EP1303403B1 - Method for regulating the tension of a web - Google Patents

Abstract

The tension (S) in the paper strip passing through the various printing procedures (06,07,08,09) is controlled by comparing the actual and reference values of the tension and separating the transfer rollers (18) sufficiently to restore the correct value.

Description

The invention relates to a method for controlling a web tension according to the preamble of claim 1.

By the EP 09 51 993 A1 a register-containing drive for a rotary printing machine is known, wherein a longitudinal expansion of the printing material web of Bahnspannungs- and operating values of the drives determined, and compensated by adjusting the circumferential register on the cylinders and the register rollers.

In the DE 42 11 379 A1 are disclosed printing units, the blanket cylinders are mounted in adjustable eccentric bushings, wherein by pivoting about the first eccentric axis a pitching of the cylinder and by pivoting about the second eccentric axis a variation of the impression width of an inking roller to the anilox roller is varied.

The DE 197 53 820 A1 discloses a device for mutual adjustment of printing cylinders, wherein a distance adjustment of the cylinder is controllable in its position.

By the EP 0 767 124 A2 a device is known by means of which the peripheral speeds of a pair of drawing rollers can be varied by changing the distance.

The invention has for its object to provide a method for controlling a web tension.

The object is achieved by the features of claim 1.

The achievable with the present invention consist in particular in that the printing units or units in a simple manner on the prevailing tension or tension of the web, for example, the printing material or paper web, are adjustable. This is done via a change in the Druckbeistellung between the co-acting over the web cylinders, advantageously in "rubber against rubber pressure" of the two cooperating transfer cylinder of a printing unit.

The conveying behavior of the web by a printing machine is subject to many influences, such as the stress / strain characteristic of the respective paper and thus the prevailing stress, the instantaneous moisture, the moisture sensitivity, the moisture penetration into the web, and the position of the roll during its production in the drum, which is reflected for example in different winding hardness and of location-dependent variation in the modulus of elasticity. In addition, it is also dependent on the lifts and the contact pressure.

The conveying behavior of the web through one or more printing units of the printing press can be influenced and regulated in an advantageous manner by means of the method, without a change of blankets of different thickness or a change in the process management, such as a change in the moisture is required. A change in the tension of the web can be counteracted during the continuous printing by changing the conveying behavior. The use of different blankets or different types of paper is possible because by means of the method not with the blanket thickness, but with a change in the distance, the conveying behavior and the print quality can be changed.

Conversely, it is possible to use blankets with different conveying behavior, different quality and / or different thickness, wherein the desired web tension or gradation in the web tension between the printing units is automatically almost constant durable.

For example, rubber blankets of certain manufacturers "negative promoting", d. H. the railway is being "slowed down" and others "positively promoting", d. H. the web is "pushed" in addition to the settlement in the Nippstelle.

The conveying behavior is also dependent on the contact pressure of the blankets and the paper web.

In an advantageous embodiment, the transfer cylinders are driven in pairs with its own drive. The co-operating with the transfer cylinders form cylinder together with inking and dampening units are designed to be driven specifically, and only synchronized with the electromagnetically transfer cylinders. The resulting advantages are u. a. the avoidance of, for example, gear play with mechanical coupling of the transfer and forme cylinder and a nearly torsionally rigid and angle synchronous drive of the forme cylinder with respect to the transfer cylinder. In addition, fluctuations in torque, for example, caused by Verreibwalzen or Heber inking, dampened by the own drives for the form cylinder together with inking and dampening and not transferred to the transfer cylinder. This leads to a largely undisturbed printing.

An embodiment of the invention is illustrated in the drawing and will be described in more detail below.

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 Spannung der Bahn im Fortdruck;

Fig. 3

eine schematische Darstellung eines Gummi-gegen-Gummi-Druckwerkes ohne Darstellung von Farb- und ggf. Feuchtwerk;

Fig. 4

eine schematische Darstellung eines Gummi-/Gegendruckzylinder-Druckwerkes ohne Darstellung von Farb- und ggf. Feuchtwerk;

Fig. 5

eine beispielhafte Abhängigkeit der Sollwerte für die Leistungsaufnahme der Antriebe für die paarweise angetriebenen Übertragungszylinder;

Fig. 6

eine schematische Darstellung des Regelkreises für ein Druckwerk i.

