EP0415881B1 - Combination rotary printing machine, particularly for printing securities - Google Patents

Abstract

The rotary web-fed printing machine has three successively arranged printing units, namely one offset and two intaglio printing units which are all of a similar design to sheet-fed printing units and in which the cylinders (2, 3) forming the printing nip have a plurality of sectors separated by cylinder pits (2a, 3b). Each printing unit has, in front of the printing nip, a first paper-web store (29) and an intermittently controllable first draw-roller unit (30) and, after the printing nip, an intermittently controllable second draw-roller unit (31) and second paper-web store (32), the draw-roller units (30, 31) which have only one suction roller being controllable for the forward and backward movement of the web (P) by means of individually regulated drives (30a, 31a) and at the same time serving for the register check. In front of the first paper-web store (29) of the first printing unit (A), between the printing units within the portions limited by the respective paper-web stores and behind the second paper-web store of the last printing unit, the web (P) is moved uniformly by continuously driven draw-roller arrangements (27), whereas during the run through the printing nip the paper-web transport takes place in the pilgrim-step mode.

Description

The invention relates to a combined rotary web printing machine, in particular for printing notes, according to the preamble of claim 1.

From DE-C-31 35 696 a printing unit for a web-fed rotary printing press has become known which allows printing on a web with changeable, adjoining formats and works with four pulling roller groups, the first and the second pulling roller group in front of the printing nip and in between the one Web-tensioning web storage and after the printing nip the third and fourth draw roller group and in between also a web storage are installed; the second and third draw roller groups are each controlled by a regulated electric motor drive for moving the web forward and backward. As long as the beautiful and Working against pressure, sector-shaped rubber cylinders on the paper web, this is transported by the rubber cylinders; if, on the other hand, the cylinder pits lying between the sectors pass through the pressure nip, the mentioned controlled draw roller groups take over the further transport, which therefore takes place in the manner of a pilgrim step operation or a so-called stop-and-go operation with adjustable repeat length. This known printing unit is an offset printing unit, and in the event that the paper web is subsequently to receive further prints, it is expressly mentioned in the aforementioned DE-C 31 35 696 that one or more downstream printing units or processing stations are then provided are which further process the paper web running at a uniform speed.

Combined web printing presses with uniform paper web transport are also known, for example, from EP-B-0 132 857; they allow notes of value, in particular banknotes, to be produced in one operation with a security background which can be produced by an indirect printing process such as the offset printing process and with a main pattern produced by intaglio printing. Here, as is customary in web-fed printing machines, the paper web is always transported continuously at a speed which is equal to the peripheral speed of the cylinders of the printing units forming a printing nip, since the paper web is constantly clamped between these two cylinders.

For this reason, in known web printing machines with several printing units arranged one behind the other, there is the difficulty that tolerances and register errors in the transport direction of the web add up when the paper web is transported from the first printing unit to the following printing units. The behavior of the paper, which changes depending on the ambient conditions, in particular when passing through ink drying devices between two printing units and as a result of moistening after drying, contributes in particular to these register errors. The only way to correct the register is to change the paper web tension, but this is naturally only possible within narrow limits, which are often not sufficient to achieve perfect register control.

Furthermore, setting up previous web printing machines with multiple printing units is difficult and time-consuming. This applies in particular if there is an indirect printing unit and an intaglio printing unit because then the diameters of the cylinders of both printing units are adjusted taking into account the different conveying behavior of the paper web, which in the indirect printing unit is subject to a comparatively low contact pressure, but in the intaglio printing unit is subject to a strong contact pressure Need to become.

Another difficulty with web printing machines with continuous paper web transport is that the cylinders forming the printing nip, i.e. the blanket cylinders in an indirectly printing printing unit and the plate cylinder and the printing cylinder in an intaglio printing unit, have to be provided with a continuous surface and that their circumferential length is a multiple of that The length of a benefit, i.e. a security print, must be if no paper losses are to occur. These requirements mean a considerable effort for the production of the cylinders mentioned, compared with the cylinders used in sheet-fed printing machines, which are sector-shaped and in which individual blankets, printing plates or printing covers can be clamped onto the individual cylinder sectors in a relatively simple manner.

