DE102009002755A1 - Method for ground control in ground processing machine, particularly sheet-fed letterpress rotary, involves continuous scanning of height profile of sheet sequence and continuous processing of detected profile height - Google Patents

Abstract

The method involves continuous scanning of the height profile of the sheet sequence and continuous processing of the detected profile height. A target-average value is formed by a machine cycle upholster measuring interval from the continuously measured profile height of error-free sheet sequence. The target-average value is calculated from sheet thickness, format length and sheet distance. An independent claim is also included for a scanning device for the execution of the method.

Description

The The invention relates to a method and a scanner for sheet control in a sheet-processing machine, in particular sheet-fed rotary printing press, wherein the sheets to be processed machine cycles in a sequence of sheets supplied with constant arc distance of the machine or transported in this, the height profile of the bow sequence continuously scanned and recorded thereby profile heights be further processed.

The supervision of bow sequences with regard to the correct bow length, Arc distances and sheet layers in a curved formation, in particular at Sheet-processing machines such as sheet-fed rotary printing machines, ensures trouble-free operation of the respective sheet processing process.

In Sheet-fed rotary presses become the sheets to be printed a feeder withdrawn from a pile of investment piles and with pneumatic and mechanical means isolated on a feed table in one scaly arch formation to a Bogenzuführeinrichtung transported, aligned and then fed to the first printing unit. Thus pressure disturbances or even printing machine damages by faulty sheet separation or flaking (Bogenfolgestörungen) and thus not properly in the printing units drawn sheets (false sheets) are avoided, takes place at different Make the conveyor line a sensory monitoring the arch formation on false arch. But also at bow processing Machines where, for example, several sheets to a printed product are summarized (folding and binding machines), is a sheet formation monitoring appropriate.

Under The term false arch is intended to mean all arches in the arch formation be understood, with regard to at least one property from a properly transported bow differ. For example, a false arch may be a Double arch of two unseparated, one above the other Act bow. Will such a double sheet or even a multiple arc fed to a printing press, this can cause damage lead from printing units of the printing press. Furthermore, can a false arch is a so-called oblique arch, that is to say, a bow with an incorrect imbalance in the Sheet formation fed to the sheet feeder, thus poorly aligned and not printed on register becomes. In addition to double sheets and oblique sheets can this also missing sheet, early bow or late bow be. Missing bow and multiple bow soft as double bow in terms the number of sheets of the proper bow formation in the shingled stream. For early bow and late bow deviates as in oblique arc, the position of the arc in the scale flow from the normal position (constant arc distance). Furthermore you can too short or too long, d. H. from the proper Format deviating bow cause pressure disturbances.

Of the Term double sheet is commonly used as a synonym for all invalid multiple sheets that are incomplete were isolated, used. With a double sheet control device Accordingly, not isolated sheets are recorded, the two times, three times or in even greater numbers one above the other be conveyed in the shingled stream and after moving into the printing press pressure disturbances up to machine damages can cause. Multiple-sheet monitoring equipment are also referred to as package controls. With double or multiple sheet checks also missing sheets can be recorded.

to Double sheet control find use of control devices that the sheet formation surface non-contact or mechanically scan and thereby the distance to the sheet surface or determine the profile height of the arc sequence. For example are contactless scanning double sheet control devices known as ultrasonic or capacitive measuring devices, the the height profile of the arc sequence over a reflection or absorb absorption of transmitting radiation. Farther In practice double sheet control devices are used, which are based on the principle of optical transmission or reflection. Non-contact sheet control devices have indeed the advantage that they do not damage the sheets or affect adversely in their run, but deliver due narrow measuring range limits or a not always flat sheet position, enclosed air pockets or different sheet materials strongly faulty signals, which require complex signal processing or require fault compensation with combination sensors. Optical, capacitive or ultrasonic double-sheet control devices usually satisfied only in the presence of single sheets putting results.

In practice, therefore, mechanically working devices are used on sheet-printing or processing machines for the identification of double sheets, which mechanically scan the imprint flow to be checked of the printed sheets. In this case, a stationary mounted measuring wheel of the mechanical double sheet control device rolls on the sheet flow moving to the sheet feeding device of the printing sheet or a touch sensor is on the scale surface with a pressing force, causing the arc in the measuring area without gaps on each other and placed on the feed table and thus measurement errors are largely avoided. A mechanical sheet scanning also has the advantage that influences of the sheet material, in particular its permeability or its surface properties, can be disregarded in the measurement.

