DE102010060408A1 - Arrangement for controlling web tension of e.g. paper web transported by ink printing device for multi-color printing of print material, has motors driving rollers so that web tension corresponds to web tension-reference value at inlet - Google Patents

Abstract

The arrangement has drive units (AA1-AA4) producing a correction value for a rotational speed-reference value from the rotational speed-reference value, a web tension-reference value and a web tension-actual value. The rotational speed-reference value is changed around the correction value to a corrected rotational speed-reference value for drive rollers (AT1-AT4). The corrected rotational speed-reference value is applied to drive motors (M1-M3), which drive the rollers so that a web tension corresponds to the web tension-reference value at an inlet of a reprint zone (UZ2).

Description

For single or multi-color printing of a substrate z. As a single sheet or a tape-shaped recording medium made of various materials, eg. As a paper web, ink printing devices can be used. The construction of such ink jet printing devices is known, see eg. EP 0 788 882 B1 , Inkjet printing devices, the z. B. according to the drop-on demand (DoD) principle, have as a printing unit, a printhead or more printheads with ink ducts comprising nozzles whose activators controlled by a printer control ink droplets in the direction of the substrate, which are directed to the substrate to there Apply pressure points for a printed image. The activators can generate ink droplets thermally (bubble jet) or piezoelectrically.

The printing of the print image on a printing material web is effected by a printing unit in a transfer printing zone. If a substrate web is to be printed on both sides, a printing unit must be arranged on both sides of the substrate web or the substrate web must be turned between the printing units.

For a full color printer with locally extended transfer zones, each consisting of z. B. from several spatially separated transfer printing zones in a twin printing device, the transport of the printing material must be carried out so that the speed at each location within the transfer printing zones is as equal as possible and the transport of the printing material follows a predetermined velocity profile. Furthermore, the substrate web is sufficient to tension, to ensure trouble-free transport of the printing substrate (in components such as rotating frame, cleaning, turning unit, etc.), a stable edge of the printing substrate and a flat substrate web in the transfer zones.

• – mit variabler Geschwindigkeit der Bedruckstoffbahn (z. B. bei Anpassung an die Peripherie-Performance);
• – in der Phase von Geschwindigkeitsänderungen der Bedruckstoffbahn;
• – nahtlos und ohne Anfall von Makulatur über einen Stillstand der Bedruckstoffbahn hinweg;
• – bei stark unterschiedlichen Eigenschaften der zu bedruckenden Bedruckstoffbahn;
• – bei Einwirken von Störgrößen wie Änderung des Feuchtigkeitsgehalts der Bedruckstoffbahn, Reibkräfte an der Bedruckstoffbahn, auf die Bedruckstoffbahn wirkende Massenträgheiten, Durchmesserabweichungen von Walzen

erfolgen soll.Special requirements arise when the printing of the substrate web, especially in color printing,

• - with variable speed of the substrate web (eg when adapting to the peripheral performance);
• In the phase of changes in the speed of the printing material web;
• - seamlessly and without wasting waste over a standstill of the substrate web away;
• - With very different properties of the printing substrate to be printed;
• - In the presence of disturbances such as changes in the moisture content of the printing substrate, frictional forces on the substrate web, acting on the substrate web inertias, diameter deviations of rolls

should be done.

• – durch örtlich unterschiedliche Dehnungen der Bedruckstoffbahn;
• – durch zeitlich unterschiedliche Dehnungen (Dehnungsänderungen);
• – durch deren Kombination.

Different speeds occur at different locations of the transport path of the printing material through the printing device

• - By locally different strains of the printing substrate;
• - by temporally different strains (strain changes);
• - by their combination.

Significant influences on the stretching of the printing material web are the moisture content of the printing material web and the web tension that prevails in the printing material web, as well as the mechanical properties of the printing material web.

Arrangements with which the speed of a printing material web in a device, for. As a pressure device to be kept constant, are known.

Out US 4,369,906 It is known to measure the web tension in the printing material web and adjust the angular velocity of the drive roller for the printing material web as a function of the measurement result. To measure the web tension, the printing material web is passed over a roller whose position is scanned.

