured value profile for the substrate sheet supplied via the belt roller 2 is obtained as a sheet flow and its respectively particular position with respect to the sheet flow, the product measuring range being within the measuring range S.

In Figure 1A is in accordance with a section U from FIG. 1 the measuring device for detecting the altitude X of the control roller 3 in the view of the end face of the timing lever 4 is shown. The measuring device 11 is attached to the holder 6 and has two sensors in the form of Hall sensors 11.1 and 11.2, which extend parallel to each other along the measuring range S. The Hall sensors 11.1, 11.2 are arranged fork-shaped on the underside of the measuring device 11. At the timing lever 4, the signal magnet 10 is fixed frontally, which projects into the space between the two Hall sensors 11.1 and 11.2 inside.
By moving up and down during the transport cycle of the timing lever 4 when rolling the clock roller 3 on the scale flow is the measuring movement generates the signal magnet 10, wherein a constantly applied measuring signal of different intensity is generated. The double arrangement of the Hall sensors 11.1 and 11.2 increases the signal security. wherein the double signal detection by the two Hall sensors 11.1 and 11.2 is used for this purpose. During signal acquisition, the measurement signals of both Hall sensors 11.1 and 11.2 are added up to form a total measurement signal. At the same time position changes of the signal magnet 10 are compensated by movement tolerances on the axis 5.

The measurement signal can be linked to a machine angle signal for interpretation. Preferably, however, the machine angle is determined as part of the entire measurement signal. In this case, based on an evaluation by means of an algorithm, the measurement signal can be broken down into virtually any number of discrete values for individual measurement steps on the basis of an evaluation based on a zero signal which is constantly recurring at the beginning of a measurement cycle. These measured values can then be used for recycling in the sheet travel monitoring.

To complete the measured value profile several units with clock rollers 2, timing lever 4 and measuring device 11 on the clock shaft 7 next to each other arranged (see FIG. 2A ) become.
Thus, from the respective measured value profiles in corresponding measuring tracks of the measuring devices 11 above the scale flow, also further changes of relative positions of the transported substrate sheets can be detected on the basis of the identification of the sheet edges.
For example, a sheet edge must then be inclined relative to the sheet transport direction R if the measured values of one of the measuring devices 11 normalized for a certain machine angle come sooner or later than the edge of a second measuring device 11 arranged in parallel than those of a first measuring device 11 With regard to their overall behavior during sheet transport, they can be identified as arriving too early or too late if both normalized measurements of the two or more measuring devices are identified as being too early or too late with respect to a particular machine angle.

Through a so-called recursive evaluation of the measurement signal from the sampling of the surface of the underlying lying arc current (scale current), the calculation of discrete signal values of a single substrate sheet is possible. The evaluation of the scale flow is therefore independent and thus automatically adaptable to the dimensions of the printing material and its characteristics.

In FIG. 2 The identification of the characteristic values of the sheet transport is explained in more detail on the basis of a scheme for the measured values for the altitude X of the take-off roller 3. The scheme of FIG. 2 shows that the Boigernfassung not only on a belt roller 2 of the conveyor table 1 is executable, but also on one of the belt roller 2 upstream transport roller 12 by the clock roller 3 of this transport roller 12 is assigned.

In FIG. 2A the assignment of two measuring devices 11 to holders 6 on a clock shaft 7 with respect to a transport roller 12 is shown. The clock rollers 3 on the timing levers 4 set within each a measuring track V1 and V2 on the scale flow on the substrate sheet, which is guided by the transport roller 12.

For a better understanding, the example of a situation of "start of production" is based on FIG. 2 described below.

After a switch-on signal, the separation of substrate sheets from a stack of sheets in a sheet feeder begins. With the sheet separation begins the clock movement of the clock rollers 3, which first put on the empty transport roller 12 and thus provide an output signal for the state without substrate sheet.

