EP2008815B1 - Method and device for applying a dampening solution or a paint - Google Patents

Abstract

The method involves applying a fluid during rotation of a rotation body (2) in pulses, and simulating a topographic fluid allocation of the rotation body after surface covering and film thickness are equivalent in a mathematical model. Duration of the pulses or distance between the pulses is adjusted depending on the simulated fluid allocation. The topographic fluid allocation is simulated regarding a film division in the model. An outer circumferential surface of the rotation body in the model is divided into lines. An independent claim is also included for a device for applying fluid to a rotation body of a printing machine.

Description

The invention relates to a method and a device for the application of a fluid to a rotary body of a printing press. The fluid may be a dampening solution or paint. The printing machine is preferably a rotary printing machine and may be in particular a web-fed printing press. It prints preferably in offset, preferably with ink and dampening solution.

From the WO 2004/039587 A1 is a method for adjusting a spray dampening with intermittently a fountain solution dispensing spray nozzles known. To prevent unwanted superimposition of sprayed dampening solution on rollers of the dampening unit, the period or spray frequency of the spray nozzles is set in a certain correlation to the rotation time or rotation frequency of a plate cylinder or a dampening roller.

The document WO 2006/013178 A1 discloses a device for applying a fluid.

It is an object of the invention, using a dispenser which intermittently dispenses a dampening solution or ink, i. H. emits pulse, the dampening solution or the color according to the need to deliver to a rotating body of a dampening or inking unit. Overlays should be prevented as much as possible.

The invention is based on a method and a device for applying a fluid, namely a dampening solution or a paint, to a rotary body of a printing press, in which the fluid is intermittently applied in pulses to the rotating rotary body. The device accordingly comprises a dispenser for the intermittent delivery of the fluid and the rotary body rotatable about a rotation axis. The rotary body may be a printing form cylinder if the dispensing device delivers the fluid directly to the printing form cylinder. More preferably, at least one rotary body of a dampening unit or inking unit on the Path of the fluid between the dispenser and the plate cylinder arranged. This rotation body can be formed in particular as known from wet or inking units as a roller. The dispenser preferably has no direct contact with the rotary body. A contactless fluid application to the rotary body has the advantage that color transferred back from the printing process can not be transported into the dispenser of a dampening unit or rewetted dampening solution into the dispenser of an inking unit. Preferably, the dispenser is a spray nozzle. An example of a spray nozzle describes the WO 2005/065948 Al , Along the rotation body are axially offset from each other preferably a plurality of dispensing devices of the same type arranged and jointly or individually controlled.

The dispenser discharges the fluid in pulses. During the period of a pulse, which may be, for example, several milliseconds, a passage of the dispenser is open and allows the fluid to pass under pressure. The pulse duration is followed in each case by a pause duration during which the delivery device is closed and does not deliver any fluid. The pause duration can also be in the millisecond range. It is preferably longer than the pulse duration. Thus, a period of the dispenser, in each of which one of the pulses is delivered, for example, be 50 to 100 msec, wherein the pulse duration, for example, 3 to 20 msec and the pause duration in the example chosen 30 to 97 msec. Instead of a preferred dispensing device, which is reversible between the open state and the closed state, it is also possible to use a dispensing device which can be reversed between a high and a low dispensing rate or in which the transitions are continuous. The period may be variable, but is preferably constant. In the following, it will be referred to as a time interval in general terms. The dispenser dispenses the fluid in successive time intervals in each time interval per one pulse of a pulse duration, which is preferably variable. Preferably, a pulse interval can be varied. The pulse interval is the time from the beginning of a pulse to the beginning of a next pulse.

According to the invention, the transfer of the fluid in the dampening unit or inking unit is simulated in a mathematical model during the printing operation. The model simulates that Behavior of the dampening unit or inking unit. Specifically, it simulates the rotational movement of the body of revolution and the topographical surface occupation of the body of revolution with the fluid, which is intermittently applied by means of the dispenser to the body of revolution in pulses and transported away from the body of revolution in the direction of a printing material to be printed. The model runs in the printing operation according to the rotational speed, preferably of the printing forme cylinder to which the fluid is transferred, preferably in real time parallel to the actual printing process. The printing material to be printed is preferably a web material and may in particular be a paper web, for example for printing a newspaper, but in principle may also be printed in the form of sheets. The model images the outer peripheral surface of the rotating body and simulates, ie, constantly determines a film thickness equivalent of the fluid present on the peripheral surface.

In the tracking model, the current topographical fluid occupancy of the rotational body is continuously determined during the printing operation. Depending on the current fluid occupancy, the duration of the respectively next pulse or the time interval of the respectively next pulse from the preceding one is or will be set. Depending on the rotational speed of the rotating body, the model sequentially generates data records which respectively represent the current fluid occupancy. If the model is running in real-time as preferred, it generates a data set representing the instantaneous and therefore up-to-date fluid occupancy with each revolution of the body of revolution. If the model is not running in real time but slows down, it is possible to interpolate between the individual calculation steps by means of default values, which are preferably adjusted during printing operation by measuring the film thickness equivalent.

