EP2072253A2 - Method for controlling the tension of a sheet and/or the register - Google Patents

Abstract

The method involves processing a product web i.e. paper (101), in a processing device. Elasticity modulus of a material of the web is changed by dampness entry into the material of the web and/or dampness discharge from the material of the web. A variable e.g. control parameter, input variable, precontrol value and reference value, assigned to the dampness entry into the material of the web and/or the dampness discharge from the material of the web is considered during controlling a web tension and/or a register. Independent claims are also included for the following: (1) a computer program with a program code unit for executing controlling steps of a method for controlling a web tension and/or a register in a processing machine (2) a computer program product with a program code unit for executing controlling steps of a method for controlling a web tension and/or a register in a processing machine.

Description

The present invention relates to a method for controlling a web tension and / or a register, a corresponding computer program and a corresponding computer program product.

Although reference will be made hereafter mainly to printing presses, the invention is not limited thereto, but rather directed to all types of machine tools in which a web is processed. However, the invention can be used in particular in printing presses such as newspaper printing presses, commercial printing presses, gravure printing machines, packaging printing machines or security printing presses, as well as in processing machines such as bag making machines, enveloping machines or packaging machines. The web can be made of paper, cloth, cardboard, plastic, metal, rubber, in foil form, etc.

State of the art

In processing machines, in particular printing machines, a web along driven axes (Bahntransportachsen) such. Pull rolls or feed rolls and non-driven axes such as e.g. Deflection, guide, drying or cooling rollers moved. The web is simultaneously processed by means of usually likewise driven machining axes, for example printed, punched, cut, folded, etc. The processing of the web often results in a change of physical properties of the web, which usually results in the change of the time constants of the control ,

In processing machines designed as printing machines, the web is printed in printing units and dried in subsequent drying plants. In this case, the web is usually supplied in the printing units by means of the applied color also water or liquid or moisture in general, whereby a change in the expansion behavior of the web is brought about, ie the elongation behavior is typically "softer". In the subsequent drying plants this change is completely or partially reversed by the drying taking place, ie the expansion behavior typically becomes "harder". Usually followed by the drying plants again cooling plants, for example. Cooling rollers to cool the heated web. Thus, during processing, there is a constant change in process time constants which depend on the expansion behavior or on the modulus of elasticity of the material of the material web are. As a result, the corresponding controllers are incorrectly parameterized and must be adjusted accordingly soft or slow and tolerant of these changes.

It is therefore the object to provide an improved method for controlling a web tension and / or a register, in which the disadvantages just mentioned are overcome as possible.

This object is achieved by a method for controlling a web tension and / or a register in a processing machine, a computer program and a computer program product having the features of the independent patent claims. Advantageous developments are the subject of the dependent claims and the following description.

In the method according to the invention, a web tension and / or a register of a processing machine for processing a web is regulated. The web is processed in at least one processing device. The modulus of elasticity of the material of the web is changed by a moisture entry into the material of the web and / or a moisture discharge from the material of the web, in particular in the at least one processing device. According to the invention, a variable associated with the introduction of moisture into the material of the web and / or the moisture discharge from the material of the web is taken into account in the regulation.

The invention is particularly suitable for a shaftless printing press. As a register control variable is, for example, a color register or longitudinal register. The assigned size In particular, it may be determined or previously known from machine data. This may in particular be a heating power or temperature of a drying plant, a cooling capacity or temperature of a cooling plant, a drying time or throughput time of the web through the drying or cooling plant or generally by areas of the processing machine. In particular, it should be noted at this point that a drying or cooling of the web also takes place outside of drying or cooling plants and preferably this moisture is also taken into account.

Advantages of the invention

The solution according to the invention overcomes the disadvantages of the prior art. In particular, the controller structure, the controller settings and pilot control values can be adapted or adapted to the influencing variables moisture input and moisture discharge. It is now advantageously possible to change the time constants that influence the process behavior, for example, a web tension or a longitudinal register, and to optimally set the corresponding controllers. It is not necessary to determine the modulus of elasticity consuming, since this or its changes from the associated size can be derived.

Advantageously, the assigned variable is taken into account as a control parameter, as an input variable and / or as a precontrol value of the actual and / or setpoint values. Likewise advantageously, a material characteristic of the material of the web is taken into account.