Thereafter, at a certain specified machine angle with respect to the sheet processing machine, a first singular substrate sheet (see sheet B1 in sheet W1 in FIG Fig. 1 ) pushed under the clock rollers 3. Quasi simultaneously the clock rollers 3 are lowered, wherein the first substrate sheet clamped against the transport roller 12 and the associated altitude X of the control roller or clock rollers 3 is measured over the transport roller 12 by means of the measuring devices 11.

Thus, the sheet transport continues, wherein after a further machine revolution, a second separated substrate sheet (see arc B2 in Fig. 1 ) is pushed under the clock rollers 3, so that there is then a double layer of substrate sheet (see sheet B1, B2 in position W2 in Fig. 1 ). This is followed by a third arc which results in a threefold sheet position in a certain area (see sheets B1 - B3 in position W3 in FIG Fig. 1 ).
During the continuously repeating transport cycle, the timing rollers 3 are raised and lowered once for each substrate sheet. Thus, in continuous operation two or three substrate sheets are clamped against the transport roller 12 and the associated altitude X of the control roller / clock rollers 3 on the transport roller 12 is measured by means of the measuring devices 11.
The measurement is carried out continuously, wherein a continuous measurement signal from the Hall sensors 11.1 and 11.2 is present, which can be sequentially recorded.

The measured values are fed to a microcontroller 13 which comprises a measured value recording, a computer and a measured value evaluation. The microcontroller 13 is coupled to a machine control 14 of the sheet-processing machine, so that good signals or error signals can be sent to the machine control 14. As a result, safety devices of the machine can be switched in good time.

The microcontroller 13 begins exactly when feeder and transport roller 12 are put into operation to record the signals with respect to the clock roller height X against the empty transport roller 12. The measured values are stored sequentially in a memory of the microcontroller 13. On the basis of a machine angle predetermined by the sheet-processing machine or, according to calculations on the previously recorded signal from the height information, in each case substantially the same number of measured values, such as 100 or more, per machine revolution are stored. From the accumulation of these measured values or calculated values, the measuring arrangement calibrates itself automatically. In this case, it is concluded from the initial value of the scan on the empty transport roller 12 to the zero position. Furthermore, from the identified measured value levels and the position of the level transitions, the thickness of a single sheet and the Number of superimposed sheets calculated and the location of recognizable sheet edges, preferably leading sheet edges are identified.

With this information, the signals identifying a single sheet can be determined in a redundant manner and this value is automatically stored to evaluate the number of sheets.
The foremost or first sheet or sheet is located in known conveyors of the type described herein at a known distance from the registration position of the sheet processing machine. This distance can be defined as the number of machine revolutions. Therefore, it can be retrospectively determined whether in the course of sheet transport already false bows, especially double sheets, have been present and where they are currently in the sheet transport. So there is still enough time for this case to stop the sheet processing machine.

1. 1. Höhenmessung der Taktrollen 3 gegenüber der Bänderwalze 3 oder Transportwalze 12, für einzelne oder auch alle vorgesehenen Taktrollen 3
2. 2. Taktrollenhöhe X wird mittels eines magnetischen Wegsensors erfasst, der selbstjustierend einsetzbar ist
3. 3. maschinenwinkelsynchrone Messwerterfassung mit automatischer Anpassung an die Maschinengeschwindigkeit; Winkelinformation wird aus vorliegendem Messsignal berechnet oder Nutzung von externem Winkelgeber
4. 4. Erfassung redundanter Informationen der Dicke des Schuppenstroms durch Messwertauflösung der Werte bei Bewegung der Taktrollen 3 innerhalb eines Schuppenabstandes; so erhöht sich durch Vergleichswerte die Sicherheit der Bewertung der Messwerte zur Bogenstromstruktur deutlich.
5. 5. Weitere vorteilhafte Wirkungen:
   • Algorithmisch berechenbare Eliminierung systematischer und stochastischer Störsignale
   • Vollautomatische Betriebsweise
   • Eignung für alle Bedruckstoffe - ohne Ausnahme
   • Algorithmen zur Anpassung an Bedruckstoff- Dickenschwankungen
   • Potential zur Überwachung und Meldung jeder Falschbogencharakteristik (Doppelbogen, Früh-, Spät-, Schrägbogen)
   • Nachrüstbarkeit an konventionellen Takteinrichtungen
   • Verwendung eines äußerst robusten und störsicheren Messsystems in Form der Hallsensoren

