DE9218978U1 - Cutting register control device on cross cutters of rotary printing machines - Google Patents

Description

A-1738 21.05.96

- 1 - hohzur

Cut-off register control device on cross cutters of rotary printing machines

Description The invention relates to a

Cutting register control device on cross cutters of rotary printing machines in which printing media webs are printed, whereby markings on printing unit cylinders can be scanned by scanning devices which are connected to a comparison and control circuit in the same way as the scanning device of a driven knife cylinder, whereby the comparison and control circuit influences adjusting devices on printing media webs in such a way that corrections are made in the event of angular deviations between printing unit cylinders and knife cylinders.

A cut register compensation device can be found in the state of the art, DE 36 02 894 C2. Two printing cylinders provided with markings are scanned by scanning devices and transmit the pulses to a comparison and control circuit. This in turn receives pulses from a scanning device that is assigned to a driven knife cylinder. Depending on a comparison of the transmitted pulses, a web deflection roller - here, for example, actuated by pressure medium - is deflected in order to correct the cut register. A closed control cannot be assumed here, since the drives of the printing cylinder and the knife cylinder are not influenced in order to bring the control deviation to zero. By applying actuating devices to the printing medium web, this can be used

With the cutting register compensation device from the state of the art, only the web length can be varied.

A-1738 »·· ·· 21.'Ö5.'$6

Influencing the drive of traction devices for rail transport is not disclosed.

Based on the outlined prior art, the object of the invention is to operate a cross-cutting device arranged downstream of a rotary printing press without mechanical coupling.

According to the invention, this object is achieved in that between rotary encoders of a printing unit and of pulling devices, there is a control circuit for driving pulling devices independently of a control circuit between rotary encoders of the printing unit and of a cutting cylinder for driving the cutting cylinder.

The advantages of this solution are that there are two independent control loops, in which the absolute angle position of the printing unit cylinder serves as a common input variable. With two independent control loops, the cutting register can be achieved by changing the phase position of the cutting cylinder without influencing the speed-dependent web tension. With the help of the control loops, the motor torques of the drive motors can be influenced in such a way that despite occurring disturbances - such as fluctuating paper quality - a correct section of the paper web is always guaranteed.

In a further development of the idea underlying the invention, a sensor for detecting the image position is installed in front of the cutting cylinder of a plano delivery device. If the print image is shifted, this optical sensor can immediately influence an input variable of the control circuit for the cutting cylinder drive, so that an exact cut is always guaranteed.

.:..·..' ' 21.O5.V6

A-1738

- 3 - hohzur

According to the idea underlying the invention, the

combined signals &psgr; of the encoder on the

\ Cutting-actual cutting cylinder and signal U> of the encoder on

_tt . 1 Main-Is printing unit is fed a signal*^ from the sensor. Furthermore,

^v opt
the signal transmitted by the rotary encoder of the printing unit

superimposed by a fixed difference signal. From . Main-Is
the sizes«) of the encoder on the cutter dzy Li nder,

I Cutting-Is

QQ of the rotary encoder on the printing unit- the signal of the

[Main-Is opt

Sensor and the proportional constant K

An input signal is generated at a node using the speed-dependent and ramp-like differential signal indicated. This differential signal enables the manufacture of products with a section length that is divisible by a whole number. In addition, a manual setting (ö) can be made, which

T offset
This is particularly important during the start-up phase. During production, the settings made during the start-up phase are corrected if necessary.

From the listed quantities Qa) .CD ,

_r T Cutting-actual T Main-actual

Qp t &PSgr; and the difference signal is therefore a T offset / opt
Input variable for a signal converter. The

The signal converter is followed by a control circuit in which a Current I with an actual flowing current I

should, is

is constantly compared. The big advantage is that a signal combined from many input variables can be determined very precisely as an input variable in order to then serve as a precise reference variable for a current control loop. An angle control system is therefore superimposed on the control of the motor current.

The further subclaims contain features that characterize the control circuit for the tensioning devices. This control circuit essentially ensures that the tension of the material web to be processed is maintained in a controlled manner, depending on the speed.

&Agr;-1738 .:..'..' *··'···*21.&tgr;&Ggr;5!?6

The present invention is explained in more detail below using a drawing.

It shows:

Fig. 1 shows a schematic machine arrangement consisting of an upstream printing unit and downstream cross cutters,

Fig. 2 a control circuit for the drive of traction devices and

Fig. 3 a control circuit for driving a cutting cylinder.