EP 0 561 884 B1 describes a method for calculating and controlling the extension of a moving band. The changes in length of a reference length of the tape are measured at different tape tensions produced by a drive roller operated at different surface speeds. The measurement results can then be used to control the drive roller for the belt in printing operation so that the target voltage is set in the belt.

US 4,852,785 describes the control of a drive motor for a supply roll for a printing material web. The drive motor of the supply roll is controlled so that the belt tension remains constant even with changing diameter of the supply roll. Disclosed is a printing device that prints on both sides of the substrate web.

The problem to be solved by the invention is to specify an arrangement for controlling the web tension of a printing material web transported by a printing device, by which the influence of time-varying expansions of the printing material web (elongation changes) or of locally and temporally varying strains due to frictional forces on the Substrate web and due to acting on the substrate web inertias in the Reprint zones on the web of the substrate web is minimized.

This problem is solved by an arrangement according to the features of claim 1.

In the arrangement for controlling the web of a substrate web at a printing device in which at least one printing unit is provided which generates a printed image in a transfer zone on the substrate web, in each case a drive unit is provided with a drive roller for the printing material before and behind the transfer zone. At the drive units is the target value of the speed (speed setpoint) for the respective drive rollers. Seen in front of the transfer printing zone in the transport direction of the printing material web, a web tension measuring device is arranged which emits a web tension measured value (web tension actual value) which is dependent on the web tension. The web tension actual value is fed to a drive unit arranged adjacent to the transfer zone, which generates a corrected target value for the rotational speed (corrected rotational speed target value) of the drive roller from the web tension actual value, the rotational speed target value and a target value of the web tension. The drive unit uses the corrected speed setpoint to control the drive roller so that the web tension at the entrance of the transfer printing zone corresponds to the web tension setpoint.

Further developments of the invention will become apparent from the dependent claims.

• – Es wird ein stabiler Lauf der Bedruckstoffbahn erreicht mit minimierten Dehnungsschwankungen bezüglich des Bahnzugs, auch bei unterschiedlichen Sorten von Bedruckstoffbahnen.
• – Es kann mit veränderlicher Geschwindigkeit gedruckt werden.
• – Ein Lauf der Bedruckstoffbahn mit Reibelementen kann realisiert werden.
• – Der Bahnzug der Bedruckstoffbahn wird am Ort des Umdrucks geregelt.
• – Die Anordnung kann als Twin-Druckgerät betrieben werden, aber auch als zwei Single-Druckgeräte.

The device according to the invention thus has the following advantages:

• - A stable run of the substrate web is achieved with minimized strain variations with respect to the web tension, even with different types of printing material webs.
• - It can be printed at variable speed.
• - A run of the printing material web with friction elements can be realized.
• - The web draw of the printing material web is regulated at the location of the transfer printing.
• - The arrangement can be operated as a twin-pressure device, but also as two single-pressure devices.

With reference to an embodiment, which is illustrated in the figures, the invention will be further explained.

Show it:

1 a schematic representation of the transport path of the printing substrate by a printing device with two printing units;

2 a control circuit for controlling the drive rollers for the printing material web.

1 to illustrate the invention, the transport path of a printing material MB by a printing device, the z. B. two ink printing DW1, DW2 has. Shown is only the transport path of the printing substrate MB and the printing units DW only Umdruckzonen UZ, in which the printing on the printing material MB takes place, and drive units AA for the drive rollers AT. The drive units AA each have a drive control unit AR, a drive motor M and the drive roller AT. On the drive roller AT may possibly rest a pressure roller.