The production of a plate cylinder of a web printing machine for intaglio printing is particularly labor-intensive, since it is difficult to fix the printing plates seamlessly on the cylinder jacket and to ensure that the cylinder jacket has a perfect concentricity and its outside diameter is constant over the entire cylinder length, so that a perfect register is achieved. In addition, the manufacture of the cylinder jacket requires an extremely precise machining, since its inner circumference must be slightly conical so that it is precisely adapted to the conical shape of the corresponding printing press shaft on which it is fastened for printing. This means high manufacturing costs for the cylinder jacket. The rather complicated manufacture of the plate cylinder of a web printing machine for intaglio printing is described for example in EP-B 0 211 450.

These difficulties are eliminated with a sheet-fed printing press, since in the case of intaglio printing, the individual printing plates can be individually attached, tensioned, adjusted and replaced on the sectors of the plate cylinder, and in the same way the printing cylinder can be provided with tried-and-tested printing covers with a long service life instead of in a complex manner to be covered with a continuous layer of material, which does not have the same print quality as the print covers on a sheetfed press and also has a shorter lifespan.

These advantages of a sheet-fed printing press are used in the known offset printing unit according to DE-C-31 35 696 for web printing, but there is no suggestion in this document for solving the other problems explained above, which include those in combined web printing machines with several printing units In particular, intaglio printing units can also occur.

The present invention has for its object to provide a combined web printing machine according to the preamble of claim 1, which on the one hand enables easy, flawless register correction and print length correction and on the other hand eliminates the difficulties associated with the production of cylinders with a continuous surface .

According to the invention, this object is achieved by the features specified in the characterizing part of claim 1.

In the combined web printing machine according to the invention, all the advantages known from sheet-fed printing machines can thus be exploited and, furthermore, individual register corrections can be carried out for each printing unit, so that a summation of register errors is eliminated. The advantages are discussed in more detail at the end of the description of FIGS. 1 to 3.

Preferably, the web printing machine according to the invention, as stated in claim 2 or 3, has an indirectly printing printing unit, which is expediently the first printing unit, and at least one, in particular two, intaglio printing units; their construction with sector-shaped printing and plate cylinders is very advantageous, as explained earlier. The order of the printing units can also be selected according to claim 4.

The tension roller groups known from DE-C 31 35 696 each consist of a tension roller and a pressure roller pressing the paper web against it. For the pilgrim step operation, however, such a pull roller group is unfavorable, since the masses of two rollers have to be braked and accelerated very quickly and, in addition, in order to prevent the paper web from sliding between the rollers, both rollers have to be pressed against one another with great force. In order to avoid these disadvantages, the web printing machine according to the invention preferably has a draw roller unit in the form of only one suction roller, as described in claim 5; expedient configurations of this suction roll are described in the following dependent claims.

A pulling roller designed as a suction roller is known from GB-A-1.206.710, but is preferably used for the transport of photographic films. As a pulling roller in web-fed printing presses, in which the paper web is transported in a pilgrim step, i.e. with rapidly changing speeds and therefore high accelerations, a Welze that only works with suction has not been considered.

Expedient designs of the cylinders of a printing group forming the printing nip result from claims 11 and 12. The regulating and control system for the two drawing roller units of a printing group is preferably constructed as specified in claims 13 and 14.

• Figuren 1 bis 3, von links nach rechts aneinandergelegt, eine kombinierte Rollendruckmaschine nach der Erfindung, wobei Figur 2 das erste indirekt druckende Druckwerk und die Figuren 3 und 1 zwei nachgeschaltete Stichtiefdruckwerke darstellen,
• Figur 4 den Axialschnitt durch eine Saugwalze einer Zugwalzeneinheit, gemäss der Linie IV-IV nach Figur 6,
• Figur 5 eine teilweise geschnittene Teilansicht in Richtung des Pfeils V nach Figur 4,
• Figur 6 einen Radialschnitt der Saugwalze gemäss der Linie VI-VI nach Figur 4, in vergrössertem Massstab,
• Figur 7 einen Schnitt durch den Saugwalzenmantel,
• Figur 8 einen Teil der in einer Ebene abgewickelten Oberfläche des Saugwalzenmantels mit der Verteilung der Saugöffnungen,
• Figur 9 einen vergrösserten Schnitt durch den Saugwalzenmantel an der Stelle IX nach Figur 7 zur Veranschaulichung der Form einer Saugöffnung,
• Figur 10 eine teilweise Darstellung eines Druckzylinders eines der Stichtiefdruckwerke im Bereich der Zylindergrube und
• Figur 11 ein Signalflussbild der Regelung und Steuerung der beiden Zugwalzeneinheiten eines Druckwerks.