The topographical surface coverage determined by the simulation thus comprises the information about a specific location of the peripheral surface and the film thickness at this location, ie is a fluid relief. The location may be a point or a line or partial area, preferably an axial strip or an axial line in the model. be on the peripheral surface of the rotating body. The film thickness equivalent is a value representative of the film thickness at each location, which may correspond directly to the simulated film thickness. Instead of directly determining the film thickness, for example, the Fluid quantity or another physical quantity determined grazing, from which clearly and completely on the film thickness can be concluded. In this sense, the value is equivalent to the film thickness.

For the modeling and the simulation of the area occupation, the device comprises a data processing device, preferably an electronic data processing device. The model may be hardwired in the data processing device. More preferably, it is programmed, d. H. implemented in the form of software. The data processing device is coupled to a controller for the dispenser or integrated part of such a controller. The control device serves to set the pulse duration or the pulse interval between two successive pulses of the delivery device. By means of the control, either only the pulse duration or only the pulse spacing or both in combination can be changed and adjusted in this way, so that the fluid is delivered to the rotational body according to the demand determined by the simulation.

The fluid is preferably applied so that a predetermined desired value is maintained.

In preferred first embodiments, the desired value is predetermined as the ratio of the pulse duration and the length of the time interval in which the respective fluid pulse is applied. The desired value predetermined in this way is preferably delivered as a function of the peripheral speed or rotational speed of the rotary body, to which the dispensing device applies the fluid or which receives the fluid from this rotary body. Preferably, the desired value is varied as a function of the speed of a printing forme cylinder to be occupied by the fluid. Due to the variation of the desired value, the fluid application is adjusted to a fluid requirement that changes as a function of the machine speed

In preferred simple variants of the first embodiment, the lengths of the time intervals are kept constant or can not be varied from the outset, and the required amount of fluid is applied per time interval by varying the pulse duration. In other variants, the length of the time interval can be varied, optionally in combination with a variation of the pulse duration. The ratio setpoint pulse duration / time interval must not be maintained exactly for each time interval. Not least in order to avoid periodic fluctuations in the actual film thickness that is actually established, it can be advantageous if the fluid is dispensed averaged over a number of successive time intervals in accordance with the desired value. Such a delayed or alternatively anticipatory fluid application may also be made in embodiments in which it is not possible to set the set point as the setpoint exactly for each time interval because, for example, the controller or model does not work or work fast enough for it. Is at a period, d. H. given a set time interval of, for example, 100 msec, a pulse duration of 8.4 msec corresponding to a target value of 8.4% and the cycle time of the simulation is 1 msec, then this setpoint may be delivered averaged over several successive time intervals before or after the latency For example, with pulse durations of three times 8 msec and twice 9 msec in all possible sequences, for example 8, 8, 8, 9, 9 msec or 9, 8, 8, 9, 8 msec, or with larger deviations from the mean value forming setpoint.

In second embodiments, the topographical area occupancy of the printing form cylinder is predetermined and calculated back on the transport path of the fluid to the dispenser on the pulse duration or the pulse distance of the dispenser to set or maintain the predetermined area occupancy of the printing form cylinder. In simple first variants, it is assumed that the printing form cylinder emits a constant quantity of the fluid in each time unit in a transfer cylinder which is in pressure with the printing material or preferably on the printing material over its axial length in a gap in which the fluid transfer takes place. This amount of fluid is predetermined in the model and replenished by the dispenser. The predetermined for the printing forme cylinder fluid relief thus changes in the printing operation corresponding to the constant transfer rate in the gap In a second variant, a target assignment is specified for the plate cylinder. As a target assignment can in particular a constant film thickness of the fluid can be specified over the circumference of the printing forme cylinder. The two variants can be combined, so that in such a model at a given, for example, constant desired thickness of the fluid film, the transmission rate in the fluid discharging towards the printing material gap is also specified, for example as a constant transfer rate. The data processing device calculates the pulse duration and the pulse interval of the output device on the basis of a target / actual comparison of the predetermined relief, ie the predetermined topographic area occupation, and the area occupation resulting after passing through the gap, and adjusts the two parameters in such a way that the printing form cylinder adjusts the predetermined area occupancy before the axial line on the peripheral surface of the plate cylinder, which has just passed through the gap, the gap passes a next time. Optionally, the data processing device and the controller can also be set up so that the predetermined area occupation is only obtained again after more than one revolution of the printing form cylinder.

If the rotational body to which the delivery device discharges the fluid directly, preferably not around the printing form cylinder, but around a rotary body of the dampening unit upstream of the printing forme cylinder, becomes the required surface coverage of the upstream rotational body in the second embodiment from the specifications for the printing forme cylinder determined and controlled according to this determined area occupancy the dispenser, d. H. the pulse duration or the pulse interval is set.