• – Im Bahnabschnitt 01 ist die Abwickelvorrichtung AW für eine Vorratsrolle für die Bedruckstoffbahn MB angeordnet, die der Antriebseinheit AA1 zugeführt wird. Die Zuführung der Bedruckstoffbahn MB zur Antriebseinheit AA1 erfolgt mit konstantem Bahnzug und mit konstanter Dehnung der Bedruckstoffbahn MB. Die Abwickelvorrichtung AW muss nicht in das Druckgerät integriert sein.
• – Im Bahnabschnitt 12 ist zwischen den Antriebseinheiten AA1 und AA2 eine Umdruckzone UZ1 angeordnet sowie eine Trocknungseinheit TR für die Bedruckstoffbahn MB. Die Antriebseinheit AA1 übernimmt mit der Antriebswalze AT1 die Bedruckstoffbahn MB von der Abwickelvorrichtung AW und treibt die Bedruckstoffbahn MB an. Von der Antriebswalze AT1 wird die Bedruckstoffbahn MB z. B. über Umlenkrollen der Umdruckzone UZ1 zugeführt, in der das Bedrucken der Bedruckstoffbahn MB erfolgt. Nach dem Umdruck wird die Bedruckstoffbahn MB durch die Trocknungseinheit TR1 geführt bevor die Bedruckstoffbahn MB der Antriebseinheit AA2 zugeführt wird, die mit der Antriebswalze AT2 die Bedruckstoffbahn MB übernimmt. Vor der Umdruckzone UZ1 kann ein Bahnzugsmessgerät BZ1 angeordnet werden, das den Bahnzug-Istwert F_ist1 misst bevor die Bedruckstoffbahn MB in die Umdruckzone UZ1 geführt wird. In der Trocknungseinheit TR1 wird die Bedruckstoffbahn MB mit Reibung beaufschlagt, z. B. über Reibflächen geführt.
• – In Bahnabschnitt 23 ist zwischen den Antriebseinheiten AA2 und AA3 eine Wendeeinheit WE für die Bedruckstoffbahn MB angeordnet. Zudem kann am Ausgang der Wendeinheit WE ein weiteres Bahnzugsmessgerät BZ2 angeordnet werden, das den Bahnzugs-Istwert F_ist2 an dieser Stelle misst.
• – In Bahnabschnitt 34 liegt zwischen den Antriebseinheiten AA3 und AA4 eine zweite Umdruckzone UZ2 für das zweite Druckwerk DW2. Am Eingang der Umdruckzone UZ2 ist ein drittes Bahnzugsmessgerät BZ3 angeordnet, das den Bahnzug-Istwert F_ist3 an dieser Stelle ermittelt; am Ausgang der Undruckzone UZ2 ist wieder eine Trocknungseinheit TR2 für die Bedruckstoffbahn MB vorgesehen. Von der Antriebseinheit AA4 kann die Bedruckstoffbahn MB mit oder ohne Bahnzug über eine Ausgabeschnittstelle AS an Nachverarbeitungsgeräte für die Bedruckstoffbahn MB übergeben werden.

For explanation, the transport path of the printing substrate MB is divided into web sections.

• In the web section 01, the unwinding device AW is arranged for a supply roll for the printing material web MB, which is supplied to the drive unit AA1. The feeding of the printing material web MB to the drive unit AA1 takes place with constant web tension and with constant stretching of the printing material web MB. The unwind AW need not be integrated into the printing device.
• In the web section 12, a transfer printing zone UZ1 is arranged between the drive units AA1 and AA2 and a drying unit TR for the printing material web MB. The drive unit AA1 takes over the printing material web MB from the unwinding device AW with the drive roller AT1 and drives the printing material web MB. From the drive roller AT1 the printing material MB z. B. via deflection rollers of the transfer zone UZ1 supplied in which the printing of the printing material MB takes place. After transfer printing, the printing material web MB is passed through the drying unit TR1 before the printing material web MB is fed to the drive unit AA2, which takes over the printing substrate web MB with the drive roller AT2. In front of the transfer printing zone UZ1, a web tension measuring device BZ1 can be arranged which measures the web tension actual value F _ist1 before the printing material web MB is guided into the transfer printing zone UZ1. In the drying unit TR1, the printing material web MB is subjected to friction, z. B. guided over friction surfaces.
• - In web section 23, a turning unit WE for the printing material web MB is arranged between the drive units AA2 and AA3. In addition, at the exit of the turning unit WE another Bahnzugsmessgerät BZ2 can be arranged, which measures the actual web tension value F _ist2 at this point.
• - In web section 34 is located between the drive units AA3 and AA4 a second transfer zone UZ2 for the second printing unit DW2. At the entrance of the transfer zone UZ2 a third Bahnzugsmessgerät BZ3 is arranged, which is the _Web tension actual value F _{ist3 determined} at this point; At the exit of the pressure zone UZ2 again a drying unit TR2 is provided for the printing material web MB. From the drive unit AA4, the printing material web MB can be transferred with or without web draw via an output interface AS to post-processing equipment for the printing material MB.

