EP1114720B2 - Method for adjusting an air conduit system for a sheet-fed printing machine - Google Patents

Abstract

Characteristic curves drawn using critical sheet conveyance parameters, plotted against optimal sheet parameter of specified printed are stored in memory. Actual specified sheet and printer specification data of print job are input to CPU. Based on the input data, CPU accesses optimum characteristic curve from the memory and outputs appropriate commands to individual actuators and allows operator intervention, if required. An Independent claim is also included for regulating and/or controlling device for air guide system.

Description

The invention relates to a method for adjusting an air duct system in a sheet-fed press. Such air guiding systems are used for conveying and guiding the printing material, generally a sheet of paper or cardboard. Such a system comprises a plurality of different air-assisted elements, such as blow systems and breech cushions, called "actuators" in the context of this invention.

The air guidance system ensures precise conveying and guiding of the single bow held at the front edge by grippers. It depends on the highest accuracy, both the routing, that is avoiding deviations from a specified by the gripper target path, as well as with respect to the timing. With increasing machine speed the problems grow.

The universal applicability of a machine for the thinnest papers (bible printing paper) as well as the strongest cartons requires on the one hand a large adjustment range, and on the other hand an exact adjustment of the air parameters. In particular, this applies to the pressure at the nozzle outlet and thus also the air velocity and the air volume. These air parameters are controlled e.g. by throttle valves or bypass flaps, remotely adjustable engine valves and speed controlled air generators. In the process, the abovementioned parameters decisive for sheet conveyance - hereinafter referred to as "conveying parameters" - must be set to the specific data of the respective print job.

The bow-specific parameters

Sheet-specific parameters are, in particular, the basis weight, ie the weight of the sheet in g / m ² and the sheet format. But other sizes come into consideration, for example, the stiffness of the bow or its surface texture. It is understood that the conveying parameters are to be selected with regard to the sheet parameters in order to achieve an optimum result, that is, a perfect conveyance of the sheet through the entire machine. It may also be the case that the parameters of a blower nozzle when changing the sheet parameters (for example, higher basis weight) must be changed at a certain point of the conveying path in a different way than at another location.

Printing machine-specific parameters

Printing machine-specific parameters are crucial for the work of the blast air nozzles. The most important press-specific parameter is the production speed, ie the machine speed. Further press-specific parameters are the switching on or off of individual printing units, the presence of special inline applications: painting, drying, measuring, cutting.

Combined parameters

Printing form, color assignment, moisture absorption change the substrate properties during the machine run.

In hitherto known printing machines, the air parameters of the individual air consumers, that is, for example, blowing air nozzles, are each individually adjustable. At best, it is known to adjust groups of air consumers. In any event, a large number of adjustments must be made whenever a new print job is executed, with sheet-specific parameters that differ from the previous print job, and / or with other press-specific parameters, such as higher or lower press speeds.

From the abundance of all possible settings, the operator has to find the right setting. The operator must therefore approach the correct values of the delivery parameters empirically in order to achieve a perfect delivery result. In doing so, he or she follows the physical and specific machine-specific and combined parameters mentioned. This not only requires a high level of skill on the part of the operator, but is also time consuming. The operator must decide from the understanding of the technical-physical effect or from his own experience whether corrections upwards or downwards are necessary to optimize the delivery parameters, in particular the air pressure of the tuyeres.

The previous attempts to solve existed in the following:

The performance of the machine has been limited to specific applications, thereby achieving a reduction in the settings of delivery parameters; the air generators were limited in their performance to avoid misadjustments; the control panels and viewing windows next to the curved guideway were designed ergonometrically;
Production with reduced machine speed, because in the day-to-day business of a printing company, the increased set-up time was usually not amortized due to the higher production speed achieved as a result.

All of these attempts were unsatisfactory in terms of the time spent on the quality of the print result as well as the skill and experience requirements of the operator.

EP 0 553 321 B2 describes a device for controlling and / or controlling individual control elements such as blowing nozzles in the region of the boom of a sheet-fed press. This sheet and printing machine-specific characteristics are fed to a computer. A control device makes a format-dependent setting for individual control elements. The computer determines from the characteristics of the energy of the incoming arc in the boom and also ensures that the control variables of the actuating elements apply just as much energy as the energy of the incoming arc in the boom area corresponds.