The invention is explained in more detail with reference to the drawings using an exemplary embodiment. Show it:

• 1 to 3, placed from left to right, a combined web printing press according to the invention, FIG. 2 showing the first indirectly printing unit and FIGS. 3 and 1 representing two downstream intaglio printing units,
• FIG. 4 shows the axial section through a suction roller of a pull roller unit, according to line IV-IV according to FIG. 6,
• FIG. 5 shows a partially sectioned view in the direction of arrow V according to FIG. 4,
• FIG. 6 shows a radial section of the suction roll according to line VI-VI according to FIG. 4, on an enlarged scale,
• FIG. 7 shows a section through the suction roll jacket,
• FIG. 8 shows part of the surface of the suction roll shell developed in one plane with the distribution of the suction openings,
• FIG. 9 shows an enlarged section through the suction roll jacket at point IX according to FIG. 7 to illustrate the shape of a suction opening,
• FIG. 10 shows a partial illustration of a printing cylinder of one of the intaglio printing units in the area of the cylinder pit and
• Figure 11 is a signal flow diagram of the regulation and control of the two drawing roller units of a printing unit.

The general structure of the combined printing press with the three printing units A, B and C and then the transport device for the paper web and its course are described below.

The combined printing press shown in Figures 1 to 3 has three printing units A, B and C, which are successively traversed by the web P to be printed in the direction of the arrows. The first printing operation takes place in the indirectly printing printing unit A (FIG. 2), which is located in the middle of the machine and which, in the example under consideration, is a multicolor offset printing unit that works in perfect and reverse printing. Here, both sides of the web are provided with multicolored offset printing at the same time. The web then runs through an intaglio printing unit B (FIG. 3) arranged at the right end of the machine, in which one side of the web receives a multicolor intaglio printing. Finally, the web runs through a further intaglio printing unit C arranged at the left end of the machine, in which the other side of the web receives a multicolor intaglio printing.

The printing unit A, designed as an offset printing unit, has two interacting rubber cylinders 2 and 3, which are mounted next to one another in a frame 1 and rotate in the direction of the curved arrows, each with three sectors, on each of which a rubber blanket 2a or 3a is stretched. The sectors are separated by cylinder pits 2b and 3b, in which the means for tensioning the rubber blankets are subordinate. This offset printing press is therefore designed similarly to a sheet-fed printing press.

Each blanket cylinder 2 and 3 works with four plate cylinders 4 and 5, which are mounted in the frame 1 and which carry offset printing plates and are colored in different colors by corresponding inking units 6 and 7, respectively. In the example considered, the top inking unit has a simple ink fountain on each side, while the other three inking units are equipped with a double ink fountain on each side. As the dampening units assigned to each inking unit indicated in FIG. 2 show, the example under consideration is a wet offset printing press which can alternatively also be operated as an indirect high-pressure unit or in a combination of both methods. All inking units 6 on one side are arranged in a removable inking unit frame 8 and all inking units 7 on the other side in a removable inking unit frame 9. In addition, automatic blanket washers 10 and 11 are installed on the circumference of the blanket cylinders 2 and 3, which are moved away from the blanket cylinders during the printing operation of the machine. A paper drying device 12, which works with UV radiation and through which the freshly printed web runs, is installed above the rubber cylinders 2 and 3.

The intaglio printing unit B (FIG. 3) has a plate cylinder 14 which is mounted in a frame 13 and a printing cylinder 15 which cooperates with it. This intaglio printing press is also designed similarly to a sheet-fed printing press, that is to say the plate cylinder 14 has sectors separated by cylinder pits 14b, on which three Pressure plates 14a are clamped by means of devices installed in the cylinder pits 14b. Correspondingly, the pressure cylinder 15 has three sectors, separated by cylinder pits 15b, on which pressure covers 15a are stretched. The plate cylinder 14 is inked indirectly on the one hand by a collecting and inking cylinder 16 and on the other hand directly by a stencil roller 19. In the example considered, the collecting and inking cylinder 16 works with three ink selection rollers 17, which are inked by an inking unit 18 each. These color selection rollers 17 are designed like stencil rollers and have relief-like zones, the contours of which correspond to the outlines of the areas to be printed with the relevant color. The different ink areas originating from all three ink selection rollers 17 are collected on the collecting and inking cylinder 16 and transferred to the printing plates 14a. The stencil roller 19, which is seen behind the collecting and inking cylinder 16 in the direction of rotation of the plate cylinder 14, is inked by an inking unit 20. Behind this stencil roller 19, a pre-wiping device 22 engaging the plate cylinder 14 and then a wiping device 23 are installed. The cylinders 14, 15 and 16, whose direction of rotation is indicated by curved arrows, the stencil roller 19, the pre-wiping device 22 and the wiping device 23 are installed in a machine frame 13, while the ink selection rollers 17 with their inking units 18 and the inking unit 20 in a removable inking unit frame 21 are arranged, the removed position is indicated by dashed lines.