The drive units AA are now controlled such that, at least through the transfer pressure zones UZ. constant train exists. For the rule arrangement is after 2 intended. This has per drive unit AA on a drive control unit AR for the drive motor M.

The drive control unit AR2 is supplied with a speed setpoint SDAA2 for the drive motor M2, the drive control units AR1, AR3, AR4 become adjacent to the speed setpoint. SDAA2 each a web tension setpoint F _soll supplied. For these nominal values and the actual values of web _tension-F of the web tension measurement devices BZ calculate the drive control units AR1, AR3, AR4, the rotational speed for each drive motor M1, M3, M4. The setpoint values SDAA2 and F _soll are supplied by a device controller GS1 and can be selected.

In the embodiment of 2 the drive unit AA2 is used as a master unit. Thus, their drive control unit AR2 is supplied only the speed setpoint SDAA2 from the device controller GS1. In the drive control unit AR2, the speed setpoint SDAA2 is then compared with the actual speed value IDAA2 from the drive motor M2 in a control unit RE2, and the actual speed value IDAA2 is adjusted to the speed setpoint SDAA2 in the event of inequality. With the speed setpoint SDAA2, the drive roller AT2 of the drive unit AA2 is then operated, the drive roller AT2 pulls the printing material web MB with the target rotational speed SDAA2 via the drying unit TR1 and delivers the printing material web MB to the turning unit WE with the rotational speed SDAA2.

To the influence of Bahnzugsänderungen within the track section 12, z. B. by friction in the drying unit TR1 or by moisture through the print image in the transfer zone UZ1 to minimize, is not only the speed setpoint SDAA2 and the web tension setpoint F _soll12 of the device control GS1, but also the measured value of the web tension measuring device BZ1, and thus the actual web tension value F _ist1 at the entrance of the transfer pressure zone UZ1, included in the control of the drive motor M1. In the drive control unit AR1 therefore two control units RE1 and RE2 are provided. With the first control unit RE1 the web tension actual value F _IST1 is compared with the web tension set point F _soll12, and generates a correction value OS1 in response to the difference by which the speed reference SDAA2 is corrected to the corrected speed command SDAA1, of the second Control unit RE2 is supplied. The second control unit RE2 then controls the speed of the drive motor M1 to the corrected target speed SDAA1. Web tension changes due to changes in length of the printing material web MB are thus minimized via the drive unit AA1, which reduces or increases the rotational speed of the drive roller AT1 with respect to the target rotational speed SDAA2.

When arranged at the output of the turning unit WE drive unit AA3 the speed setpoint SDAA2 is changed by a correction value OS3, the supplied from the ascertained by the web tension meter BZ2 web tension actual value F _ist2 and the web tension set point F _soll23 depends on the device control GS1. The first control unit RE1 determines from the web tension setpoint F _soll23 and the web tension actual value F _ist2 from the web tension measuring device BZ2 the correction value OS3 by which the speed setpoint SDAA2 is corrected to the speed setpoint SDAA3. By the second control unit RE2, the speed IDAA3 of the drive motor M3 is controlled to the corrected speed setpoint SDAA3. The speed of the drive roller AT3 is then adjusted so that the printing material web MB is supplied with the desired web of the Umdruckzone UZ2. The strain changes of the printing MB caused by the turning unit WE are thus corrected using the signal supplied by the arranged after the turning unit WE web tension meter BZ2 actual value of the web tension F _ist2.