Indeed required the earlier mechanical double sheet control equipment some effort in their sheet thickness dependent adjustment.

At first microswitches were used for mechanical double sheet control, which by mechanical adjustment to a defined threshold the bowshoot thickness had to be adjusted. It had to the query time (query window) are placed in an area, where the set archery thickness actually was present. When changing the arc length (Format change) the location and size of this changed Query window.

When Further development of this system became later in place of the microswitch an analog measuring displacement sensor provided. The mechanical adjustment of the microswitch was eliminated. Of the Threshold could now easily be specified as continuously electrical value from the entered substrate data automatically to be provided.

At the Placing the sensing device on the archery surface and when "passing" an arbor heel (eg from 3 to 2 superimposed sheets) However, in mechanical double sheet control devices transient phenomena on which a threshold-based double-sheet query in these Do not allow areas. The settling time of the sensing device hangs thereby of the mechanical characteristics of the complete system from. The transient processes have been limited so far a reliable mechanical double-sheet detection thick substrate sheet.

Becomes If a double sheet is detected, the sheet system is blocked and stopping the sheet feeder. For the execution such an emergency stop is only available for a short time, before the double sheet enters the machine. It is therefore appropriate Double sheets as well as all other false sheets as early as possible to capture. That's the use of it anyway for the sheet separation existing clock roll in the first Section of the sheet transport path to the first printing unit advantageous.

From the DE 293 02 70 A1 and the DE 103 48 029 A1 are mechanical double sheet control devices with movably mounted clock rollers known, the sheets are pressed by the clock-controlled at each incoming sheet set clock role on a fixedly mounted transport roller and conveyed in frictional engagement with the transport roller between the control roller and transport roller. The clock roller is arranged on a pivotally mounted roller lever, wherein the deflection of the roller lever forms a measure of the thickness of the arbor and thus a parameter for determining and monitoring the number of übereinanderbefindlichen sheet. For the determination of the deflection of the roller lever, for example, optical or inductive distance meter are provided which detect the position of the roller lever either continuously or when exceeding limit positions actuate a switch that activates a fault signal. The sensor for the position of the roller lever must be adjusted for a reliable double or multiple sheet detection in a complex manner to the sheet thickness to be processed by the duplex feeder is manually moved in set-up by the operator in the active area of the double-sheet interrogation and depending on the number of controlled sheet layers one, two or three sheets are pushed under the control roller to set the switching threshold in excess of the intended number of superimposed sheets during the query of the double sheet control device. Furthermore, it is disadvantageous that it is necessary for the reliability of the mechanical double-sheet control device to tune the query window on the sheet sequence in the continuously scaled to launch line bow, that the spring-loaded scanning (here the clock roller) within the specified by query start and query end query window not by Arc edge passes are excited to vibrations that can trigger false alarms.

From the DE 10 2007 009 675 A1 a method for setting a double sheet control device at the feeder feeder of a sheet-fed rotary printing machine is known, with the double sheet control device a machine cycle controlled scanning of a printed material sheet formed Schuppenstromes and a fault signal is output when the double sheet control device detected within a specified query window an unacceptable number of superimposed sheet, said after one Entering or accepting the sheet length from an order data memory, an automatic setting of the query window for the double sheet control device in dependence on the arc length is done. It is expedient to adjust the double sheet control device on scale flow sections with double sheet position. After setting the double sheet control device on the Bo to be processed Gendicke is then automatically driven depending on sheet length in a required archery position. A disadvantage is the cost of the positioning of the double sheet control device.

From the DE 44 31 934 A1 and the DE 10 2004 053 891 A1 Methods and apparatus for non-contact double sheet control are known in which the problem of positioning the double sheet control device is countered by a fixed arranged continuous arcscope current scan over at least one arc length be. In the non-contact capacitive and inductive measuring devices used, the useful signals must be subjected to a complex signal processing for the elimination of interference signals.

In the DE 199 30 738 A1 an evaluation method for an optoelectronic double sheet control device is described, in which a continuous scanning signal of the arbor is compared with a stored nominal waveform and an error signal is derived in case of deviations between the actual and nominal thickness profile.