If the processing machine is designed as a printing machine, for example, a change in the modulus of elasticity or expansion of a material web can be derived from an applied moisture input, for example by means of a printing process, and / or from an acting moisture discharge, for example by means of a drying process. As the size assigned to the introduction of moisture into the material of the web, an amount of ink and / or water to be applied, generally a quantity of liquid, can be used by a printing unit. The size assigned to the moisture discharge from the material of the material web can be a heating power, radiation power (eg UV dryer) and / or temperature of a drying plant, a drying time, for example in a drying plant or in air, a cooling capacity and / or temperature of a cooling plant, For example, a cooling roll temperature, a cooling time, for example, be used when wrapping a chill roll or in air. The drying or cooling time can be determined in a simple manner from the transport speed and the distance to be traveled. It is thus advantageously not necessary to determine absolute values of the modulus of elasticity.

In addition, it is advisable to normalize the values for the moisture input and / or the moisture discharge by means of corresponding material characteristics or, alternatively, to provide the material characteristic as an additional input variable for the control, since changes in humidity usually have different effects on different materials. For example, the printing substrate Film usually stronger in its behavior by drying or temperature and less affected by moisture than paper.

It is advantageous if at least one precontrol value is ascertained on the basis of a measuring run, in particular by means of control engineering consideration of the web tension and / or of the register. Likewise advantageously, at least one precontrol value, in particular constantly, is adapted to the process. Expediently, the processing machine has at least one dampening unit and / or drying plant, wherein the adaptation is carried out on the basis of set and / or actual sizes of the at least one dampening unit and / or drying plant. As nominal and / or actual quantities are in particular liquid amount (amount of ink, amount of water, etc.), dry power, dry setpoint temperature and / or dry-actual temperature, cooling unit power, cooling roller target temperature and / or cooling roller actual temperature suitable , It makes sense to additionally calculate a model of the physical conditions of the material parameters as a function of the adaptation variables.

Expediently, the processing machine is designed as a printing machine and at least one pre-control value and / or at least one initialization value for the adaptation are obtained from data of the prepress.

Usually, in a processing machine, both moisture input in the dampening unit and moisture discharge, for example, are controlled by means of a dryer temperature / performance by the machine control. Thus, in a simple way on the basis of the control variables such as desired dryer temperature, Actual temperature of the dryer, dryer capacity, set temperature of the cooling roller, etc. Pre-control values can be determined. Alternatively, the expected drying or moistening can be obtained from pre-press data. It is possible to obtain from this at least one initialization value for the dynamic adaptation and / or at least one static adaptive value that is not subject to adaptation. Optionally, it is possible to take into account the system behavior, in particular the usually relatively large time constants, of the route dry material web or dampening material web.

The control may include a fuzzy logic based control strategy. This is commonly referred to as fuzzy logic.

It is also appropriate to have a standalone controller setting based on the observed overall system behavior, i. of pre-control behavior. This is often called autotuning.

A processing machine according to the invention has in particular all means for carrying out a method according to the invention.

The invention additionally relates to a computer program with program code means in order to carry out all the control steps of a method according to the invention when the computer program is executed on a computer or a corresponding arithmetic unit, in particular in a processing machine.

The inventively provided computer program product with program code means which are stored on a computer-readable data carrier is designed to perform all the control steps of a method when the computer program is executed on a computer or a corresponding computing unit, in particular in a processing machine. Suitable data carriers are, in particular, floppy disks, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs and the like. It is also possible to download a program via computer networks (Internet, intranet, etc.).

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

The invention is illustrated schematically with reference to an embodiment in the drawing and will be described below in detail with reference to the drawings.

figure description

FIG. 1

shows a schematic representation of a preferred embodiment of a machine designed as a printing machine; and

FIG. 2

shows a schematic representation of a control structure according to a preferred embodiment of the invention.

In FIG. 1 a preferred embodiment of a designed as a printing machine processing machine is generally designated 100. A printing material, for example paper 101, is fed to the machine via an infeed 110. The paper 101 is guided and printed by printing units (dampening units) 111, 112, 113, 114 and is output again by an outfeed 115. The input, extraction and printing units 110 to 115 are positionable, in particular cylinder or angle correctable arranged. The printing units 111 to 114 are located in a web-tension-controlled area between the intake unit 110 and the extension unit 115.