An operating mode corresponding to the drive unit AA1 is provided for the drive unit AA4. To the influence of Bahnzugsänderungen within the track section 34, z. B. by friction in the drying unit TR2 or moisture through the printed image in the transfer zone UZ2 to minimize, in the drive control unit AR4 next to the speed setpoint SDAA2 and the actual train value F _ist3 of the web tension meter BZ3, and thus the actual train F _ist3 at the entrance of the transfer zone UZ2, and the web tension setpoint F _{soll34 included} in the control of the drive motor M4. In turn, two control units RE1, RE2 are provided in the drive control unit AR4. With the first control unit RE1, the actual web tension F _ist3 for the web tension is compared with the web tension setpoint F _soll34 delivered by the device control GS1, and a correction value OSF4 is generated as a function of the difference. This correction value OSF4 is supplemented by the correction value OS3 of the drive control unit AR3 and used as a correction value OS4 to correct the target speed SDAA2 to the target speed SDAA4 before this second control unit RE2 is supplied. The second control unit RE2 then controls the actual speed value IDAA4 of the drive motor M4 to the corrected speed setpoint SDAA4. Web tension changes caused by changes in length of the printing material MB are thus minimized via the drive unit AA4, to the speed of the drive roller AT4 is reduced or increased compared to the target speed SDAA2.

In the exemplary embodiment, the drive roller AT2 is selected as the master drive roller; in twin operation, it receives its speed setpoint SDAA2 from the device control GS1. The speed setpoint SDAA2 is also fed via a bus system BS to the other drive units AA1, AA3, AA4. In the exemplary embodiment, the master drive unit AA2 is the first drive unit downstream of the transfer printing zone UZ1. As a result, a decoupling of the transfer printing zone UZ1 from the friction surfaces in the turning unit WE and the friction surfaces in the drying unit TR1 is achieved when stopping the printing material web MB, which lead to high changes of the web tension by movement of the drive roller AT2 in the compensation processes (moisture change in the printing material MB) would. The further drive rollers AT1, AT3, AT4 are speed controlled via the drive control units AR1, AR3, AR4 and follow with their speed the speed setpoint SDAA2, which is respectively corrected by the correction value OS (offset)

The following applies: SDAAi _should = SDAsoll + OSi with i = 3, 4. SDAAi _should = SDA _should - OSi with i = 1.

In the case of the drive control unit AR1, the correction value OS1 thus runs counter to those in the drive control units AR3, AR4 given equal control deviations of the web tension.

The speed setpoint SDAA2 is transmitted by the bus system BS continuously and at a high transmission rate to the drive units AA1, AA3, AA4, so that the drive rollers AT1, AT3, AT4 can rapidly follow the speed setpoint SDAA2 supplied to the drive roller AT2. By controlling the drive rollers AT after the speed setpoint SDAA2 is achieved that all drive rollers AT with the same speed changes and thus move uniformly.

• – In den Bahnabschnitten 12, 34, die eine Umdruckzone UZ enthalten, nahe dem Eingang der Umdruckzone UZ; dadurch wird die Umdruckzone UZ von Reibkräften der Reibflächen in den Trocknungseinheiten TR, Umlenkungen der Bedruckstoffbahn MB gekennzeichnet durch den Buchstaben U zwischen den Umdruckzonen UZ und den Antriebswalzen AT entkoppelt.
• – In dem Bahnabschnitt 23 ohne Umdruckzone nahe der zu regelnden Antriebswalze AT3, um eine konstante Dehnung der Bedruckstoffbahn MB am Eingang für den nächsten Bahnabschnitt 34 zu gewährleisten.