The schematically shown in Figure 1

The machine configuration includes a plano delivery 1, which is preceded by a printing unit 11 of a rotary printing machine. In the printing unit 11, a material web 2 is printed on both sides and in the plano delivery 1 it is separated into individual sections 3 by a knife cylinder 5, which works together with a stationary lower knife 4. The transport of the material web 2 is carried out by pull rollers 6, and the sections 3 by conveyor rollers 7, which each work together with pressure rollers 8 located opposite them. The cutting cylinder 5 and the pull roller 6 each have their own drive. A rotary encoder 10 is assigned to the printing unit cylinders of the printing unit 11; the angular position of the pull roller 6 can be sensed via a rotary encoder 12, while the rotational position of the cutting cylinder 5, which is provided with at least one cutting knife, can be queried via a rotary encoder 24. A sensor 9 is arranged in front of the lower blade 4 and the cutting cylinder 5 that works with it; it is irrelevant whether this is arranged above or below the material web 2 entering the plano boom 1.

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Figure 2 shows a control loop for driving traction devices.

At a signal node 16, a signal <p from a

T tension actual value is transmitted to the rotary encoder 12 of the tension roller 6. The rotary encoder 10 of the

Printing unit 11, a signal U/ is also sent to the

T main actual signal node 16. After combining both signals, one of which has a negative sign, the resulting angle signal is transmitted to a node 17. At node 17, another signal is added to the resulting signal. Starting from the rotary encoder 10 of the printing unit 11, the signal

C/) on the one hand directly to the signal node

T Main-Is /./)

transmitted, but on the other hand &psgr; a here

I Main-Is indicated by a proportionality constant K, speed-dependent and ramp-like increasing difference signal 15 is added. The addition of the difference signal 15 is speed-dependent, so that the slope of the characteristic curve shown in Figure 2 only reflects the course of one characteristic curve from a family of characteristic curves.

The signal at node 17 from the signals C^ , y^ and

fi Train-Ist ' Main-Ist modified by K determined signal represents the main-Ist I

input variable which is fed to a signal converter 13

There, the conversion of an input signal into an output signal, a current I corresponding to the determined angle deviation is carried out via a

Should
Current regulator 21, which controls a power unit 22, is controlled by

The current I controls the motor torque of a drive 28.

Should
The actual current I is applied to a signal node

Is
with a negative sign. If the

Control deviation between I and I equal to 0,

Target Actual optimal conditions exist. If, however, an angular offset

via the rotary encoders 10 and 12, a

·

A-1738 .I!.'..'*'·'»&bull;&bull;'&Zgr;^&Lgr;&dgr;&Igr;^&oacgr;

To compensate for this angular offset, the corresponding current I«... is calculated, adjusted via the current regulator 21 and thus immediately influences the motor operating torque of the motor drive torque of the drive 28. In this way, a web tension dependent on the speed of the printing unit cylinders of the printing unit 11 is maintained, at which disturbances are immediately compensated.

Figure 3 shows a control circuit for driving a cutting cylinder.

Starting from the rotary encoder 24 of the cutting cylinder 5, a

Signal &psgr; , which shows the actual rotational position of the

I Schnei d-Ist
cutting cylinder 5, with a negative sign, is transmitted to a node 20. A

of the printing unit 11 outgoing signal W becomes

&Ggr; Main-Is one fed to the node 20 and the other is dependent

from SignalC9 a speed-dependent, here by

T Main-Is
a proportionality constant K represented

Differential signal 14 is formed.

The proportionality factor K is used here, for example, to characterize the characteristic curve of the differential signal 14 shown in Figure 3. The speed-dependent determined

Difference signal 14, the signal^ and the signal

/&Lgr;'. Cutting-Is

At node 25 a signal W of the sensor

T opt

I Main-Is T opt

superimposed. The sensor 9 detects any shift in the print image on the material web 2 - for example, as a result of fluctuations in paper quality. At node 25, four input signals are therefore already combined; the result of the combination is transmitted to node 26. In general, the statement applies that the signals already taken into account at node 25

f, CP / r ^unc ä that depending on cutting actual / main actual / opt
r Machine speed Cf formed speed-dependent

7 Main-Is
ramp-shaped difference signal 14 is continuously transmitted in the printing state and thus as input variables

&Agr;-1738 .* : &Igr; * \. ^: .. _# '2UO5 ^# -91

for the angle regulation are available. For the

This does not apply to the setting of 19 W. When setting

TOffset -

The hash configuration is set by the printer W so

/Offset specifies that the cut lies on the section boundary.

Has a stationary production facility been established after production has been ramped up? state, &psgr; becomes irrelevant; the control

/ Offset
occurs automatically through the above mentioned

input variables.