The printing units 111 to 114 each have a printing cylinder 111 'to 114', against which a respective impression roller 111 '' to 114 '' is made with strong pressure. The impression cylinders 111 'to 114' are individually and independently drivable. The associated drives 111 '' 'to 114' '' are shown schematically. The impression rollers 111 '' to 114 '' are freely rotatable.

The pull-in and pull-out units 110 and 115 each have two counter-rotating cylinders which guide the paper 101. Also, the collection and the extension unit 110 and 115 is individually by a drive 110 '''and115''' driven. The collection and withdrawal plant 110, 115 and the printing units 111 to 114 together with the continuous paper 101 form a frictionally connected unit.

During processing, the paper 101 is dried and cooled after each printing operation. For this purpose, a processing unit designed as a drying unit or dryer 121 and a cooling unit or cooling roller 131 is arranged in the section between the first printing unit 111 and the second printing unit 112. Similarly, in the section between the second printing unit 112 and the third printing unit 113, a dryer 122 and a cooling roller 132, in the section between the third printing unit 113 and the fourth printing unit 114, a dryer 123 and a cooling roller 133 and in the section between the fourth printing unit 114 and the extraction unit 115, a dryer 124 and a cooling roller 134 are arranged.

According to the illustrated embodiment of the invention, both the moisture discharge in the driers 121-124 and the chill rollers 131-134 and the moisture input in the printing units 111-114 are determinable and usable as a size affecting the modulus of elasticity of the material for the invention , Furthermore, preferably the moisture discharge from the material of the material web 101 "in air" between the printing units 111-114 and the subsequent driers 121-124 and also between the driers 121-124 and the subsequent cooling rollers 131-134 and between the cooling rollers 131-134. 134 and subsequent works 112-115 are taken into account. For controlling the printing machine including the regulation of the web tension and the web register, a computing unit 200 is provided.

The introduction of moisture is possible, for example, from the prepress stage by evaluating the printing area of the printed image and / or by determining the printing unit. For this purpose, for example, a color quantity meter can be used or the position of the ink fountain key can be evaluated. Finally, the effect of the moisture input and the moisture discharge on the modulus of elasticity can be determined by one or more measuring runs.

The following is with reference to FIG. 2 describes how in the illustrated preferred embodiment of the printing machine, the web tension control and / or the register control can be made taking into account the change in the expansion behavior of the material web.

In FIG. 2 a preferred control structure is shown schematically. For this purpose, a controller 10 is provided, which is equipped with an output 11 for outputting the manipulated variable and a plurality of inputs 12 to 16. The controller 10 is supplied via an input 12, a desired value or the reference variable. Furthermore, the controller 10 is supplied via an input 13 of the instantaneous actual value or the controlled variable. According to the illustrated preferred embodiment of the invention, the controller 10 via the other inputs 14 to 16 for receiving the moisture input and / or the moisture discharge associated sizes.

The controller 10 is supplied via an input 14 a the moisture input into the material of the web associated size. This may in particular be a quantity of ink applied in a printing unit.

The controller 10 is further supplied via an input 15 to the moisture discharge from the material of the web associated size. This may in particular be data of the existing dryers, such as e.g. a dryer capacity or dryer temperature.

Finally, at least one material characteristic value is fed to the controller 10 at an input 16. The regulator 10 is thus advantageously capable of automatically communicating the data obtained with regard to the assigned variables with the material reaction. Likewise, however, a control structure would be conceivable in which no input 16 is provided for at least one material characteristic value, but the quantities are standardized with a material characteristic value even before the transfer to the controller.

Preferably, the controller 10 has further inputs (not shown) for receiving further assigned quantities, as far as they are not known within the controller. In particular, for further determination of the moisture discharge, the transport or machine speed, the distances to be covered between the processing devices and / or an outside temperature, etc., can be made available to the controller.