DE 197 14 204 A1 describes a device for controlling the blowing air at a sheet feeder. In this case, valves that control the supply of blowing air are adjusted on the basis of control characteristics, which in turn take into account the arc properties.

DE 34 13 179 A1 describes a control and regulating device for a sheet delivery of a sheet-fed press. All required settings of adjustable elements of a sheet delivery are set from a single point and automatically adapted to the changing conditions according to a given program.

The DE 197 30 042 A1 shows a device for controlling the blowing and / or Saugluftrate in a sheet-fed press. The press has a computer, with an input for parameters of the sheet and the sheet-fed press. In a memory characteristic curves for setpoint input of the blowing and / or Saugluftrate are deposited, after which an actuator is driven in accordance with the setpoint specification. However, a fine adjustment is made with a non-contact sensor.

The EP 0 503 623 A1 describes a device for controlling the Blasluftbedarfs the separating nozzles in a sheet feeder of a sheet-fed rotary printing press. Here is a computer with sensors for pressure and engine speed and a keyboard in connection, the computer can be acted upon with production data that affect a characteristic for regulating the Blasluftbedarfs via characteristics for type and grammage of the printing material.

The DE-U-29910696 describes a spoiler, which is changed depending on the format It is closed while lying outside the format nozzles. The delivery rate of the air generator is adjusted by means of a curve so that the conditions of radiation on the substrates facing the substrate remain the same. By means of a manually inputable correction factor, the characteristic curve can be raised or lowered in total.

All these suggestions were unable to solve the problems at hand.
In particular, the consideration of parameters not contained in the database is impossible, which in principle leads to incorrect settings.

There is a fundamental contrast between full automation Manual adjustment + fast + flexible + no set-up times + universal - no intervention + maximum power - never covers 100% of all parameters - Setup time very high - many wrong settings - Done in the machine - incomprehensible to the printer not visible - Experience of the printer remains unused - possibility of error

The invention has for its object to provide a method for setting an air handling system for a sheet-fed press, in which the individual delivery parameters of actuators such as Blasluftdüsen quickly and automatically by less experienced staff for certain order data with specific sheet-specific and printing machine-specific Parameters are adjustable (preset and adjustment), and the manual influenceability is maintained in such a way that the advantages of a fully automatic with those of a manual control can be used together, excluding the disadvantages, so that an optimal print result is achieved in no time.

This object is solved by the features of claim 1. Advantageous embodiments emerge from the features of the dependent claims 2-7.

This can be used to optimize machine performance, reduce set-up times, and achieve both quality and output independent of the operator's subjective experience.

According to the basic idea of the invention contained in claim 1 characteristic curves are thus created, in which delivery parameters such as the air blast pressure on press-specific parameters such as the printing speed are plotted, for different print jobs with their sheet-specific parameters such as the basis weight or sheet format.

The characteristics mentioned thus contain the data for optimum setting in each case for a very specific printing material.

The control of the air parameters is carried out by evaluation of said sheet and printing machine-specific parameters. This is a preset (preset) possible. To adapt the machine to order-specific conditions then an operator intervention on the respective data is possible. For this purpose, another size is needed here called "influencing variable". This generates a modified characteristic, which then leads to other air settings.

It is desirable that the preset setting detect all practical cases. However, this is not achieved in practice. However, the aim is to capture a high percentage, for example 80%. In the remaining number of cases, the printer must intervene and make an appropriate adjustment.

According to the invention, it can be assumed in the creation of the characteristics for the optimal conveying parameters of physical, "abstract" sizes, such as the basis weight or the stiffness or the format of the sheet.

• das Hochschlagen des Bedruckstoffes
• das Kontaktdoublieren des Druckbildes
• das Schmieren des Druckbildes
• das Flattern des Bedruckstoffes.

