EP1252018B1 - Method for adjustment of a belt tension in a rotary press machine - Google Patents

Abstract

The tension of a web in a rotary printing machine is monitored and adjusted. The web runs through at least one printing group in the rotary printing machine. Any change in the stretch of the web during the production run is determined by noting any difference between first and second speeds of the web. The change in stretch is compensated for by a change in the tension of the web before the first printing group.

Description

The invention relates to a method for regulating a web tension in a Rotary printing machine according to the preamble of claim 1.

EP 09 51 993 A1 is a register drive for one Rotary printing machine is known, wherein a longitudinal expansion of the printing web Web tension values and operating values of the drives determined, and by adjusting the circumferential register on the cylinders or the register rollers is compensated. A The change in transverse elongation determined by a web width detection sensor is transmitted via a change in the setpoint of the tension roll regulated to constant web tension recycled.

In US 30 25 791 A is a method for controlling the drives of a printing press disclosed with the aim of a constant stretch. The measurement of the strain takes place here near the first printing unit by comparing the angular position of the printing unit and then the position of a mark on the substrate. A change in the Relative position between the angular position of the printing unit and the position of the mark a change in tension for the substrate web in the feed unit.

DE 198 34 725 A1 shows several methods for regulating the web tension. in this connection we you. a. measured the web tension and with this measurement the tension on one Target value or a target range for the voltage or to a calculated one Speed for a lag or a lead of a drive over a second Drive returned. The web tension is here by means of a simple or a a predefinable speed setpoint extended web tension control, one Lag rule, with or without DROOP behavior, kept constant.

DE 29 51 246 C2 discloses a device of a printing press by means of which it is possible, the speed of a paper web at different points, in the example the drive of the printing unit on one side and that of the pull roller on the other side, relative to each other. Here are corresponding by means of motor shaft coders the speed of the pulse can be determined, which are fed to an engine control circuit.

The invention has for its object a method for controlling a To create web tension in a rotary printing press.

The object is achieved by the features of claim 1.

The advantages achievable with the invention consist in particular in that Measurement and comparison of the peripheral speeds of the last printing unit and following pull roller can be performed with little effort, without having to operate a high additional measurement effort. The stretching of the The web becomes constant with fluctuating web properties and operating parameters held.

Especially when starting up a printing unit, a printing tower or one entire, multi-web rotary printing press takes place at least temporarily Print job without water and / or paint, d. H. with a dry track. Before one Pressure adjustment of the cylinders takes place before and after the printing units largely same web tension, since the web is not clamped by the printing units. For the However, it is advantageous to run the web, even after printing, but in the Operation without water and / or paint, the web tension before the first and after the last printing unit are approximately the same. This is the case if the Circumferential speeds of the last printing unit and subsequent drawing roller approximately are the same, which can be ensured in an advantageous manner with the invention.

When water and paint are switched on, the stress / strain behavior changes the web as it passes through the pressure points and causes a Tension reduction after the last printing unit, since the subsequent drawing roller initially running at the same peripheral speed as the last printing unit. In order to in multi-lane operation, a trouble-free funnel infeed of the webs is guaranteed to to achieve the necessary gradation in web tension after switching on Only water and / or ink before reaching the production speed if possible the appropriate web tension level of the webs via feed mechanism adjustments coordinated with each other.

The paper web expands under the influence of the dampening solution and / or the color in both the longitudinal and transverse directions based on the transport direction. This strikes, especially in multi-color printing with free path lengths between adjacent printing points, as widening of the printed image or several juxtaposed printed images with progressive path through the Pressure points. This so-called fan-out effect can, as long as the effect on everyone Pressure point remains almost constant over time, at least in part, for example correspondingly spaced apart printing forms are compensated. The However, the stretch behavior of the paper web is subject to many influences, for example the stress / strain characteristics of the respective paper and thus the prevailing tension, the current humidity, the sensitivity to moisture, the penetration behavior and even the position of the roll in its manufacture in Drum, which is reflected, for example, in different winding hardness.

The stretch, both the longitudinal and the transverse stretch, is therefore not because constant paper properties of the rolling paper web itself and because of changing and sometimes fluctuating operating parameters on the printing press stationary. For example, the paper web on the roll is subject to an uneven pattern Winding during production, a location-dependent fluctuation in the modulus of elasticity, or other irregularities. These properties are usually from paper type to Paper type very different. The properties can also change with the same type of paper differ significantly from role to role. On the other hand, affect one fluctuating web tension, changing printing speeds, fluctuations in the humidification or a roll change the stretch of the paper web so that the Elongation in the longitudinal and transverse directions in relation to the transport direction is not temporally are stationary.