The simple specification of the desired value as a ratio can also be combined with the specification of a nominal assignment according to the second embodiments. Thus, a comparison with a nominal assignment can be made, for example at greater time intervals for checking purposes, in order to adjust the ratio setpoint in the event of a detected deviation ,

The peripheral surface of the rotary body can be represented in the model by lines, preferably by parallel to the axis of rotation of the body of revolution, ie axial lines which follow one another in the circumferential direction. The lines can For example, a distance of 1 mm or interpreted as strips have a line width of, for example, 1 mm. For each line, for the rotating body rotating in real-time simulation, the film thickness equivalent, preferably the amount of fluid, or rather directly the film thickness, is determined, which results from the supply and removal of fluid per line.
The model can be implemented in particular as a spreadsheet program. If the outer circumferential surface of the printing forme cylinder and preferably at least one further rotary body of the dampening unit or inking unit are each represented by lines which follow each other in the circumferential direction, a table is created for each such rotary body. Each table preferably consists of a number of lines which corresponds to the number of lines of the respectively associated rotating body. The table values in the rows of the respective table represent the film thickness or the fluid amount or another film thickness equivalent of the associated row of the respective rotary body. If the fluid is transferred as preferred via at least one rotary body to the printing plate cylinder, which itself is also regarded as a rotary body within the meaning of the invention, in the model, so to speak, the tables circulate on behalf of the physical rotary bodies. In this simulated rolling, the two rows of two tables, which represent rotating bodies rotating against each other, virtually enter an overlap such that fluid is transferred between these two rows of the two tables according to the real film splitting. In simple embodiments, the film splitting is simulated by adding the table values of the table rows currently forming the gap in the simulation and halving the sum, so that the two table rows which have just passed the gap in the simulation have the same value after passing. Depending on the viscosity of the fluid, instead of the arithmetic mean, a different ratio for an unequal distribution onto the rotational body forming the respective transfer gap with each other can also be used in the model calculation.

Instead of dividing into rows, the peripheral surface of the rotary body may also be divided into columns which extend in the circumferential direction and are arranged axially next to one another. The model can also be implemented in such executions as a spreadsheet program. For the division into columns, the Comments on the lines mutatis mutandis, A division into columns is advantageous if a plurality of independently controllable dispensing devices are arranged axially adjacent to each other, so that the fluid occupancy can be varied by the application along the rotational body.

In a further development, the peripheral surface of the rotation body is modeled as a grid with grid-determining rows and columns which intersect each other and in each case form a grid location as a point or area in the crossing areas. For the rows and columns, the statements made above apply preferably. When implemented as a spreadsheet program, the table representing the rotation body comprises rows and columns with at least one table space per grid location. The table value of the respective table space is the film thickness equivalent for the assigned grid location.

The fluid is preferably applied to the rows or columns or grid locations that have a lower film thickness equivalent to the model than others. When dividing into lines, for example, the line with the lowest film thickness equivalent can be determined by comparing all the lines. The fluid is then applied to this line. It is also possible to determine several lines per revolution which have the lowest film thickness equivalent and fluid are applied to these lines. If the fluid application is sufficiently fast and accurate, only that line (s) will receive or receive fluid. With a line width of preferably at most 10 mm, more preferably at most 5 mm, a limited to individual lines application of the fluid should not be possible, at least in the continuous printing at the then high rotational speeds. It may therefore be more advantageous if, for a plurality of circumferentially immediately successive lines, a cumulative film thickness equivalent, for example, is determined as the moving average and the minimum of the moving averages is determined. The rows can also be combined into locally fixed groups, preferably each with the same number of lines which follow each other in the circumferential direction, the film thickness equivalents of the rows of the respective group are summed and the minimum sum value can be determined from the comparison of these sum values. The number of consecutive lines that are summed over is advantageously length tuned to the time interval within which the dispensing device emits one of their fluid pulses. Preferably, an absolute minimum or a plurality of local minimums of the film thickness equivalent is determined for each revolution or possibly also only over several revolutions of the body of revolution to which the fluid is applied or of another body of revolution receiving the fluid from or via this body of revolution. At least one fluid pulse is preferably applied to the rotary body during each revolution, in the case of subdivision additionally in columns also at least one pulse per column.

In newspaper offset printing, the preferred field of application of the invention, the printing form cylinder typically axially next to each other several printed images corresponding to one newspaper page on a downstream transfer cylinder, preferably a blanket cylinder, and this transmits the printed images on the paper web, the device of the invention has per printed image, in the preferred application per Newspaper page, several, for example, two delivery devices axially side by side. In the case of four printing forms affixed axially next to one another on the printing plate cylinder or printed images formed directly on the cylinder, the device accordingly has n side-by-side delivery devices, for example spray nozzles, at n delivery devices per printed image. In six-page-wide printing presses, it has 6n dispensers adjacent to each other. The lines of the model, d. H. The rows of the table can correspond per print image to a row on the peripheral surface of the rotary body that extends axially over the entire print image. In such embodiments, at least the respective printed image is not divided axially again. In the above development, the printed images may be divided axially according to the number of nozzles. In principle, however, it suffices if the lines in the model extend continuously over the entire axial length of the respective rotational body or printed image over which fluid is transferred.