Show it:

Fig. 1

a schematic representation of the leadership of a train from the infeed over four printing units and a second draw roller to a funnel inlet roller;

Fig. 2

a schematic representation of the tension of the web in the production pressure;

Fig. 3

a schematic representation of a rubber-to-rubber printing unit without representation of color and possibly dampening unit;

Fig. 4

a schematic representation of a rubber / impression cylinder printing unit without representation of color and possibly dampening unit;

Fig. 5

an exemplary dependence of the setpoints for the power consumption of the drives for the pair-driven transfer cylinder;

Fig. 6

a schematic representation of the control loop for a printing unit i.

Fig. 1 schematically illustrates the course of a web B, z. B. a printing material web B or a paper web B, on its way through a printing press, in particular a web-fed rotary printing press. The web B runs in the transport direction T from the paster 01 via an infeed 02 with a tension roller 03 by, for example, printing units 06 to 09 to a second draw roller 11. After the second draw roller 11, for example, turner bars, cutting knives, not shown, further train or guide rollers and ultimately a funnel inlet roller 12 follow. The main draw rollers 03; 11 are preferably each with its own drive 13; 14 and a drive control 16; 17 equipped. Before the infeed 02, between the infeed 02 and the first printing unit 06 and between the last printing unit 09 and the tension roller 11 and on the free path between tension roller 11 and the funnel inlet roller 12 in a preferred embodiment, the voltages S1; S2; S3; S4 of the web B measured. This can be done for example via measuring rollers or the power consumption of the drive motors of the tension members.

The starting point for setting the tension of the web B are, in particular when multiple webs B are combined in multi-pass operation at the funnel inlet by means of the funnel inlet roller 12, the absolute and relative stresses S4 of the individual webs B on the funnel inlet roller 12 to each other (multiple tracks in Fig. 1 indicated). Accordingly, the adjustment of the tension of the web B is carried out starting from the desired level at the hopper inlet roller 12. Preferably, the base level of the tension of the web B is set by adjusting the infeed 02. Also, a change in the level of the tension of the web B takes place in an advantageous manner By tensioning the web B, the first tension roller 03 is therefore operated with respect to the machine speed with a lag. In the continuous printing, ie at printing speed and with the addition of water and / or ink, the second draw roller 11 is usually operated with a lead over the machine speed of the rotating cylinder 18, for example the transfer cylinder 18.

The draw rollers 03; 11 as well as the hopper inlet roller 12 and possibly between the second pull roller 11 and the funnel inlet roller 12 lying drives can be controlled speed, torque or rotational position for the production speed with production speed. In particular, the draw roller 03 may be controlled such that the voltage S2 between retraction 02 and first printing unit 06 is constantly returned to a desired value.

When running a dry web B, it is advantageous if prevail before the first printing unit 06 and after the last printing unit 09 and between the printing units 06 to 09 equal voltages S2 and S3 or S5 to S7 of the web B.
With the connection of water and / or color, the stress or strain behavior and the conveying behavior of the web B as it passes through the individual pressure points of the printing units 06 to 09 changes.

A basic setting of the voltages S2 and S3 during the production before the first printing unit 06 and after the last printing unit 09, as in Fig. 2 shown schematically, with conventional control technology, for example via the web tension, speed or position-controlled tension roller 03, the also controlled hopper feed roller 12 and / or dancer rolls not shown. This usually tension-controlled state of the web B already takes into account, with a lag of the draw roller 03 and an advance of the draw roller 11 with respect to the machine speed, a change in length of the web B, which moves to and takes place during the passage through the printing units 06 to 09 by the effects of moisture. Symmetrical and stationary fan-out training in the cross-passport can also be taken into account here.

Also between the printing units 06 to 09 changes in pressure-on position and addition of water and color, when changing to another type of paper or when changing the process parameters such as the addition of dampening solution, the conveying behavior and the voltage S5 to S7 of the web B. When passing through the web B of several printing units 06 to 09, a considerable change in the paper properties can take place as the path in the transport direction T progresses, which in turn causes a different conveying behavior of the web B during its passage through the printing units, for example 06 to 09. For example, depending on the type of paper and the free path between the printing units 06 to 09, the humidity z.T. even before reaching the third pressure point, z. B. here the third printing unit 08, completely penetrated into the web B.