Both with fluctuations in the properties of the web, as well as with changing Operating parameters, e.g. B. the dampening, the mathematical correlation is one Leave the stress-strain curve and a currently unknown curve changed. If you continue to regulate only at constant voltage, you will get one Deviation in the elongation and in the effective development length of the printed image the web B with the consequence of errors in the image length on the web B and also in the Scope and / or page registers. The present method overcomes this disadvantage the stretch is also with the above-mentioned. transient web properties and / or Operating conditions kept constant.

In an advantageous manner, the method according to the invention can be used to ensure that the Start-up process guaranteed, a basic setting established, and above further fluctuations in the elongation, in the longitudinal and or transverse elongation, be balanced.

In a special embodiment, the one arranged behind the last printing unit Pull roller in the start-up phase (without paint and water) speed-controlled with regard to a printing unit and torque-controlled during production of a predefinable setpoint. Those still measured in production The speeds of the drawing roller and printing unit are used to control the Pull-in unit used. After reaching the production speed existing difference in the peripheral speeds of the leading in production Draw roller and the peripheral speed of the printing unit form a setpoint. A Changing this difference indicates a change in elongation, longitudinal but also one Transverse stretch of the printing material web, and thus to a change in the image length the path B and / or close in the transverse and longitudinal register. The torque control causes a brief change in the speed of the drive of the pull roller. The relative Speed change in turn now causes the control of the feed mechanism, what ultimately the torque-controlled draw roller return to its "normal operation" leaves. A change in the elongation or tension occurs after the last printing unit measured, however, a regulation takes place on the feed unit, which covers the entire Tension level of the paper web defined. Advantageously, there is no direct Feedback on the traction roller arranged after the printing unit, but one Change in the total tension level in the feed unit. The is particularly advantageous Maintaining a constant web tension behind the pulling roller Combination of the torque-controlled pull roller with the control of the feed unit can be reached via the difference in peripheral speeds without additional measurement and control expenditure.

It is advantageous to determine the change in elongation at the end of the printing tower or behind it the last printing unit, as this is a good one for the further processing steps Provides information about the entire change and a countermeasure in the sense of a allows constant tension of the web for the subsequent paths of the web. In In this sense, it is also advantageous that the control is not in the area of the measuring point, but at the beginning of the course, creating a basic level for the course of the Tension is set without the superstructure, especially in front of the Hopper feed roller can bring about significant changes in web tension.

An almost stationary portion in the longitudinal expansion, e.g. B. for the purpose of presetting the Printing machine for the expected or measured operating and paper conditions, can e.g. B. by register adjustment on the cylinders, by register rollers or other facilities are compensated.

It is also advantageous that both the first-mentioned requirement for a speed-controlled starting, as well as after switching on water and paint the second demand for regulation of changes in the fan-out effect or Cross register and the image length with largely constant web tension the pull roller is fulfilled without, for example, additional systems for Image acquisition or the like would be required to maintain the cross registration.

An embodiment of the invention is shown in the drawing and is in following described in more detail.

Fig. 1

eine schematische Darstellung für die Führung einer Bahn vom Einzugswerk über vier Druckwerke und eine zweite Zugwalze bis hin zu einer Trichtereinlaufwalze;

Fig. 2

eine schematische Darstellung der Bahnspannungsniveaus im Fortdruck.

Show it:

Fig. 1

a schematic representation for guiding a web from the feed unit via four printing units and a second pull roller to a funnel inlet roller;

Fig. 2

a schematic representation of the web tension levels in production.

Fig. 1 shows schematically the course of a path B, z. B. a printing material web B or a paper web B, on its way through a printing press, in particular one Web printing press. The web B runs in the transport direction T from Reel changer 01 via a feed unit 02 with a pull roller 03 through four printing units 06 to 09 to a second pull roller 11. Follow after the second pull roller 11 for example, not shown turning bars, cutting knife, further train or Guide rollers and ultimately a hopper inlet roller 12. The main pull rollers 03 and 11 are each with its own drive 13 and 14 and a drive control 16; 17 equipped. In front of the feeder 02, between the feeder 02 and the first Printing unit 06 and between the last printing unit 09 and the drawing roller 11 and on the free path between the drawing roller 11 and the hopper inlet roller 12 are in preferred embodiment the voltages S1; S2; S3 and S4 of web B measured. This can, for example, via measuring rollers or the power consumption of the drive motors the traction means.