If the dampening unit or inking unit comprises one or more rotary bodies in order to transfer the fluid delivered by the dispensing device to the printing form cylinder via one or more transfer gaps, it is advantageous if at least two of the rotary bodies differ in scope, preferably a non-integer one Factor. The printing forme cylinder is calculated for the at least two rotational bodies. If the dampening unit or inking unit has a plurality of rotary bodies, preferably more than two of the rotary bodies are distinguished, wherein in turn the printing form cylinder is counted as a rotary body, in each case in pairs in the circumference of one another, preferably in each case by a non-integer factor. It is particularly advantageous if the rotary bodies, including the printing forme cylinder, which form a transfer gap for the fluid in pairs with each other, each differ in scope, preferably by a respective non-integer factor.

Further features of the invention are described in the subclaims and their combinations.

Figur 1

einen Druckformzylinder mit einem zugeordneten Feuchtwerk,

Figur 2

den Druckformzylinder mit Feuchtwerk und einer schematischen Darstellung eines Modells zur Simulation des Verhaltens des Feuchtwerks im Druckbetrieb und

Figur 3

eine Steuerung und Datenverarbeitungseinrichtung des Feuchtwerks.

Hereinafter, an embodiment of the invention will be explained with reference to figures. The features disclosed in the exemplary embodiment advantageously each individually and in each combination of features form the subject matter of the claims and also the embodiments described above. Show it:

FIG. 1

a printing forme cylinder with an associated dampening unit,

FIG. 2

the printing forme cylinder with dampening and a schematic representation of a model for simulating the behavior of the dampening unit in the printing operation and

FIG. 3

a controller and data processing device of the dampening unit.

FIG. 1 shows a printing form cylinder 5 of a web-fed rotary printing press and a printing forme cylinder 5 associated dampening unit. The dampening unit comprises a dispensing device 1 for a non-contact application of a dampening solution, which is hereinafter referred to as fluid, and a rotary body 2, on whose outer peripheral surface the dispensing device 1 applies the fluid. The dispenser 1 is a spray nozzle. The rotary body 2 is a roller, in the embodiment, an axially iridescent in printing operation back and forth distributor roller, the dampening unit further comprises two further rotary body 3 and 4. The rotary body 3 is in the embodiment, a transfer roller and the rotary body 4, an applicator roll, the fluid on the Printing form cylinder 5 transmits.

The axes of rotation of the rotary bodies 2, 3 and 4 of the dampening unit and of the printing forme cylinder 5 as a further rotary body are denoted by R.

The printing form cylinder 5 may have a printing width of, for example, four or six newspaper pages and on its outer circumference corresponding to axially next to each other carry four or six printed images, namely one printed image per newspaper page. The printing form cylinder 5 can have a so-called single or double or even larger circumference, wherein simply and twice in this context mean that the circumference of the printing form cylinder substantially corresponds to the circumferentially measured length of a single printed image or the added length of two printed images, in the embodiment the height of a newspaper page or two newspaper pages. The rotary bodies 2, 3 and 4 each have a smaller circumference than the printing forme cylinder 5. The rotary bodies 2 and 4 are equal in circumference, and the rotary body 3 has a smaller circumference than the rotary bodies 2 and 4. The circumferences of those rotary bodies 2 to 5 , which each form a transmission gap for the fluid, differ in pairs by a non-integer factor,

Along the rotation body 2, a plurality of the discharge devices 1 are arranged axially spaced from each other so that they can apply the fluid over the entire, the transmission of the fluid serving length of the rotating body 2, preferably evenly. In the exemplary embodiment, two dispensing devices 1 are provided for each printed image. In the case of a printing forme cylinder 5, for example, four pages wide, the dampening unit thus comprises eight delivery devices 1 axially next to one another, and in the case of a printing forme cylinder 5, for example six pages wide, it has twelve delivery devices 1 next to each other.

The printing form cylinder 5 is also associated with an unillustrated transfer cylinder, which receives from the printing form cylinder 5 fluid and color corresponding to the printed images of the plate cylinder 5. The transfer cylinder transfers the color according to the image to a printing material to be printed, in the exemplary embodiment, a paper web. He forms with a arranged on the other side of the web just such a transfer cylinder or with a non-printing impression cylinder a printing gap for a two-sided or only one-sided pressure on the continuous printing material.