From the EP 0 556 486 A1 a continuous Schuppenstromabtastung with two coupled scan rollers is known, being determined from the measurement of the relative level of one of the measuring points with respect to the height level of the second measuring point false-arc.

Of the Invention is based on the object, a method and an apparatus while retaining the advantages of mechanical double sheet control devices Maximum detection reliability for double or multiple sheets also possible with thin printing material sheets.

According to the invention the object by a method having the features of the first claim or a device having the features of the sixth claim. The proposed solution for sheet control for detection of false sheets in a sheet-processing machine, in particular Sheet-fed rotary printing machine, wherein the sheets to be processed machine cycles fed in a sequence of sheets with a constant arc distance of the machine or transported in this, the height profile of the Arc sequence continuously sampled and recorded thereby profile heights be further processed, that includes in set up or at the beginning of the printing operation over a constant machine-cycle-related Measuring interval from the continuously measured profile heights a fault-free arc sequence a desired mean or formed this calculated from arch thickness, arc distance and format length is, in the subsequent printing operation continuously or at predetermined intervals on each whole or approximately whole machine cycles and from Sheet format independent further profile height averages be determined and exceedances of specifiable deviations of continuously determined profile height averages of the desired mean value the profile heights are counted as a false arch and a intended operation of the machine for disposal trigger the bow following fault.

to Realization of the method is preferably carried out with at least one the existing and for a profile height measurement trained clock roller or with another suitable mechanical Profile height measuring device the height profile of Arc sequence continuously sampled in cycles. From the repetitive Profile height gradients are after further processing the continuously recorded profile height measurements for whole machine cycles averages formed and for double sheet detection used.

By the formation of reference or desired mean values from the real measurement signal profile over the Total or almost entire duration of a machine cycle become transient phases the measuring device and different arc lengths in taken into account the means, so they do not lead to misinterpretations of the profile height measured values. Only during the delivery movements of the double sheet control devices the profile height signals are not evaluated. These In particular, the reliability of the method improves Double sheet control device for thin substrates.

With the mechanical measuring device is for special materials, which not by optical, capacitive or ultrasonic double-sheet controls be recognized, in the first place an effective double sheet control possible.

The proposed solution has the further advantage that with the double sheet control already at the takeaway double sheets or multiple sheets early on the feeder recognize let so that the indentation of double sheets into the sheet processing Machine can be prevented on time.

With the installation of a mechanical double sheet control device in the standard clock roller is one inexpensive and space-saving mechanical double sheet control feasible, which has no influence on the sheet travel, because the movement the clock role itself is not changed.

In the following, the invention is by way of example be explained. The accompanying drawings represent:

1 : Representation of the arcing formation of a sheet feeder with a control roller on a sheet-fed rotary printing machine

2 : Signal profile of a profile height measuring device on the control roller

Like from the 1 Obviously, the bows become 1 transported to a Schuppenanleger a Bo genrotationsdruckmaschine after subtracting from a sheet pile in imbricated formation to a (not shown) laying line. These are the bow 1 with the help of suction belts on a suction belt table 4 with constant distance of the sheet leading edges (scale length) moved forward. To realize the clocked sheet transport for the formation of the imbricated formation sets a centrally located clock role 2 or set several, transversely to the transport direction juxtaposed pivotable and freely movable clock rollers 2 Clock-controlled on the bow surfaces and each provide a temporary frictional engagement between bow 1 and suction band 3 for sheet conveying. The timing control is derived from the rotational angular position of a press machine shaft relevant to the machine control (single-speed reference shaft ETW) and serves to control the arrival of the sheet at the landing line. The clock control is known and irrelevant to the inventive solution and is therefore not explained in detail.

At least one of the clock roles 2 met in the embodiment a dual function by additionally their distance from the respective suction belt 3 which measures the profile height of the archer formation in the scanning gap between the inspection roller 2 and suction band 3 is detected and monitored by a double sheet control device. This is for example the location of a roller lever on which the clock roller 2 Usually stored, monitored by a continuously measuring distance sensor. The padded clock roller 2 is excited during the run on the traversing arches formation when entering sheet leading edges to vibrations that flow into the averaging. The clock role 2 scans sheet layers with single, double or triple sheet position, depending on sheet size and scale length. The determination of the profile height or the further processing of the resulting profile height signals can be carried out continuously during the printing operation or at predeterminable intervals.