The starting point for setting the web tensions are, especially if in Multiple web operation at the hopper inlet on the hopper inlet roller 12 to several webs B. a multilayer strand, the absolute and relative Tensions S4 of the individual webs B on the hopper inlet roller 12 to one another (several lanes indicated in Fig. 1). As a result, the Tension of the web B starting from the desired level on the Hopper inlet roller 12. This is preferably done by adjusting the feed mechanism 02 Level of web tension set. The web tension is also changed in advantageously by changing the voltage S2 on the feed mechanism 02 Tensioning the web B, the first pull roller 03 is therefore opposite the Machine speed operated with a lag. In production, d. H. at Production speed and with the addition of water and paint, becomes the second Draw roller 11 usually with an advance over the machine speed driven. The machine speed is, for example, on a cylinder 18, for example, a transfer cylinder 18 of the last printing unit 09 measured. The peripheral speed u09 can, for example, Phase position ϕ 09 or the temporal change in the angle of rotation or phase days ϕ ˙09 or the position of a drive 19 or also by a marker and a Detector on the transfer cylinder 18 or another cylinder, such as. B. Forme cylinder or impression cylinder can be determined.

The pull roller 03 and the hopper inlet roller 12 and possibly between the second Pull roller 11 and hopper feed roller 12 lying drives can be used for operation be regulated with production speed and / or rotational position. In particular, the pull roller 03 can be regulated such that the tension S2 between feed unit 02 and first printing unit 06 constantly to a setpoint is returned.

The pull roller 11 is in the print-on position, without water and / or paint, i. H. at dry web B, with regard to its peripheral speed u11 as a controlled variable regulated and operated with water and ink with torque control during production.

When running a dry web B, it is advantageous if 06 and after the last printing unit 09 there are the same voltages S2 and S3. Since in dry condition the web B has no significant stretch due to the influence of moisture the peripheral speeds should be accordingly in this phase u09 of the last printing unit 09 and the peripheral speeds u11 of the drawing roller 11 be about the same. Leading the pull roller 11 would lead to unnecessarily high tensions S3 of web B or even lead to web break. The drive 14 of the pull roller 11 is about the drive control 17 is controlled accordingly by the two Circumferential speeds u09 of the printing unit 09 and u11 of the drawing roller 11 compared and a possibly occurring difference .DELTA.u on that caused by the machine speed specified peripheral speed u09 can be reduced. this happens for example, by increasing the peripheral speeds u11 of the pull roller 11 or is lowered so that almost Δu = 0 applies or Δu within predeterminable Tolerance limits.

When water and paint are switched on, the voltage or Stretch behavior of the web B as it passes through the individual pressure points of the Printing units 06 to 09 and causes the voltage S3 to decrease after the last one Printing unit 09, since for the time being the pull roller 11 is still at the same peripheral speed u11 runs like the last printing unit 09. The pull roller 11 is now in the following and operated under torque control during production. So with multi-track operation a trouble-free funnel infeed of the webs B is preferably preferred to the necessary, known gradation in the voltages S4 of several webs B to reach each other, after switching on water and paint before reaching the production speed, if possible only by adjusting the feed mechanism 02 suitable tension level of the web B. This can be done using, for example the pull roller 03 or one located in the feed unit 02, not shown Dancer roll take place.

A basic setting of the tensions during production, as schematically in Fig. 2 is shown, for example, on the web tension, speed or position-controlled draw roller 03, the also controlled hopper feed roller 12 and / or Dancer rolls not shown manufactured. This usually voltage controlled state the web B takes into account with a lag of the pull roller 03 and an advance of the Pull roller 11 is already a stationary one based on the machine speed (expected or measured) proportion of a change in length of the web B, which gradually during the passage through the printing units 06 to 09 due to the effects of moisture he follows. Symmetrical and stationary fan-out designs in the cross register can also be used already be considered here.