In order to counteract the changes or fluctuations in the conveying behavior and / or the changes in the stresses S5 to S7 of the web B during printing through the printing units 06 to 09 during the printing run, a distance a of the two cylinders 18 acting together in each case over the web B is Printing unit 06, 07, 08, 09 changeable ( Fig. 3 ). This can be done such that a stop for the pressure-on position is changeable. The web B extends between the cylinders a radially movable relative to each other at a distance a and is clamped in the pressure-on position between them. The two cylinders 18, which can be changed relative to one another at a distance a, represent two transfer cylinders 18 in rubber-against-rubber pressure. This change of the distance a, for example by a change Δa between the two co-operating transfer cylinders 18, preferably takes place at the same time a distance b in each case between the transfer cylinder 18 and a cooperating with this cylinder 19, z. B. a forme cylinder 19 is maintained.

Normally, the pressure on or off position of the transmission 18 and forme cylinder 19 takes place relative to each other via pivoting of eccentric bushings which receive the pins of the transmission 18 or forme cylinder 19. The change of the distance a can be done for example by a second device, wherein the change of the distance a may not change the distance b result. This can be achieved for example by a second eccentricity of the journals receiving eccentric bushes. For this change, for example, but also provided on the machine, existing paper thickness setting can be used. With a suitable arrangement of the respective transmission 18 and forme cylinder 19 to each other and almost a linear displacement of the transfer cylinder 18 is conceivable. Preferably, as in Fig. 3 strongly oversubscribed, the change in the distance a on the setting of a second eccentric bushing on one of the two co-operating transfer cylinder 18. The setting of the distance a, in the example setting the second eccentric bush, by means of an actuator 21, for example hydraulically, pneumatically, mechanically , electrically or in combination.

The described change in the conveying behavior by variation of the distance a by a change Δa occurs only in the region in which the web B is still clamped between the transfer cylinders 18, that is to say conveyed. This regulation of the tension of the web B and the conveying behavior therefore takes place in pressure-on position of the co-operating transfer cylinder 18. A pressure gap d between the lateral surfaces of the two acting on the web B transfer cylinder 18 is in the print-on position in each phase less than or equal to the thickness of the web B at the appropriate location.

If a change in the conveying behavior of the web B occurs at one or more printing units 06 to 09, then a change in the distance a, for example by the value of the change Δa, is possible, which results in an increase or decrease in the size Pressure gap d has the consequence. The setting of the actuator 21 and thus the change Δa of the distance a can be done by the operator himself, for example, from a control center via a value transmitted to the actuator 21 for the change Δa as a control value Δa or at the printing unit by pressing a corresponding button. For example, the actuator 21 adjusts a stop against which the respective transfer cylinder 18 is set in the print-on position. During production, the operator can thus influence the conveying behavior of the web B between the printing units 06 to 09 during ongoing production.

In a preferred embodiment, the regulation of the conveying behavior of the web B between the printing units 06 to 09 takes place automatically and is integrated, for example, in a control concept for the tension of the web B, which stresses and strains before the first printing unit 06 and after the last printing unit 09 for compensation of changes in the elongation of the web B due to changes in the paper property.

The regulation of the conveying behavior of the web B in or between the printing units 06 to 09 is advantageously carried out via characteristic quantities of the drives 22. An actual value X- _{i in} a parameter X- _i is measured on the drive 22 in the printing unit i and with a setpoint value X. -Soll _i compared. A deviation Δ _i is used to control and if necessary to change the distance a between the cylinders 18th The drive 22 of the transfer cylinder 18 is preferably regulated to a constant peripheral speed or angular speed.