According to the invention, it is provided to leave these variables completely aside and instead to use very specific, result-related variables, such as

• the beating up of the printing material
• the contact duplication of the printed image
• the smearing of the printed image
• the fluttering of the printing material.

The printer can reliably assess these states or phenomena. He can ignore the physical background and the counteracting of him Wirkgrößen. The teaching according to the invention thus consists in the following:

Characteristic behavior of the combination of physical parameters such as weight per unit area, stiffness, centrifugal force, and conveying parameters such as blowing force, air quantity, air pressure are systematically recorded in experiments with the states or events such as beating, duplicating contact, smearing, fluttering. The curves are then filed so that the printer can capture the results of changes as dual decisions of more (plus) or less (minus). He can therefore close the control loop in a qualified manner without any physical know-how.

These typical and indicative sizes could be used either alone or in addition to the physical quantities such as basis weight and stiffness. This is favorable in the case in which a multiplicity of parameters acts, which can not be detected and evaluated in detail.

Example: The printer produces proofs and determines a contact duplication to a certain extent at a certain point. He shares this observation with the machine. The machine has its own algorithm or characteristic. Because of this, it causes a corresponding correction for the relevant air system in the machine.

Such a procedure is especially recommended for repeat jobs, where a job data storage of the type mentioned can take place.

Figur 1

veranschaulicht in schematischer Darstellung eine Bogendruckmaschine mit mehreren Druckwerken.

Figur 2

zeigt Kennlinien, dargestellt als Druck im Lufterzeuger über der Maschinengeschwindigkeit.

Figur 3

veranschaulicht ein Bedienkonzept bezüglich der Bogenführung.

Figur 4

zeigt eine Schar von Basis-Kennlinien.

Figur 5

zeigt eine ausgewählte Kennlinie bei dem Schritt "Preset".

Figur 6

veranschaulicht die Anpassung einer bestimmten Kennlinie.

Figur 7

veranschaulicht das unterschiedliche Ansprechverhalten einzelner Verbraucher bei Vornahme ein- und derselben Korrektur.

Figur 8

veranschaulicht das Geschehen bei Verändern eines Parameters, zum Beispiel des Flächengewichtes.

The invention is explained in more detail with reference to the drawing. The following is shown in detail:

FIG. 1

illustrates a schematic representation of a sheet-fed press with multiple printing units.

FIG. 2

shows characteristics, represented as pressure in the air generator over the engine speed.

FIG. 3

illustrates a control concept with respect to the bowing.

FIG. 4

shows a bevy of basic characteristics.

FIG. 5

shows a selected characteristic in the step "Preset".

FIG. 6

illustrates the adaptation of a specific characteristic.

FIG. 7

illustrates the different responses of individual consumers when making and receiving the same correction.

FIG. 8

illustrates the event when changing a parameter, for example, the basis weight.

In the FIG. 1 Sheet-fed printing machine shown in fragmentary form has three printing units I, II and III. The sheets go through the printing units in the order mentioned.

Each printing unit comprises a inking and dampening unit 1, a plate cylinder 2, a blanket cylinder 3 and a counter-pressure cylinder 4.

Between two successive counter-pressure cylinders is a transfer device. This comprises a gripping device 5 with two grippers 5.1, 5.2, a curved sheet guide plate 6 and a number of blowing devices 7.

The single arch is guided on its way through the mentioned stations by means of an air guidance system. For example, sheet guide plates 6 are arranged in the area of the transfer device. In these nozzles are incorporated, which transport the bow through targeted emerging air currents on the sheet guide in a non-contact floating layer.

Furthermore, blowing devices 7 are arranged, which smooth the sheets to be transported on the printing cylinder to ensure an optimal position of the sheet during printing.

It is understood that more nozzles are provided, but need not be discussed here.

This in FIG. 2 The diagram shown shows a number of characteristics. In this case, the characteristic curve "actual printing material" denotes the characteristic curve determined for a current printing material, and on the ordinate a characteristic value is plotted which relates to the respective air generator, in the present case by way of example the variables mbar and rpm Machine speed, expressed in terms of pressure per hour, and other critical parameters.