In printing operation, the dispensing device 1 and give the other dispensing devices 1 fluid according to the need for the rotary body 2 from, in the embodiment by spraying. The rotary body 2 releases a part of the fluid wetting its outer peripheral surface in a transfer nip N ₁ formed with the rotary body 3. The rotary body 3 transfers fluid in a transmission gap N ₂ formed with the rotary body 4 onto the rotary body 4, and this transfers fluid into a transfer nip N _{3 formed} on the printing form cylinder 5 onto the printing forme cylinder 5. The fluid, in the exemplary embodiment dampening solution, occupies the printed images of the plate cylinder 5, the fluid receiving points and prevents so that these locations can be covered with paint. In the direction of rotation of the printing forme cylinder 5, an inking unit is arranged downwards from the dampening unit 1-4, which transfers ink to the printing form cylinder 5. Fluid is not only transported by the rotary body 2 in the direction of the printing form cylinder 5, but by splitting in the opposite direction. In the respective transfer nip N ₁ , N ₂ or N ₃ takes place a film splitting with a back and forth transfer of fluid.

The dispenser 1 discharges the fluid intermittently in fluid pulses. The duration of each pulse is adjustable, d. H. changeable by means of a control. The dispenser 1 operates with a constant period, in each of which a single pulse is delivered. The period duration can be, for example, 100 msec and the pulse duration between 0 and, for example, 20 msec. Within one period, the pulse may be shifted, preferably the time of the beginning of the pulse in each period is selectable independently of the beginning of the pulse of the preceding period. In principle, it is also conceivable that the period is set according to the fluid requirement, d. H. is changed, with either constant pulse duration or constant pulse spacing or by changing these two parameters.

The fluid requirement of the printing unit, to which the printing form cylinder 5 and the dampening unit 1-4 belong, can be taken from the so-called wet curve, the context between the machine speed and thus the rotational speed of the plate cylinder 5 and the required amount of fluid at the respective engine speed.

A corresponding delivery of fluid, which also ensures a uniform occupancy of the printing forme cylinder 5 with fluid is ensured by simulating the behavior of the dampening unit 1-4 and the plate cylinder 5 in a mathematical model The pulse duration and the pulse spacing of the dispenser 1 and each Another dispensing device 1 of the dampening unit 1-4 are set in dependence on a determined in the model topographic fluid occupancy of the plate cylinder 5. The determined in the simulation of fluid occupancy can be compared with a target occupancy, for example, a uniform target occupancy and set the pulse duration in dependence on the result of the comparison. Instead of specifying a target assignment, in an alternative embodiment, only the fluid usage determined in the simulation is used for a comparison and the adjustment of the fluid application. In this case, an absolute minimum or a plurality of local minimums of fluid occupancy is determined and the fluid is deliberately applied in the minimum or the minimum.

The model "runs" in real-time during the entire printing process, even in phases of acceleration or deceleration, parallel to the printing process.

In the model, the outer peripheral surface of each of the rotary bodies 2 to 5 is divided into axially straight lines Z _i which follow each other in the circumferential direction and each have the same width, for example 1 mm measured in the circumferential direction of the respective rotary body 2, 3, 4 or 5. In FIG. 1 this topography is indicated for the rotation bodies 2 to 5. Each of the rotary bodies 2 to 5 is thus divided into rows Z _{i of} equal width. The outer peripheral surface of each of the rotary bodies 2 to 5 is further divided into columns S _j which extend in the circumferential direction, follow each other axially and each have the same axial width. The lines Z _i and columns S _j form a surface grid with grid locations G _ij . In each case one of the dispensing devices 1 is associated with exactly one of the columns S _j , in that each of the dispensing devices 1 faces its associated column S _j . The number of columns S _j is equal for each of the rotary body 2 to 5 equal to the number of axially offset from each other dispensing devices. 1

In the model, the rotational movements of the rotary bodies 2 to 5 are simulated according to the actual machine speed. In the simulation, in each case the same transfer nip N ₁ , N ₂ or N ₃ , one of the lines Z _i of one of the rotational bodies forming the transfer nip passes into overlap with one of the lines Z _i of the other rotational body forming the respective transfer nip. The model calculates the area occupation on the modeled topography of the peripheral surface of the respective rotational body at least once for each of the rotational bodies 2 to 5 during each rotation of the plate cylinder 5 or of the smallest rotational body, preferably during each period of the dispenser 1. This topographical area occupation corresponds to the local distribution of the fluid, ie for each location of the circumferential area it contains the information about the local film thickness on the respective rotational body 2, 3, 4 or 5.

As an alternative to the exemplary embodiment, the peripheral surfaces of the rotary bodies 2 to 5 could also be subdivided only into the rows Z _i , ie only in the circumferential direction. The rows Z _i would extend continuously over the entire wetted with fluid peripheral surface of the respective rotary body 2, 3, 4 or 5 in the axial direction. The film thickness would vary in such a simplified model line by line only in the circumferential direction and would be constant in the axial direction of the respective peripheral surface. However, more preferably, the film thickness can also be varied axially, at least from print image to print image of the plate cylinder 5. More preferably, it can also be axially varied within each printed image by a plurality of dispensing devices 1 are arranged axially adjacent to each print image and can independently release fluid.