The following facts can be seen as core features of the invention:

1. 1. Height measurement of the clock rollers 3 with respect to the band roller 3 or transport roller 12, for individual or all provided clock rollers. 3
2. 2. Clock roller height X is detected by means of a magnetic displacement sensor, which is self-aligning used
3. 3. machine-angle-synchronous measured value acquisition with automatic adaptation to the machine speed; Angle information is calculated from the existing measurement signal or use of external angle encoder
4. 4. acquisition of redundant information of the thickness of the scale flow by measuring value resolution of the values when moving the clock rollers 3 within a scale distance; For example, the reliability of the evaluation of the measured values relative to the arc current structure is significantly increased by comparison values.
5. 5. Further advantageous effects:
   • Algorithmically calculable elimination of systematic and stochastic interference signals
   • Fully automatic mode of operation
   • Suitability for all substrates - without exception
   • Algorithms for adapting to substrate thickness variations
   • Potential for monitoring and reporting of each false-arc characteristic (double-sheet, early, late, oblique sheet)
   • Retrofittability to conventional clock devices
   • Use of an extremely robust and interference-free measuring system in the form of Hall sensors

LIST OF REFERENCE NUMBERS

1 belt table 2 bands roll 3 synchronizing roller 4 stroke lever 5 axis 6 bracket 7 clock wave 8th support 9 feather 10 signal magnet 11 measuring device 11.1 Hall sensor 11.2 Hall sensor 12 transport roller 13 microcontroller 14 machine control 15 attack X measuring height M0 machine revolution to MXX machine revolution B1 - B3 substrate sheet W1 - W3 quires R Sheet running direction S measuring range U neckline V1 measuring track V2 measuring track Y Clock movement of the clock shaft. 5 Z Measuring movement of the timing lever 4

Claims (10)

Sheet-fed press, with a false-arc sensor, wherein the false-arc sensor has a measuring device (11) for false-sheet detection, wherein the measuring device (11) is associated with the moving substrate sheet (B1-B3) for false-sheet detection, characterized
in that at least one control roller (3) is provided for the sequential feeding of substrate sheets which have been separated from a sheet stack and to a sheet-processing machine in conjunction with a belt roller (2) and / or a transport roller (12) associated with a belt table (1) and that one or more measuring devices (11) for metrological detection of a support height (X) of the or all the clock rollers (3) on the belt roller (2) or transport roller (12) are provided. Device according to claim 1, characterized in that the measuring device (11) is a non-contact scanning the position of the or all the clock rollers (3) characterizing element. Device according to claim 1 or 2, characterized in that the measuring device (11) for detecting the position of the or all the clock rollers (3) is designed to act magnetically. Device according to claim 1 or 2, characterized in that the measuring device is designed to be self-adjusting. Device according to claim 1 or 2, characterized in that the measuring device works fully automatically and independently calibrated by signal processing algorithms. Device according to claim 1 or 2, characterized in that the measuring device can be used on sheet-processing machines that print on the sheet and / or subject to these other processing steps. Device according to claim 1 or 2 characterized. that the measuring device can be retrofitted to said machines. Device according to claim 1 or 2, characterized in that the measuring device by redundant information and / or signal processing, recursive algorithms is highly accurate and eliminates influences of inaccuracies of the mechanically individually executed units. Device according to claim 1 or 2, characterized in that the measuring device by evaluating the clock roller height signals all for further signal processing relevant information - in particular the machine angle information - can determine. Device according to claim 1 or 2, characterized in that the measuring device can automatically adapt to substrate thickness changes.

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