The drive rollers AT1, AT3, AT4 are now controlled so that the web tension in the printing material MB even with the occurrence of disturbances such. B. moisture change, friction surfaces, diameter deviations, exposure to inertia, remains constant. This is achieved by the arrangement of the web tension measuring devices BZ in the transport path of the printing material web MB. For this purpose, a web tension measuring device BZ is arranged in each case:

• - In the web sections 12, 34, which contain a transfer zone UZ, near the entrance of the transfer zone UZ; As a result, the transfer printing zone UZ is decoupled from frictional forces of the friction surfaces in the drying units TR, deflections of the printing substrate web M characterized by the letter U between the transfer printing zones UZ and the drive rollers AT.
• In the web section 23 without transfer printing zone near the drive roller AT3 to be controlled in order to ensure a constant stretching of the printing material web MB at the entrance to the next web section 34.

The measured web tension F _is fed to the drive control units AR1, AR4 per path section, which compares this in the first control unit RE1 with a predetermined web tension setpoint F _soll and determines from the comparison result the correction value OS for the speed setpoint SDAA2, from which the corrected speed -Sollwert SDAAi for the second control unit RE2 is obtained. In the determination of the corrected speed setpoint SDAA4, however, in addition to the correction value OSF4 of the control unit RE1 of the drive control unit AR4 also the correction signal OS3 is taken into account by the drive control unit AR3 to achieve synchronization between drive control units AR3 and AR4.

Due to the arrangement of the web tension measuring devices BZ close to the transfer printing zones UZ, a uniform web tension and a uniform elongation are achieved there. In this case, the web tension can _be regulated in each path section to a predetermined value F _soll .

When the printing material web MB stops, the control arrangement ensures that a defined and equally high web tension is maintained in the transfer printing zones UZ. Furthermore, the web sections are kept long with Umdruckzone UZ, so that disturbances on the elongation of the printing material MB impact only with a long time constant, the strain change in the printing material MB runs slowly.

For the start, stop and other speed changes, the drive units AR have been synchronized so that the rotational speeds of the drive rollers AT move uniformly and without a time offset. Thus, the train remains constant even in these speed phases.

To the bus system BS more drive units AR can be connected, z. B. enough drive rollers AT for the operation of two Transfer printing zones UZ for printing on the front side and the back side of the printing material web MB. However, the bus system BS can also be separated, z. B. at the separation point TS to create two independently operable pressure equipment. In this case, the drive unit AR4 receives the speed setpoint from a device controller GS2. The actual web tension value measured by the web tension measuring device BZ3 is then supplied to the drive unit AR3.

• – die Dehnung des stromaufwärts liegenden Bahnabschnitts konstant gehalten wird;
• – sich die Antriebswalzen AT zu Beginn und Ende eines Bahnabschnitts zu jedem Zeitabschnitt gleichförmig, d. h. mit denselben Geschwindigkeitsänderungen über die Zeit bewegen;
• – die Zeitkonstante für die Dehnungsänderungen möglichst groß ist aufgrund einer großen Bahnabschnittslänge.

By the control arrangement according to the invention it is achieved that

• - The elongation of the upstream track section is kept constant;
• - The drive rollers AT at the beginning and end of a track section at each time period uniformly, ie move with the same speed changes over time;
• - The time constant for the strain changes is as large as possible due to a large track section length.

The web tension measuring devices BZ, which allow the regulation of the constant strain, are arranged close to the transfer pressure zones UZ. Thus, disturbances such. B. frictional forces and inertia in the pressure zones UZ not from.

The control of the drive rollers AT is also designed so that the web tension over the entire speed spectrum remains sufficiently high. The expansion changes due to the moisture content of the printing material web MB is compensated by the web tension control. The control arrangement is realized so that even with a stop of the printing material MB of the web train is kept constant.

The components used in the control arrangement such as control units RE or Bahnzugmessgerät BZ are of known construction. As control units RE can z. B. PI controller can be used.

Known web tension measuring devices BZ supply z. B. an analog current signal which is proportional to the web tension in the printing material MB. The analogue signal is converted in an analogue to digital converter into a digital value F _ist , which corresponds to the web tension. The actual values F _are the web tension measurements are compared with the setpoints F _soll , which can also be present as digital values. The two F values are processed in a digital PI controller RE1. The PI controller RE1 requires as parameters a gain factor and a reset time. These parameters are determined according to stability criteria (once in advance) and stored in the drive control units AR, depending on the actual rotating field frequency of the drive motor M. The parameters may be different for each drive control unit AR.