In order to make changes or fluctuations in the cross register or during printing the length of the picture as z. B. when changing roles, when adjusting the fountain solution, at Speed changes, etc. counteract, will Circumferential speeds u09 and u11 continue to be compared and an existing one Difference Δu is stored as reference value Δu-target in the storage unit. This is said in following the same as determining the phase position lage09 or the temporal Change the phase position ϕ ˙09 and a rotation angle or phase position ϕ 11 or the change over time of the phase position ϕ ˙11, a change being the difference Δϕ ˙ is measured and recorded as a Δ˙ ˙ target in the storage unit. Now kick during the production of ongoing production as a result of one of the above Reasons for a deviation in the difference Δu (Δϕ ˙) from the reference value Δu-target (Δϕ ˙-target), this is an indication of Changes in paper properties and / or elongation ε in paper, and thus also for relative changes in the circumference (color) register, in the cross register and / or the Picture length. A greater stretch, for example, leaves the moment on the pull roller 11 drop briefly, whereupon, since it is operated with torque control, with a Increasing the peripheral speed u11 responds. The actual value of the difference Δu gives way now from the previously saved reference value Δu setpoint. This deviation, and with that the deviation in the cross register, the circumferential register and / or the image length is also now compensated with the feed unit 02 upstream of the first printing unit 06 until the torque-controlled pull roller 11 again for the reference value Δu-target required circumferential speed u11 reached. The peripheral speeds u09 of the printing unit 09 and u11 of the pull roller 11 can directly on one of the Printing unit 09 assigned cylinder, for example directly on the transfer cylinder 18th or directly on the pull roller 11, or by means of a drive 14 or 19 arranged encoder or an encoder can be determined. The second The peripheral speed u11 or phase position ϕ11 (ϕ ˙11) can also be at another Roller or another cylinder in the transport direction behind the last printing unit 09 be determined, e.g. B. by means of a rotary encoder on an additional measuring roller.

The deviation from the reference value Δu-target (Δϕ ˙-target) can, for example, be a disturbance variable Δ are superimposed on a setpoint generator of the drive control 16. The drive control 16 of the pull roller 03 can be torque-controlled, for example, one The voltage S2 is fed back. One path of path B via a corresponding one Measuring roller 21 for measuring the tension S2 of web B is shown in broken lines in FIG. 1 shown. The setpoint generator of the drive control 16 is the result of the deviation from Reference value Δu-target corresponding disturbance variable Δ, for example as correction variable ΔS2 superimposed. Such a correction variable ΔS2 can be stored, for example Curve can be taken or iteratively by raising or lowering the Voltage S2 take place until the difference Δu of the peripheral speeds u09 and u11 again corresponds to the reference value Δu target.

The peripheral speeds u09 and u11 are equal to the speed u09; u11 of path B (if path B is curved on the side of the contact) if the Slip is negligibly small. Thus, in a further embodiment of the invention also the speeds u09; u11, or their difference Δu, the path B the disturbance variable Δ can be used for the regulation of the voltage S2 if it is in a different way be won. It is essential, however, that the speed u09 the Machine speed or the speed u09 of the web B in the area of Printing units 06; 07.08; 09 and the speed u11 the speed u11 the Represents web B behind the last printing unit 09. The execution of the Traction roller 11 advantageous as torque-controlled during production.

Abrupt changes in the force acting on web B can be avoided for the roller 03 also on a drive control with DROOP behavior be used. A load-dependent change in the Desired setpoint of a peripheral speed or a speed that both a change in the tension of web B, e.g. B. S4, as well as a change in the Peripheral speed, e.g. B. u11, taken into account. In this case too, the setpoint S2-target, a correction variable ΔS2 is superimposed as an offset for the web tension S2 together with the actual value of voltage S2 using the DROOP function corresponding lagging of the pull roller 03 results.

However the pull roller 03 or the feed mechanism 02 is regulated, so it is essential that the setpoint for the drive control 16 one from the difference Δu determined disturbance variable Δ, for example as a correction variable ΔS2 of the desired one Voltage S2 is superimposed. If necessary or under certain circumstances, the Machine speed instead of the last printing unit 09 in the transport direction T with the peripheral speed u09 also determined on another printing unit 06 to 08 become. The difference Δu and the reference value Δu-target are then, for example, from u11 and u08 etc. to be determined and processed as disturbance variable Δ.