The controller 10 is configured to derive the change of the modulus of elasticity based on the obtained data concerning the assigned quantities. For example, it is possible to derive a change in the elongation behavior in the web based on the amount of paint applied. Such a derivation can be made, in particular, on the basis of data that is present in a previous one Test drive were won. It is also possible to derive the change in the expansion behavior of the material of the web during drying from the controller input data relating to the drying at the entrance 15. The derivation can take place, for example, taking into account the data taken during a test drive.

According to the described embodiment of the invention, the controller 10, which may be formed as web tension and / or register controller, advantageously in a position to take into account the change in the material of the web during the printing, drying and / or cooling process, so that an optimal adjustment of the controller can be achieved. The necessary in the prior art soft parameterization against changes in the web tension behavior can thus be avoided, which waste is advantageously reduced.

It should be noted at this point that it is the illustrated controller and the inputs and outputs are logical elements whose physical design and number is at the discretion of the expert. In particular, a complete software-based version of the controller is advantageous.

It is understood that in the illustrated figures, only particularly preferred embodiments of the invention are shown. In addition, any other embodiment is conceivable without departing from the scope of this invention.

LIST OF REFERENCE NUMBERS

100 press 101 paper 110 infeed 110 '' ' drive 111, 112, 113, 114 printing unit 111 ', 112', 113 ', 114' pressure cylinder 111 '', 112 '', 113 '', 114 '' impression roller 111 '' ', 112' '', 113 '' ', 114' '' drive 115 excerpt 115 '' ' drive 121, 122, 123, 124 dryer 131, 132, 133, 134 chill roll 10 regulator 11 manipulated variable 12 controlled variable 13 command variable 14 dryer size 15 Printing size 16 A material parameter

Claims (13)

Method for controlling a web tension and / or a register in a processing machine for processing a web (101), in particular a shaftless printing press (100),
wherein the web (101) is processed in at least one processing device (111-114, 121-124, 131-134),
wherein the modulus of elasticity of the material of the web (101) is changed by a moisture introduction into the material of the web and / or a moisture discharge from the material of the web (101),
wherein a moisture in the material of the web (101) and / or the moisture discharge from the material of the web (101) associated with the size of the regulation is taken into account. Method according to claim 1, wherein the quantity assigned to the moisture introduction into the material of the material web (101) and / or the moisture discharge from the material of the material web (101) is taken into account as a control parameter, as an input variable and / or as a pre-control value of the actual and / or desired values becomes. The method of claim 1 or 2, wherein the processing machine is designed as a printing machine (100) and as the moisture entry into the material of the web (101) an amount of liquid to be applied is used by a printing unit (111-114). Method according to one of the preceding claims, wherein the processing machine is designed as a printing machine (100) and as the size associated with the moisture discharge from the material of the web (101) a temperature, heating power and / or radiation performance of a drying plant (121-124), a drying time , a temperature and / or cooling capacity of a cooling plant (131-134) and / or a cooling time is used. Method according to one of the preceding claims, wherein at least one precontrol value is ascertained on the basis of a measuring run, in particular by means of control technology consideration of the web tension and / or of the register. Method according to one of the preceding claims, wherein at least one precontrol value is adapted to the process. The method of claim 6, wherein the processing machine (100) at least one dampening unit (111-114), a drying plant (121-124) and / or a cooling unit (131-134), wherein the adaptation based on target and / or actual Sizes of the at least one dampening unit (111-114), drying plant (121-124) and / or cooling unit (131-134). The method of claim 7, wherein additionally a model of the physical conditions of the material characteristics is calculated in dependence on the adaptation variables. Method according to claim 1, wherein the processing machine is designed as a printing machine and at least one pre-control value and / or at least one initialization value for the adaptation are obtained from data of the prepress. The method of claim 1, wherein the control comprises a fuzzy logic based control strategy. A method according to any one of the preceding claims, wherein a self-contained regulator setting is provided based on the observed overall system behavior. Computer program with program code means for carrying out all the control steps of a method according to one of claims 1 to 11, when the computer program is executed on a computer or a corresponding arithmetic unit (200), in particular in a processing machine (100). A computer program product comprising program code means stored on a computer-readable medium for carrying out all the control steps of a method according to any one of claims 1 to 11 when the computer program is executed on a computer or a corresponding computing unit (200), in particular in a processing machine (100) ,

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