The regulation of the conveying behavior of the web B in or between the printing units 06 to 09 preferably takes place via a power input P- _i (for printing unit i) of the drives for the cylinder B acting together with the web B, in the example of the transfer cylinder 18 the inflow of the forme cylinder 19 and possibly with these mechanically coupled inking and / or dampening units (not shown) in the To keep measurement of power consumption as low as possible, preferably each of the two transfer cylinders 18 per printing unit 06 to 09 in pairs by their own drives 22, and driven together with these forme cylinder 19 together with the associated color and possibly dampening units driven by their own drives 23. Each pair of transfer cylinders 18 is mechanically coupled in one embodiment of the invention, for example via gears or belts. However, it can also be individually driven and electronically synchronized each transfer cylinder 18. A change in the voltage or the conveying behavior entails a change in the power consumption P- _i in the preferably speed-controlled drives 22.

The power consumption P-Ist _i by the drives 22 of a cooperating with the web B pair of cylinders 18, provided that it is standardized accordingly, a measure of the per unit time performed by the drive 22 work, which in turn is a measure of the conditions Voltages S2; S5; S6; S7; S3 before and after the cylinders 18 and for the conveying behavior of the web B represents. Accordingly, setpoint values P-set _i (printing unit i) for recording the power of the drives 22 are set for the successive printing units 06 to 09. These are usually different from one another for the printing units 06 to 09, which are consecutively traversed in the transport direction T ( Fig. 5 ). In the example, these setpoint values P-set ₀₆ from the first printing unit 06 with P-set _{06 increase} approximately 4 kW to the fourth printing unit 09 with P-set ₀₉ approximately 7 kW. However, desired values ΔP _{i, j} -Soll in the power consumption of the differences ΔP _{i, j} = P-actual _{i -P} actual _{j of} two successive printing _units i and j, for example ΔP _07.06 = 1 kW, can also be specified as desired values ,

The instantaneous power consumption P-Ist _i is compared with the respective setpoint value P-setpoint _i or the differences ΔP _{i, j} with the setpoint value ΔP _{i, j} -soll. If a deviation Δ _i and Δ _{i, j} from the target value P target _i and .DELTA.P _{i, j} -Soll measured, this is as shown schematically in Fig. 6 shown processed in the control loop and a change in the distance a by the value Δa effected via the actuator 21. This results in a larger or smaller pressure gap d or blanket overhang between the two co-operating transfer cylinders 18 and thus a changed conveying behavior of the web B in the relevant printing unit i (with i from 06; 07; 08; 09). The changed conveying behavior of the web B in turn alters the power consumption P- _{i of} the drive 22 of the ith printing unit. This power consumption P-Ist _i is monitored and fed back into the control loop.

To control the printing gap d in the print-on position, d. H. If the web B is clamped between the transfer cylinders 18 and thus conveyed, other suitable parameters from the drives 22 can be used. Measurements for the voltage S5 to S7 between the printing units 06 to 09 can also be used for the regulation of the distance a or of the printing gap d. However, the use of already existing performance data is advantageous since this requires little additional effort.

In the case of constant-torque controlled cylinder 18; 23, the characteristic z. B. be an angular velocity, which changes with changing voltages or conveying behavior. This change can now be counteracted again with the change of the distance a.

Does the transfer cylinder 18 via the web B not with a second transfer cylinder 18 together, but with an impression cylinder 23 (FIG. Fig. 4 ), the transfer cylinder 18 is set to the impression cylinder 23 via the web B for printing-on position or vice versa. To change the voltages S5 to S7, the distance a between the transfer cylinder 18 and the cooperating impression cylinder 23 is changed. Both can act on the web B cooperating cylinder 18; 23, z. B. two blanket cylinder 18 or a blanket-18 and a counter-pressure cylinder 23, in order to change the distance a to be moved. The described method also includes variants wherein a counter pressure cylinder 23 cooperates with two or more transfer cylinders. Changes in the respective tension of the web B in pressure-on position take place by the distance a between the impression cylinder 23 and the blanket cylinder 18 is varied.

The two on the web B cooperating, and these clamping cylinders 18; 23 may also be arranged elsewhere in a printing machine, in a paper machine or a rolling mill, for example in a painting, a dryer, in the superstructure, a coating or rolling device, a calender or in any other B a leading devices.