It is also essential that a change in this difference Δu to a change dε Elongation ε, the longitudinal and / or the transverse elongation ε of the web B after the last one Printing unit 09, and thus to a change in the cross registration and / or the image length of the Lane B can close and that this is a short-term change in speed of the drive 14 of the pull roller 11 causes. The relative speed change or deviation of the The difference .DELTA.u from the reference value .DELTA.u target now in turn effects the regulation of the Einzugwerkes 02, which ultimately the torque-controlled drawing roller 11 in their "Normal operation" can return. A change in the elongation or tension will measured after the last printing unit 09, but regulation takes place at the intake unit 02, which defines the total tension level of the paper web B. In advantageous Thus, there is no direct feedback to that after the last printing unit 09 arranged pull roller 11, but a change in the total tension level in the Feed mechanism 02.

Instead of the circumferential speeds u09 and u11, the Angular positions of one of the printing units 06 to 09 and the pull roller 11 are used become. When the strain ε changes, the relative deviation deviates Angular position. This difference value can then be used as an absolute value or as an absolute value Sign can be used as disturbance variable Δ for the control of the drive 13.

The procedure is for printing presses with stacked or side by side, with printing units combined to form bridge or H units, for rubber-against-rubber or rubber-against-steel printing units and other combinations.

LIST OF REFERENCE NUMBERS

01

reelstands

02

infeed

03

pulling roller

04

-

05

-

06

printing unit

07

printing unit

08

printing unit

09

printing unit

10

-

11

pulling roller

12

Former inlet roller

13

drive

14

drive

15

-

16

drive control

17

drive control

18

transfer cylinder

19

drive

20

-

21

measuring roll

B

Train; printing material; paper web

T

transport direction

ε

Strain; Poisson

dε

Change in elongation; Change in transverse elongation

u09

Peripheral speed, speed

u11

Peripheral speed, speed

.DELTA.u

difference

.DELTA.u target

reference value

φ09

Angle of rotation, phase position (09)

φ11

Angle of rotation, phase position (11)

ϕ ˙ 09

temporal change of the phase position (09)

ϕ ˙11

temporal change of the phase position (11)

Δϕ ˙

difference

Δϕ ˙ target

reference value

Δ

disturbance

S1

tension

S2

tension

S3

tension

S4

tension

.DELTA.S2

Correction variable (target S2)

S2 target

Setpoint (S2)

Claims (9)

1. Method of regulating a web tension in a rotary press, a web (B) passing through at least one printing unit (06; 07; 08; 09), and two speeds (u09; u11) being measured at two different points and, as a result of a change in a difference (Δu) in the two speeds (u09; u11), a tension (S2) of the web (B) being regulated upstream of the first printing unit (06), characterized in that by means of the two speeds (u09; u11), a change in the longitudinal extension downstream of the last printing unit (09) is determined and, with this, the tension upstream of the first printing unit (06) is regulated.
2. Method according to Claim 1, characterized in that

   the first speed (u09) is determined as the circumferential speed (u09) on a printing unit (06; 07; 08; 09) and

   the second speed (u11) is determined as the circumferential speed (u11) on a pull roll (11) that follows the last printing unit (09) in the transport direction (T),

   the difference (Δu) of the two circumferential speeds (u09; u11) is recorded as a reference value (Δu-SP),

   during continuous printing, an actual value of the difference (Δu) is compared with the reference value (Δu-SP),

   and in that a deviation of the difference (Δu) from the reference value (Δu-SP) is used as a disturbance variable (Δ) for regulating a pulling mechanism (02).
3. Method according to Claim 2, characterized in that the pull roll (11) is regulated as a function of a predefinable torque during continuous printing.
4. Method according to Claim 1, characterized in that the second speed (u11) is determined downstream of a last printing unit (09) by means of a measuring roll.
5. Method according to Claim 2, characterized in that the second speed (u11) is determined by means of an encoder on the pull roll (11).
6. Method according to Claim 1 or 2, characterized in that the first speed (u09) is determined on the last printing unit (09) as seen in the transport direction (T).
7. Method according to Claim 2, characterized in that the disturbance variable (Δ) is fed to a drive regulator (16) of the pull roll (03) arranged upstream of the first printing unit (06), preferably as a corrective variable (ΔS2) to a set point (S2-SP) for a tension (S2) between pulling mechanism (02) and first printing unit (06).
8. Method according to Claim 1, characterized in that the speeds (u09; u11) are determined as rotational angles (ϕ09, ϕ11).
9. Method according to Claim 2, characterized in that the pull roll (11) is regulated as a function of a speed (u09; u11) during the print-on position without the addition of water and/or ink.

Images