The headings above the chart
fan series
floating guide
Paper blowing system in front of printing gap
denote different places where a Lufteinsatz is necessary.

FIG. 3 illustrates the operating concept of bowing. The upper left corner shows the state during the start - see "Preset". The individual parameters are pre-set here.

This in FIG. 3 The pie chart below shows the following: Preset setting covers 80% of all practical cases in an assumed case. This means that in 80% of all cases the determined basic characteristics - see FIG. 4 - for a given machine speed, expressed in terms of pressures per hour, for example, indicating the correct air parameters. But this also means that there are a number of cases where this does not apply. Here, the printer must make an adjustment. In practice this means:

The printer starts from the preset setting and makes some proofs. If the result is satisfactory, he does not need to make any adjustments. But if it is not completely satisfactory, for example, because it goes up with the printing speed, or because the special substrate behaves differently than expected, the printer performs an adjustment ("Adjust" step).

In the case of the illustrated pie chart, it was assumed that this would be necessary in 10% of all cases.

The Adjust step corrects all air consumers. In this case, the individual air consumer can be ordered to deliver more or less air.

By contrast, the step "tuning" relates to influencing the air consumers within a machine relative to one another.

This in FIG. 4 The reproduced diagram illustrates a plurality of basic characteristics. It is plotted on the ordinate a measure of the use of the relevant nip blowing system for the sheet guide plate of a particular printing unit, and on the abscissa, the machine speed.

Each characteristic relates to substrates of very specific basis weights, expressed in g / m ² .

Thus, all air consumers in the machine are set according to a stored characteristic.

FIG. 5 illustrates a selected characteristic at step Preset. The printing material has a basis weight of 90 g / m ² . The machine speed is 12000 prints / hour. On the ordinate results in a value of 40% of the capacity of the air generator.

FIG. 6 illustrates the adaptation of the selected characteristic, that is to say that in FIG FIG. 5 represented characteristic curve by means of "Adjust", "Tuning", and "Expert".

The individual steps mentioned are explained as follows:

adjust:

Due to the printing result, the operator makes a correction to the selected characteristic curve, ie the characteristic curve that is displayed in FIG. 5 is reproduced. Advantageously, this correction is done by adjusting the respective characteristic curve of all consumers (actuators) in the machine. It can be done for example by interpolation between the actual substrate and the next adjacent characteristic.

The step "Adjust" affects all consumers of the machine in an appropriate manner.

Tuning:

The tuning is done for individual printing units or groups of printing units, for example, in the printing units 4 to 8 of a machine.

Expert:

The step "Expert" acts on a single or on all similar actuators of the machine (for example, each on sheet guide plate 1 in printing unit 1 ... 8).

Operator:

The step "Operator" allows you to enter the default setting of the respective actuator without switching on a characteristic curve (compensation off). The value is thus entered directly by the operator. This mode corresponds to operating a machine with throttle points.

FIG. 7 illustrates the different claims behavior of different consumers to a particular correction.

1. A) Ein Verbraucher im kritischen oder stark übersetzten Bereich weist einen großen Unterschiedswert zu den benachbarten Kennlinien auf. Eine Änderung der Einflußgröße bedeutet hierbei eine große Änderung der Luftparameter. Siehe das linke Diagramm von Figur 7.
2. B) Hingegen reagiert ein Verbraucher im unkritischen oder schwach übersetzten Bereich nur wenig auf die genannte Änderung. Siehe das rechte Diagramm in Figur 7. Dieser unkritische Bereich liegt zum Beispiel bei Bogenleitblechen vor. Dabei ist das Geschehen im rechten Diagramm in dessen umrandeten Bereich unten vergrößert dargestellt.

If over the entire machine a correction of the work of the air generator by one and the same measure carried out, for example 5%, by pressing the plus or minus button, the actuators react differently depending on the stored characteristic field:

1. A) A consumer in the critical or heavily translated range has a large difference to the adjacent characteristics. A change in the influence means in this case a large change in the air parameters. See the left diagram of FIG. 7 ,
2. B) On the other hand, a consumer in the uncritical or poorly translated range reacts only slightly to the change mentioned. See the right diagram in FIG. 7 , This uncritical range is present, for example, in sheet guide plates. The events in the right diagram are shown enlarged in the outlined area below.