The evaluation of the profile height signal is carried out according to the invention as follows:
Known manner are in the undisturbed arbor formation 1, 2 or 3 sheets with a constant leading edge distance staggered one above the other. The number of overlapping sheets 1 and the resulting height profile of the archery formation in the measuring interval is dependent on the format length and the sheet spacing in the sheet conveying direction. For a constant arc length, this results in a cyclically repeating profile height curve for each print job over 360 ° of the machine cycle predetermining single-turn shaft. The length and location of the measuring interval is no longer dependent on the format length in the proposed solution, but only on the machine cycle.

In set-up mode or at the beginning of printing at the beginning of sheet feeding, the simple sheet thickness will always be available as the mean value in the first bar. This is used to control the function of the profile height measuring device of the control roller 2 compared with the theoretical substrate thickness value entered or taken from the order data. For the one or two cycles following the first cycle, a desired mean value is calculated from the real substrate thickness measured in the first cycle and the sheet format length. From the measured in the first cycle real substrate thickness and the format length can be calculated at a predetermined arc distance instead of a profile height measurement, first, a desired average for the profile height.

In the continuous printing operation, the constant clock-related measuring intervals are now used continuously from the control roller 2 detected profile height values clock-related, ie formed over each entire machine cycles, averages determined. The length of the measurement intervals extends over the periods in which the clock role 2 during the machine cycle. is placed on the arbor formation. For continuously scanning double-sheet control devices, the average values are determined over the entire machine cycle. The mean values of the measured profile heights of the undisturbed arcing formation over the measuring intervals (nominal value) depend on the sheet thickness, the sheet spacing and the format length and can be specified as a factor for the substrate thickness as a function of the format length.

A false sheet is recognizable at a mean profile height exceeding or exceeding the nominal mean value of the profile height beyond a tolerance dimension. For example, a double sheet is present if, due to insufficient singulation, two or more sheets instead of the expected single sheet 1 lie on top of each other or instead of a double sheet layer at least three sheets 1 lie over each other, etc.

A double bow passes the control 2 , the mean value will be larger by the amount (factor x substrate thickness) than in the undisturbed sheet formation. On the other hand, in the case of a missing sheet, the mean value will be reduced by this amount. At least those deviations from the nominal mean value, which reach or exceed the simple sheet thickness multiplied by the ratio of the arc length to the arc spacing, are thus evaluated as false bends. When the clock roll 2 in each machine cycle touches only in the interval in which no Bogenvorder- or trailing edges go through, the bow control designed particularly simple, since the profile height averages are then an integer multiple of the sheet thickness and deviations from approximately the sheet thickness are an indicator of false bows.

• – Temperaturdrift in Mechanik und Sensor
• – Veränderung der Rollengummieinfederung an der Taktrolle 2 bei Drehzahlvariation (Dynamische Eigenschaften des Rollengummis)

In continuous printing, each average determined with the scanning device is not only used for false-sheet detection, but also compared with the initially determined reference or desired mean value, which is formed from a previous measured value or from the mean value of a group of preceding measured values of fault-free sheet sequences. The reference or desired mean value is continuously updated in this way with current averages. By this method, different drift phenomena are compensated, whereby the reliable double-sheet detection by means of a control roller 2 only possible with thin materials. Typical drifting phenomena are:

• - Temperature drift in mechanics and sensor
• - Change the Rollengummieinseddingerung on the control roller 2 at speed variation (dynamic properties of the roller rubber)

In the example of 2 are the mean profile heights in the measuring intervals of the control roller 2 approx. 200 μm. There is a fault-free or false-arch-free archery formation. From 90 ° ETW, an extra sheet (false or double sheet) is under the control 2 , This shows up in the jump of the average value for the previous measurement interval 90 ° -340 ° ETW at 340 ° ETW by the amount of the sheet thickness of about 50 microns, whereupon the press controller a predetermined double sheet routine to eliminate the sheet disturbance is triggered, for example, an interruption the sheet feed to the machine (investment stopper) involves the non-separated sheets 1 to be able to remove from the arch formation. From the location of the measuring cycles (clock blocks in the upper part of the 2 ) it can be seen that the clock role 2 not during the entire duration of a machine cycle (each 360 ° ETW) on the sheet formation touches down. The discontinuities in the height signal of the clock role 2 in the right sections of the measuring intervals, the spring-loaded control roller becomes traversed by continuous sheet edges and associated transient processes 2 caused. The transient phases can - as in the embodiment - be included in the proposed control method in the averaging and therefore advantageously do not interfere with the accuracy of the measurement method as a disturbance.