The output value of the PI controller RE1 is the correction value OS (a digital value that can be greater than or less than or equal to 0) whose dimension is z. B. is a rotating field frequency in Hz. The correction value OS is added or subtracted to the speed setpoint SDAA2 (which can have the dimension rotating field frequency in Hz as the digital value). The actual speed value IDAA2 corresponds to the rotating field frequency of the motor M and can be a digital value with the dimension Hz.

The second PI controller RE2 is a digital speed controller and processes the actual speed value IDAA2 and the one around the. Correction value OS corrected speed setpoint SDAA.

The invention is in connection with an ink printing device. been described. However, the control arrangement can be used in other printing devices in which the web tension is to be kept constant by the printing unit.

LIST OF REFERENCE NUMBERS

• BS

  bus system

  AA

  drive unit

  AR

  Drive control unit

  AT

  drive roller

  RE

  control unit

  M

  drive motor

  UZ

  transfer printing

  TR

  drying unit

  U

  deflecting

  WE

  turning unit

  GS

  device control

  MB

  printing material

  BZ

  Tension meter

  AW

  unwinding

  AS

  Device of post-processing

  TS

  separation point

  SD

  rotation speed

  F

  Train

  OS

  Correction value = Offset

  DW

  printing unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0788882 B1 [0001]
• US 4369906 [0008]
• EP 0561884 B1 [0009]
• US 4852785 [0010]

Claims (10)