1. a) durch Aufnahme der nachstehenden zusätzlichen Einflussparameter in das n-dimensionale Parameterfeld, zum Beispiel:
   • Grammatur (sogenanntes Flächengewicht)
   • Format
   • Steifigkeit
   • Geschwindigkeit
   • Bedienereingriff
2. b) durch Verändern eines Parameters, zum Beispiel des Flächengewichtes. Dies erfolgt vorzugsweise dann, wenn zum Reduzieren der Datenmenge mit nur wenigen Einflussgrößen gearbeitet werden soll. Siehe Figur 8. Dabei veranschaulicht das linke Diagramm das Soll-Kennlinienfeld, das mittlere Diagramm die Skalierungsfunktion, und das rechte Diagramm das Steuerungsfeld.

The integration for solving the problem of operator intervention can be accomplished in different ways:

1. a) by including the following additional influencing parameters in the n-dimensional parameter field, for example:
   • Grammage (so-called basis weight)
   • format
   • rigidity
   • speed
   • Operator intervention
2. b) by changing a parameter, for example the basis weight. This is preferably done when you want to work to reduce the amount of data with only a few factors. Please refer FIG. 8 , The left diagram illustrates the setpoint characteristic field, the middle diagram the scaling function, and the right diagram shows the control field.

Another variable besides the machine speed - possibly the only other variable - is converted into an auxiliary variable (0 ... 100%) according to a given rule (scaling function). The operating parameter is then simply added, for example 90 g / m ² >60%; when corrected 2% plus> 62%.

The scaling function illustrates the effects the adjustments made by the printer have on the different grammages. The scaling function thus automatically contributes to the printing material behavior Bill. The control panel shown on the right is the result of the scaling function.

List of reference numbers

1

Inking and dampening unit

2

plate cylinder

3

Blanket cylinder

4

Impression cylinder

5

gripper

5.1, 5.2

grab

6

sheet guide plate

7

blowing devices

Claims (9)

1. Method of adjusting an air guide system that includes various actuators such as blast-air nozzles in a sheet-fed printing press comprising the following steps:

   1.1 characteristic lines are created that include conveying parameters significant for the conveying of the sheets such as the blast-air pressure, plotted against a press-specific parameter such as the press speed, and optimized for sheet-specific parameters such as the grammage or the sheet format;

   1.2 the characteristic lines are stored in a memory;

   1.3 the current sheet-specific and press-specific data of a print job are fed to a CPU;

   1.4 the CPU retrieves the optimum characteristic line for the current data from the memory and provides the corresponding commands to the individual actuators;

   1.5 in the case of an unsatisfactory result, the press operator is given the possibility to intervene in the form of a dual decision of plus in the form of plus keys or minus in the form of minus keys, based on which decision the modification of variables characterizing the printed image or the printing stock is determinable.
2. Method according to Claim 1,
   characterized in
   that the variables characterizing the printed image or the printing stock comprises one or more of the following result-related variables:

   • turning up of the printing stock

   • contact ghosting of the printed image

   • smearing of the printed image

   • fluttering of the printing stock.
3. Method according to Claim 1,
   characterized in
   that with one possibility to intervene (A) in the form of an adjust step, all actuators are changed.
4. Method according to Claim 1,
   characterized in
   that with one possibility to intervene (T) in the form of a tuning step a modification of the actuators in individual printing units or in groups of printing units is carried out.
5. Method according to Claim 1,
   characterized in
   that with one possibility to intervene (E) in the form of an expert step, a modification of a single actuator or of all actuators of a kind is carried out.
6. Method according to Claim 1,
   characterized in
   that with the possibility to intervene (O) in the form of an operator step, the input of a desired adjustment of the respective actuator is carried out without using a characteristic line.
7. Method according to Claim 1, characterized by the following features:

   a diagram is created with the aid of a scaling function, the diagram reflecting the effects of the adjustment for the various grammages and thus takes a printing stock behaviour into account.

Images