The device for carrying out the method is based on a sheet-fed rotary printing machine with a programmable machine control, which is equipped with a double-sheet monitoring device that measures continuously in cycles, in particular at least one control roller 2 with profile height measuring device connected. According to the invention, the machine controller contains a program module for averaging the profile height values continuously acquired during the machine cycles, for comparison with previously determined setpoint values and depending on the comparison result for outputting control commands at least for stopping the investor to eliminate the sheet running disturbance. In contrast to known double sheet control methods, the archery profile is not only scanned during certain, closely spaced sheet length and arc spacing-dependent intervals, but it is intermittently for the entire period in which the clock role 2 is set during a measure, profile height averages for the measurement interval determined. As a result, the archery profile scan is virtually continuous and independent of the sheet format. This is a substantial simplification of the double-sheet control process by the elimination of the sheet format-dependent adjustment of the double sheet control device is connected.

In particular for detecting oblique sheets, the height profile of the sheet sequence can be parallel to a plurality of clock rollers arranged transversely to the direction of sheet travel 2 be sampled, wherein mean differences between the arranged at the same height clock roles 2 be evaluated.

The proposed method is also advantageous with separate Taktrollen or other mechanical feelers or else with non-contact scanning devices for double sheet control applicable. Likewise, other measuring locations than the sheet system described a sheet-fed rotary printing press possible because the measuring method only the presence of a regularly is bound to repeating arch formation.

1

bow

2

synchronizing roller

3

suction belt

4

feed table

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 2930270 A1 [0013]
• - DE 10348029 A1 [0013]
• DE 102007009675 A1 [0014]
• - DE 4431934 A1 [0015]
• - DE 102004053891 A1 [0015]
• - DE 19930738 A1 [0016]
• EP 0556486 A1 [0017]

Claims (6)

Method for sheet control in a sheet ( 1 ) processing machine, in particular sheet-fed rotary printing machine, wherein the sheets to be processed ( 1 ) - fed to the machine in a sequence of sheets with a constant arc distance or transported in this, - continuously scanned the height profile of the sheet sequence and - the recorded profile heights further processed, characterized in that - over a machine cycle-related measurement interval from the continuously measured profile heights of a faultless Arc sequence a desired mean value is formed or this is calculated from sheet thickness, format length and arc distance, - during profile printing over each entire machine cycle further profile height averages are determined, - Exceeding of predetermined deviations of the further determined profile height averages from the desired average value of the profile height one Start operating mode of the machine to eliminate arc following faults. Method according to claim 1, characterized in that that at least those deviations as Bogenfolgestörung the profile height averages are taken with the the ratio of the arc length to the arc distance Reaching or exceeding the multiplied simple arc thickness. Method according to claim 1, characterized in that that the simple arch thickness is preferably at the beginning of the printing operation measured or taken from the order data. Method according to claim 1, characterized in that that the continuously determined profile height averages with previous profile height averages error-free Arc sequences compared and the continuously determined profile height averages be used for drift compensation. Method according to claim 1, characterized in that that in particular for the detection of slanted the height profile the arc sequence arranged in parallel at several transversely to the sheet running direction Sensing devices is scanned. Sensing device for carrying out the method according to claim 1, characterized in that the sensing device - at least one control roller ( 2 ) a sheet feeder of a sheet-fed rotary printing press with profile height measuring device or another intermittent recording the profile height detecting and - a processing device for profile height signals, the intermittently over the entire period in which the clock role ( 2 ) is set up during a cycle, determines profile height averages for the measuring interval and, in the event of deviations from the setpoint, outputs control signals to the machine control for triggering the mode of operation of the machine intended for false bends.