Arrangement for controlling the web of a substrate web at a printing device, - in which at least one printing unit (DW) is provided which generates a printed image in a transfer zone (UZ) on the printing material (MB), - in front of and behind the transfer zone (UZ A drive unit (AA) with a drive roller (AT) for the printing material web (MB) is arranged, in each case one of a device control (GS1) supplied speed setpoint (SDAA _soll ) for the Drive roller (AT) is applied, - in which in front of the transfer zone (UZ) a web tension measuring device (BZ) is arranged which emits a train of the printing material (MB) dependent web train actual value (F _ist ), which at one of the drive units (AA) is applied, said drive unit (AA) from the speed setpoint (SDAA _soll), supplied from one of the device control (GS1) web tension reference value (F _desired) and the web tension actual value _(F) a correction value (OS) for the speed setpoint (SDAA _soll) produced by which the speed setpoint (SDAA _soll) to a corrected speed reference value (SDAA) for the drive roll (AT) is changed, and the corrected speed reference value (SDAA ) to a drive motor (M) for the drive roller (AT) is applied, which drives the drive roller (AT) so that the web of the printing material web (MB) at the entrance of the transfer zone (UZ) corresponds to the web tension setpoint (F _soll ). Arrangement according to Claim 1, in which the speed set value (SDAA _soll = SDAA2) is applied to the drive unit (AA2) behind the first transfer pressure zone (UZ1) in a first printing unit (DW1) and the drive unit (AA2) controls the speed of the associated drive roller (AA2). AT2) to the speed setpoint (SDAA2), in which before the first transfer zone (UZ1) a web tension measuring device (BZ1) is arranged, which outputs a train of the printing material (MB) dependent web train actual value (F _ist1 ) at the on the drive unit (AA1) before the first Umdruckzone (UZ1) of the speed setpoint (SDAA2), the Bahnzugs setpoint (F _soll12 ) and the web tension actual value (F _ist1 ) is applied, said drive unit (AA1) the speed of their drive roller ( AT1) controls such that at the entrance of the first transfer printing zone (UZ1) the printing material web (MB) has the web tension setpoint (F _soll2 ). Arrangement according to Claim 2, in which the printing apparatus has two printing units (DW1, DW2), in which the second printing unit (DW2) with two drive units (AA3, AM) and behind the first printing unit (DW1) in the transport direction of the printing material web (MB) a second transfer printing zone (UZ2) between the drive units (AA3, AA4) is arranged, in front of the second transfer zone (UZ2) a second web tension measuring device (BZ3) is arranged, the actual web tension value (F _ist3 ) one of the drive units (AA4) for Control whose drive roller (AT4) is supplied. Arrangement according to claim 3, in which a turning unit (WE) for the printing material web (MB) is arranged between the first printing unit (DW1) and the second printing unit (DW2), at the output of the turning unit (WE) a third web tension measuring device (BZ2) is arranged, the web tension measurement (F _ist2) of the drive unit (AA3) prior to the second transfer printing zone (UZ2) is supplied to said drive unit (AA3) from the speed setpoint (SDAA2) supplied from one of the device control (GS1) Web tension setpoint (F _soll23 ) and the web tension actual value (F _ist2 ) a correction signal (OS3) for generating a corrected speed setpoint (SDAA3) for the speed of the associated drive roller (AT3) outputs to the drive roller (AT3) so Control that the web tension at the entrance of the second transfer zone (UZ2) corresponds to the web tension setpoint (F _soll23 ). Arrangement according to Claim 4, in which the actual web tension value (F _ist3 ) from the second web tension measuring device (BZ3) is applied to the drive unit (AA4) _{downstream of} the second transfer printing zone (UZ2), this drive unit (AA4) being selected from the rotational speed desired value (SDAA2). in that a web tension set value (F _set34 ) and the web tension actual value (F _ist3 ) supplied by the device control (GS1) comprise a correction value (OSF4) for generating a corrected speed set value (SDAA4) for the speed of the associated drive roller (AT4) in order to control the drive roller (AT4) so that the web tension at the exit of the second printing unit (DW2) corresponds to the web tension setpoint (F _target34 ). Arrangement according to Claim 5, in which the correction signal (OS3) generated by the drive unit (AA3) in front of the second transfer zone (UZ2) additionally bears against the drive unit (AA4) provided after the second transfer zone (UZ2), this drive unit (AA4) consisting of the own correction value (OSF4) and the correction value (OS3) of the drive unit (AA3) before the second transfer zone (UZ2) generates the correction value (OS4) for the speed setpoint (SDAA4). Arrangement according to one of Claims 2 to 6, in which the drive unit (AA2), to which no web tension actual value (F _ist ) is present, has a drive control unit (AR2) with a control unit (RE2) which determines the rotational speed of the drive motor (M2). to the speed setpoint (SDAA2). Arrangement according to one of the preceding claims, in which the drive units (AA1, AA3, AA4) on which a web tension actual value (F _ist ) is present, a drive control unit (AR1, AR3, AR4) of a first control unit (RE1) and a second control unit (RE2) have, in which the first control unit (RE1) from the web tension measured value _(F), and that of the device controller (GS1) supplied web tension setpoint (F _set) the correction value (OS) for the speed setpoint ( SDAA2) by which the speed command value (SDAA2) supplied by the apparatus controller (GS1) is changed to the corrected speed command value (SDAA) at which the speed command value (OS) corrected by the correcting value (OS) is applied to the second control unit (RE2). SDAA) is applied, wherein the second control unit (RE2) controls the speed of the drive roller (AT1, AT3, AT4) to the corrected speed setpoint (SDAA). Arrangement according to one of the preceding claims, wherein the transport path between the drive units (AA) via the respective transfer printing zone (UZ) is designed such that the time constant for strain changes of the printing material web (MB) is large. Arrangement according to one of the preceding claims, in which the respective printing unit (DW) is an ink printing unit which generates print images on the printing material web (MB) in the transfer printing zone (UZ), in which a drying unit (TR) for the printing material web (MB) is provided between the transfer printing zone (UZ) and the drive unit (AA) at the exit of the transfer printing zone (UZ), wherein at the entrance of the transfer printing zone (UZ) adjacent to the respective drive roller (AT1, AT3) of the drive unit (AA1, AA3) a web tension measuring device (BZ1, BZ3) is arranged.

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