FIG. 2 shows the arrangement of the rotary body 2 to 5 as in FIG. 1 , Furthermore, an associated table, namely a table 12 for the rotary body 2, a table 1.3 for the rotary body 3, a table 14 for the rotary body 4 and a table 15 for the rotary body or forme cylinder 5 are shown per rotary body 2 to 5. Tables 12 to 15 each consist of rows Z _i in one of the number of Rows Z _{i of} the respectively associated rotary body 2, 3, 4 or 5 corresponding number and columns S _j , exactly one column per dispenser 1. The rows Z _i of Tables 12 to 15 are continuously in the direction of rotation of the respectively associated rotary body 2, 3, The tables 12 to 15 each contain, in their table _locations corresponding to the grid positions G _ij , a table value T _ij which represents the film thickness on the respective grid position G _{ij of} the peripheral surface of the associated rotary body 2, 3, 4 or 5. This may be the amount of fluid present on the grid site, directly the film thickness, or another equivalent film thickness. Each table value is assigned a specific location on the perimeter area by the respective table. Table 12 thus represents the topographical area occupancy of the rotating body 2 and the tables 13 to 14 correspondingly represent the topographical area occupancy of the rotating body 3, the rotating body 4 and the rotating body 5.

The model is implemented in the exemplary embodiment in a data processing device of the printing press as a table call. Tables 12 to 15 metaphorically lap in simulation, ie, Table 12 on Table 13, Table 13 on Table 14, and Table 14 on Table 15, substituting either rows Z _i of Tables 12 to 15 are shifted in accordance with the rotational speed and the direction of rotation of each associated rotational body within the table, as indicated by a respective loop arrow for each of the tables 12 to 15. Alternatively, the rows Z _i within the tables 12 to 15 can keep their places and one pointer per table can pass through the rows Z _i . In any case, according to the rotational speed and the rotational direction of the rotary body 2 to 5, the fluid transfer in the transfer nips N ₁ to N ₃ is simulated according to the film splitting. The fluid transfer is indicated by arrows, which are also denoted by N ₁ , N ₂ and N ₃ , for the table transmission. The film-splitting effect on which the fluid transfer is based is simulated by forming the arithmetic mean of the film thicknesses of the lines Z _{i of} the contra-rotating peripheral surfaces just in the nip N ₁ , N ₂ or N ₃ as they enter the nip exhibit. In the model, the table values T _{ij of} the currently overlapped lines Z _{i are added} in each of the columns S _j , and the sum is half each on the two lines Z _{i of} the graphically contiguous tables 12 and 13, 13 and 14, Split 14 and 15. It In each calculation step in which the fluid transfer in the individual transfer gaps S ₁ to S _{3 is} determined, the instantaneous area occupancy of all rotational bodies 2 to 5 results.

For the rotation body 2, to which the fluid is discharged directly, the table values T _ij are compared with one another within each of its columns S _{j in} order to determine an absolute minimum or a plurality of local minimums of the film thickness equivalent per column S _j .

FIG. 3 1 shows a schematic illustration of a controller 11 and a data processing device 10 coupled thereto for the plurality of dispensing devices 1. In the data processing device 10, the spreadsheet with its tables 12 to 15 is implemented by programming. The controller 11 controls the dispensers 1 so that targeted fluid is applied to the location of the absolute absolute minimum in the circumferential direction or the respective local minimum. The minimum or the minima is or are determined by the data processing device 10. As seen in the circumferential direction, the location of the job is determined by varying the time of beginning of the pulse within the respective time interval.

In a memory 16 of the data processing device 10, a desired value for the ratio "pulse duration / length of a time interval" is stored for the dispensing device 1. The time interval is the period of time within which the dispenser 1 emits exactly one pulse of the fluid. In the memory 16, a separate desired value is stored in the same way for the other dispensing devices 1. The setpoints can be different or the same. In a simple embodiment, only the same desired value can be provided for all dispensing devices 1 from the outset. However, a separate set point specification per delivery device or print image allows a more flexible coordination of the fluid application to the local requirement. The desired value is preferably predefined as a function of the machine speed, for example as a step function in the form of a number of desired values, which are respectively constant within certain speed ranges and increase with the speed. The setpoint corresponds to the amount of fluid to be dispensed per time interval. The controller 11 can precisely control the dispensing devices 1 in accordance with the respective setpoint value, ie, maintain the pulse duration per time interval, or if this is not the case possible or not desired to control the setpoint before or after, so that the setpoint is set only in the middle after several consecutive time intervals or the mean approaches the exact setpoint without exactly meeting it.

Alternatively or in addition to the setpoint specification described above, for example, a nominal assignment can be stored for the printing form cylinder 5. The data processing device 10 then determined by a target / actual comparison of the target occupancy with the determined in each calculation step or even at larger intervals actual occupancy, which is represented by the tables 12 to 15, the dispensed by the dispenser 1 amount of fluid to be dispensed Fluid quantity is the controller 11 abandoned, which forms therefrom a control signal for the dispenser 1, with which the pulse duration of the dispenser 1 is set according to the amount of fluid to be dispensed.