The signal is generated at node 26 and is fed to the signal converter 13; depending on the input signal of the determined angle deviation, a

Current I is calculated, which is fed via a current regulator 21 to

Should
a power unit 22 is transmitted/ which in turn

Motor torque of drive 23 of cutting cylinder 5

The actual motor current I is

Is fed back to a node 27. If the control deviation is 0, there is no need for control. Only when the signals from sensor 9 indicate a shift in the print image, or when there are differences in the signals

and (P changes the cutting actual / main actual
signal converter 13 from node 26. Then

the motor current I is changed accordingly, which results in

Should
This results in a change in the motor torque of the drive 23 of the cutting cylinder 5. This in turn shifts the interface between the cutting cylinder and the lower knife 4 in relation to the running material web 2. By using a high-resolution sensor 9, the cutting register can be kept within the tenths of a millimetre range despite the occurrence of disturbances - such as fluctuating paper quality.

By means of two independent control circuits for the drives 23 and 28, a speed-dependent web tension can be maintained without affecting the accuracy of the section. The accuracy of the section is

&Agr;-1738

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again not reduced by fluctuating paper quality/ since the sensor 9 immediately detects any print image shift and influences the input variable of the control circuit of the cutting cylinder drive 23.

^A " ¹⁷³⁸ .!I.*..* ·..·...* 21.0"5",9"O - 9 - hohzur

Reference symbolsList

1 Plano boom

2 Hateria Lbahn

3 Section

4 lower blades

5 Cutting cylinders

6 Pull roller

7 conveyor roller

8 Pressure rods

9 Sensor

10 rotary encoders (DW)

11 Printing unit

12 encoders (pull system)

13 Sign in

14 Differential signal (speed dependent)

15 Differential signal (speed dependent)

16 knots

17 knots

18 knots

19 Setting specification

20 knots

21 Current regulator

22 Power section

23 Drive (cutting)

24 encoders (cutting)

25 knots

26 knots

27 knots

28 Drive (Train)

Claims (1)

- 10 - hohzur Protection claims 1. Cutting register control device on cross cutters of rotary printing machines in which printing media webs are printed, whereby markings of printing unit cylinders can be scanned by scanning devices which are connected to a comparison and control circuit in the same way as the scanning device of a driven knife cylinder, whereby the comparison and control circuit influences actuating devices on printing media webs in such a way that corrections are made in the event of angular deviations between printing unit cylinders and knife cylinders, characterized in that between rotary encoders (10, 12) of a printing unit (11) and of pulling devices (6) there is a control circuit for a drive (28) of pulling devices (6) independent of a control circuit between rotary encoders (10, 24) of the printing unit (11) and of a cutting cylinder (5) for a drive (23) of the cutting cylinder (5). 2. Cutting register control device on cross cutters according to claim 1, characterized in that the cutting cylinder (5) of a plano boom (1) is Sensor (9) for detecting the image position is arranged in front. 3. Cutting register control device on cross cutters according to claim 2, characterized, that superimposed signals &ggr; of / Cutting-actual encoder (24) on the cutting cylinder (5) and a signal W of the rotary encoder (10) on the printing unit (11) 1 Main Jst Signal CP of the sensor (9) is fed, j opt A-1738 .;&ldquor;·,.* *..·...· 21#fftV9*6 Cutting register control device on cross cutters according to claim 1, characterized in that depending on the rotary encoder (10) of the printing unit speed dependent difference signal (11) transmitted signal &phiv; T main-actual longitudinal difference signal (14) is determined. Cutting register control device on cross cutters according to claims 3 and 4, characterized, that from the quantities &phgr; of the encoder (24) ff, TSchneid-Ist - &psgr; of the rotary encoder (10) and the signal G/ of the T main actual &Ggr; opt Sensor (9) and the speed-dependent determined Difference signal 14 is used to form an input signal of a node (26). Cutting register control device on cross cutters according to claims 3, 4 and 5,
characterized in that the phase position of the cutting cylinder is Setting value (19) &Phi; can be preselected manually. f Offset Cutting register control device on cross cutters according to claim 1, characterized in that a current I of the drive (23) of the Is
Cutting cylinder (5) to a node (27) which is Signal converter (13) is arranged downstream. Cutting register control device on cross cutters according to claim 1, characterized in that from a signal W of the rotary encoder (12) and m I Train-Is
the signal U/ of the rotary encoder (10) to a ) Main-Is
A signal to be fed to the node (17) is generated. ^&Agr; " ¹⁷³ 8 .:;.'..* ·..·...* 21*QV<.9o - 12 - hohzur Cutting register control device on cross cutters according to claim 8, characterized in that the signal transmitted by the rotary encoder (10). a speed-dependent, rising main current
difference signal (15) is superimposed. 10. Cutting register control device on cross cutters according to claims 8 and 9, characterized in that a signal determined at a node (17) is fed to a signal converter (13) which is followed by a node (18) to which a current I of a If the drive (28) of the traction devices (6) is returned becomes.