A change in the voltage conditions or a change in the conveying behavior is determined by a parameter characterizing the voltage conditions. It can also be a different size than the power consumption P-Ist _i , z. B. a change in angular velocity in the case of constant-torque controlled cylinders 18; 23, or be a direct voltage measurement. The change of this size represents a measure of the mutually influencing variables "voltage" and "conveying behavior". In particular, it shows a change in the ratios of the voltage S2; S3; S5; S6; S7 of the web B before and after the printing units 06; 07; 08; 09 or a change in the resulting conveying behavior. The deviation of the parameter characterizing the stress ratios from the desired value X-target _i is now used to control the distance a between the cylinders 18; 23 to change.

The printing units 06; 07; 08; 09 are thus at an approximately constant voltage S2; S3; S5; S6; S7 of the web B before, behind and / or between the printing units 06; 07; 08; 09 adjustable.

LIST OF REFERENCE NUMBERS

01

reelstands

02

infeed

03

pulling roller

04

-

05

-

06

Printing unit, first

07

Printing unit, second

08

Printing unit, third

09

Printing unit, fourth

10

-

11

pulling roller

12

Former inlet roller

13

drive

14

drive

15

-

16

drive control

17

drive control

18

Cylinder, transfer cylinder

19

Cylinder, forme cylinder

20

-

21

actuator

22

drive

23

Impression cylinder

B

Train; printing material; paper web

T

transport direction

a

Distance (18)

b

Distance (18, 19)

d

nip

S1

tension

S2

tension

S3

tension

S4

tension

S5

tension

S6

tension

S7

tension

.DELTA.a

Change, control value

Δ _i

deviation

ΔP _i ,

difference

ΔP _{i, j} -Soll

setpoint

P-Is _i

Power consumption for printing unit i, with i = 06 to 09

P-set _i

Setpoint for printing unit i, with i = 06 to 09

X-Is _i

actual value

X-target _i

setpoint

Claims (9)

1. A method of regulating the tensioning (S2; S3; S5; S6; S7) of a web (B), wherein the web (B) is clamped between a pair of cylinders - co-operating by way of the web (B) - with a first cylinder (18) and a second cylinder (18; 23) in a printing couple (06; 07; 08; 09) of a printing press, and an actual value (X-Ist_i) of a parameter characterizing the ratios of the tensioning of the web (B) upstream and downstream of the cylinders (18; 23) is measured and is compared with a nominal value (X-Soll_i), characterized in that a change (Δa) in a distance (a) of the cylinders (18; 23) of the printing couple (06; 07; 08; 09) which co-operate with the web (B) is made with reference to a deviation (Δ_i) of the measured actual value (X-Ist_i) from the nominal value (X-Soll_i).
2. A method according to Claim 1, characterized in that the two cylinders (18; 23) are driven by at least one drive (22).
3. A method according to Claim 2, characterized in that the actual value (X-Ist_i) of the parameter is determined at the drive (22).
4. A method according to Claim 3, characterized in that a power consumption (P-Ist_i) of the drive (22) is recorded as an actual value (X-Ist_i), and a nominal value (P-Soll_¡) for the power consumption is pre-set as a nominal value (X-Soll_i).
5. A method according to Claim 1, characterized in that the two cylinders (18) co-operating with the web (B) are constructed in the form of transfer cylinders (18) and are driven by a common drive (22).
6. A method according to Claim 5, characterized in that the transfer cylinders (18) co-operate in each case with a forme cylinder (19), and the said forme cylinder (19) is uncoupled mechanically from the drive (22) of the transfer cylinder (18).
7. A method according to Claim 1, characterized in that the first cylinder (18) is constructed in the form of a transfer cylinder (18) and the second cylinder (23) is constructed in the form of a counter-impression cylinder (23) co-operating by way of the web (B), and the transfer cylinder (18) co-operates with a forme cylinder (19) uncoupled mechanically from the drive (22) of the transfer cylinder (18).
8. A method according to Claim 7, characterized in that a change (Δa) in the distance (a) between the transfer cylinder (18) and the counter-impression cylinder (23) is made.
9. A method according to one of Claims 6 or 8, characterized in that a distance (b) between the transfer cylinder (18) and the forme cylinder (19) co-operating with it is kept substantially constant when changing the distance (a) by the change (Δa).

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