Reference numerals:

1

delivery device

2

Rotary body, distributor roller

3

Rotary body, transfer roller

4

Rotary body, applicator roll

5

Rotational body, forme cylinder

6-9

-

10

Data processing device

11

control

12

table

13

table

14

table

15

table

16

Storage

N _1,2,3

transfer nip

R

axis of rotation

S _j

Column of the peripheral surface

Z _i

Row of peripheral surface

G _ij

Grid location of the peripheral surface

T _ij

Table value, film thickness equivalent

Claims (19)

1. A method for applying a fluid, namely a dampening agent or an ink, to a rotation body of a printing machine, wherein:

   a) the fluid is applied in pulses while the rotation body (2, 3, 4, 5) is rotating;

   b) a topographical fluid coverage of the rotating rotation body (2, 3, 4, 5) in terms of area coverage and film thickness equivalent is simulated in a model;

   c) and a duration of a next pulse or an interval between consecutive pulses is/are set in accordance with the simulated fluid coverage.
2. The method according to claim 1, wherein the rotation body (2, 3, 4, 5) and another rotation body (2, 3, 4, 5) form a gap via which the fluid is transferred by film splitting, and the topographical fluid coverage is simulated in the model for each of the rotation bodies (2, 3, 4, 5), taking into account the film splitting.
3. The method according to any one of the preceding claims, wherein an outer circumferential area of the rotation body (2, 3, 4, 5) is sub-divided in the model into lines (Z_i) which are consecutive in the circumferential direction, and the fluid coverage is ascertained line by line.
4. The method according to a combination of the preceding two claims, wherein the rotational movement of the rotation body (2, 3, 4, 5) is simulated in the model, and the fluid coverage of the lines (Z_i) which respectively oppose each other in the gap is simulated in accordance with the film splitting.
5. The method according to the preceding claim, wherein the area coverages of the lines (Z_i) which respectively oppose each other in the gap are summed, and the sum thus obtained is divided among these lines (Z_i) as a respectively new fluid coverage, in a ratio in accordance with the film splitting, preferably in equal parts.
6. A method according to any one of the preceding claims and at least one of the following features:

   - the fluid coverage is simulated by means of a spreadsheet;

   - a table (12, 13, 14, 15) for the rotation body (2, 3, 4, 5) is constructed in the model and comprises lines (Z_i) which correspond to the lines (Z_i) of the rotation body (2, 3, 4, 5) according to claim 3, wherein the lines (Z_i) of the table (12, 13, 14, 15) respectively contain at least one tabular value (T_ij) for the film thickness equivalent of the respectively assigned line (Z_i) or of a portion of the respectively assigned line (Z_i) of the rotation body (2, 3, 4, 5).
7. A method according to any one of the preceding claims and at least one of the following features:

   - the fluid is sprayed on;

   - the fluid is sprayed on using a plurality of nozzles which are arranged axially next to each other.
8. The method according to any one of the preceding claims, wherein an outer circumferential area of the rotation body (2, 3, 4, 5) is sub-divided in the model into columns (S_j) which are arranged axially next to each other and extend in the circumferential direction, and the fluid coverage is ascertained column by column.
9. A method according to the preceding claim and at least one of the following features:

   - the fluid is sprayed on using a plurality of nozzles which are arranged axially next to each other, each of the nozzles is assigned at least one of the columns (S_j) onto which the respective nozzle sprays fluid, and the nozzles dispense the fluid in accordance with the fluid coverage of the at least one respectively assigned column (S_j);

   - a table (12, 13, 14, 15) for the rotation body (2, 3, 4, 5) is constructed in the model and comprises columns (S_j) which correspond to the columns (S_j) of the rotation body (2, 3, 4, 5), and the columns (S_j) of the table (12, 13, 14, 15) respectively contain at least one tabular value (T_ij) for the film thickness equivalent of the respectively assigned column (S_j) or of a circumferential portion of the respectively assigned column (S_j) of the rotation body (2, 3, 4, 5).
10. The method according to any one of the preceding claims, wherein the fluid is applied in chronologically consecutive time intervals in respectively one pulse of a pulse duration per time interval, and at least one of the pulse duration and the length of the respective time interval is altered, preferably the pulse duration only.
11. A method according to the preceding claim and at least one of the following features:

    - the pulse duration is varied, preferably with the length of the time interval remaining constant, or the length of the time interval is varied, preferably with the pulse duration remaining constant, so as to adhere to a predetermined target value;

    - the fluid is applied over a plurality of consecutive time intervals, ahead of or lagging behind a predetermined target value for the pulse duration or the length of the time interval, so as to adhere to the target value;

    - the fluid is applied over a plurality of consecutive time intervals only as an arithmetic mean, by varying the pulse duration or the length of the time intervals, so as to adhere to a predetermined target value;

    - a target value is predetermined as a pulse duration per time interval, preferably in accordance with the machine speed;

    - a fluid coverage for a printing form cylinder (5), to which the rotation body (2, 3, 4) transports fluid or which the rotation body forms, is predetermined in the model and compared with the fluid coverage ascertained for the printing form cylinder (5) by the simulation, and the pulse duration or pulse interval is/are set in accordance with the result of the comparison.
12. The method according to any one of the preceding claims, wherein the values (T_ij) ascertained for the local film thickness equivalent by simulation are compared with each other, one or more minima of the film thickness equivalent is/are determined by means of the comparison, and the pulse interval or the pulse duration is/are selected such that the fluid is applied in the one or more minima in a targeted way.
13. The method according to any one of the preceding claims, wherein:

    a) the rotation body (2, 3, 4, 5) is a printing form cylinder (5) or transports fluid to a printing form cylinder (5);

    b) a local distribution of the fluid which is taken up per revolution of the printing form cylinder (5) by a printing material to be printed on is predetermined in relation to the circumferential direction of the printing form cylinder (5) in the model;

    c) and the fluid coverage is simulated in the model in accordance with the predetermined distribution.
14. A device for applying a fluid, namely a dampening agent or an ink, to a rotation body of a printing machine, said device comprising:

    a) a dispensing means (1) for intermittently dispensing the fluid in pulses;

    b) a rotation body (2, 3, 4, 5) which can be rotated about a rotational axis (R), for transferring the fluid received from the dispensing means (1);

    c) a data processing means (10) comprising a model for simulating a topographical fluid coverage of the rotating rotation body (2, 3, 4, 5) in terms of area coverage and film thickness equivalent;

    d) and a controller (11) for the dispensing means (1), which is coupled to the data processing means (10) and by means of which a duration of the pulses or an interval between consecutive pulses can be set,

    e) wherein the controller (11) sets the pulse duration or the pulse interval in accordance with the fluid coverage ascertained by the simulation.
15. A device according to the preceding claim and at least one of the following features:

    - the dispensing means (1) dispenses the fluid in a non-contact way;

    - the dispensing means (1) is a spray nozzle;

    - a plurality of dispensing means (1) are provided and arranged axially offset with respect to each other along the length of the rotation body (2, 3, 4, 5);

    - the rotation body (2, 3, 4, 5) is assigned to a printing form cylinder (5) in order to transport the fluid to the printing form cylinder (5), or forms the printing form cylinder (5).
16. A device according to any one of the preceding claims and at least one of the following features:

    - an outer circumferential area of the rotation body (2, 3, 4, 5) is sub-divided into lines (Z_i) which are consecutive in the circumferential direction, and at least one storage space is provided per line (Z_i) in a memory of the data processing means (10) for a value (T_ij) of the film thickness equivalent of the respective line (Z_i) or of a portion of the respective line (Z_i);

    - an outer circumferential area of the rotation body (2, 3, 4, 5) is sub-divided into lines (Z_i) in the circumferential direction, the model is implemented in the data processing means (10) as a spreadsheet, and a table (12, 13, 14, 15) of the spreadsheet comprises at least one tabular space for each of the lines (Z_i) for a tabular value (T_ij) for the film thickness equivalent of the respective line (Z_i) or of a portion of the respective line (Z_i).
17. The device according to the preceding claim, characterised in that the outer circumferential area of the rotation body (2, 3, 4, 5) is sub-divided axially into columns (S_j) which together with the lines (Z_i) on the circumferential area form a grid comprising grid spaces (Z_i, S_j), and in that the table (12, 13, 14, 15) comprises tabular spaces comprising tabular values (T_ij) for the film thickness equivalent at the respective grid space.
18. The device according to any one of the preceding claims, characterised in that the dispensing means (1) dispenses the fluid in chronologically consecutive time intervals in respectively one pulse of a pulse duration per time interval, a target value for the pulse duration or the length of the time intervals is stored as a target value in a memory (16) of the data processing means (10), and the dispensing means (1) is controlled by the controller (11) such that the dispensing means (1) dispenses an amount of the fluid corresponding to the target value, only in a cumulation over a plurality of consecutive time intervals, by varying the pulse duration or the length of the time intervals.
19. The device according to any one of the preceding claims, characterised in that:

    (i) the rotation body (2, 3, 4, 5) is assigned to a printing form cylinder (5) in order to transport the fluid to the printing form cylinder (5), or forms the printing form cylinder (5);

    (ii) an outer circumferential area of the printing form cylinder (5) is sub-divided into lines (Z_i) in the circumferential direction;

    (iii) at least one target value is stored for each of the lines (Z_i) of the printing form cylinder (5) in a memory (16) of the data processing means (10) for an amount of fluid of the respective line (Z_i) or the amount of fluid to be transferred in the respective line (Z_i) onto a printing material to be printed on;

    (iv) and the dispensing means (1) is controlled by the controller (11) such that the printing form cylinder (5) comprises the target amount in its lines (Z_i) or such that the amount of fluid to be transferred onto the printing material (B) is transferred onto the lines (Z_i) of the printing form cylinder (5).

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