The intaglio printing unit B explained above is known and is described in EP-B 091 709 by the same applicant.

The web P printed on one side in the printing unit B is then printed on the other side with a multicolour intaglio printing image in the third printing unit C, which is also an intaglio printing unit that is constructed in mirror image of the printing unit B. Because of the same structure of the printing units B and C, the parts of the printing unit C are denoted by the same reference numerals 13 'to 23', however, with a dash, so that a description of the printing unit C is dispensed with.

All three printing units A, B and C and the transport device for the web P described below are accommodated in a common main frame 24 of the machine. The transport device and the course of the path P are described below, only the parts essential for understanding the invention being described.

The web P is unwound from a supply roll, not shown, and passes via a web feed device 25 (FIG. 2) and a turning bar 26 into a first draw roller arrangement 27, consisting of a draw roller which is wrapped by the web, and a pressure roller which counteracts the web the pull roller presses. This tension roller arrangement 27 and the tension roller arrangements 34 (FIG. 3), 34 ′ (FIG. 1) and 48 (FIG. 3) mentioned later are preferably driven uniformly. Via a device 28 for laterally aligning the web, it then passes over deflection rollers into a first paper web storage 29, which in the example under consideration works with a vacuum chamber. Such a paper web store is known and is controlled in such a way that the paper web P between the draw roller arrangement 27 and the entrance of the paper web store 29 is tensioned taut with a predetermined force by air vacuum and the tension of this section of the web is kept constant at a predeterminable value.

At the exit of the paper web storage 29, the web passes through a drawing roller unit 30, which is individually and intermittently controlled to move the web back and forth. In the example under consideration, this individually controllable pulling roller unit 30 has a single suction roller 30b as the pulling roller, the construction of which will be described in more detail later and which by an individually controlled drive 30a in the form of a electronically controlled motor. The web emerging from the paper web store 29 wraps around this suction roller from below by approximately 180 ° and then, guided by a deflection roller, runs through the pressure gap formed by the two rubber cylinders 2 and 3, then through the drying device 12 and then wraps one to one from above second suction roller unit 31 belonging suction roller 31b again by approximately 180 °. This pulling roller unit 31 installed in a frame part 24a above the main frame 24 is constructed like the pulling roller unit 30, can be controlled intermittently for moving the web forwards and backwards and is in turn moved by an individually controlled drive 31a in the form of an electronically controlled motor. After the drawing roller unit 31, the web passes through a second paper web storage 32, which is constructed and controllable in exactly the same way as the paper web storage 29. The web is then moved over several deflecting rollers, to the right in the illustration according to FIGS. 2 and 3, by a moistening device acting on both sides of the web 52 and a device 33 which adapts the paper path to the desired repeat length are passed to a further pulling roller arrangement 34 which is constructed in the same way as the pulling roller arrangement 27 and has a uniformly driven pulling roller and a pressing roller which presses the web against it (FIG. 3). The roller 34a, over which the web then runs, measures the web tension and controls the device 33 and the tension roller arrangement 34.

The web P then continues via a device 35 measuring its moisture and temperature, a device 36 for laterally aligning the web and via a deflecting roller into a first paper web storage 37 belonging to the second printing unit B, which is so is constructed and controllable like the paper web storage mentioned above. In the area between the paper web stores 32 and 37, the paper web is kept constantly tensioned with an adjustable force and is moved by the draw roller arrangement 34 at a uniform speed.

After exiting from the paper web storage 37, the web loops from above, through approximately 180 °, through which the suction roller 38b of an in turn intermittently controlled drawing roller unit 38, guided by deflection rollers, then wraps around the printing gap between the plate cylinder 14 and the printing cylinder 15 of the engraving printing unit B. , by approximately 180 °, the suction roller 39b of an intermittently controlled pulling roller unit 39 and then arrives in the second paper web storage 40 associated with the printing unit B. The pulling roller units 38 and 39 are designed like those described above and are each controlled by an independent, regulated drive 38a or 39a controlled to move the portion of the web extending between the paper web stores 37 and 40 back and forth. When the suction roller 39b is wrapped around, the side of the web that is not printed in the printing unit B bears against this roller.

After exiting the paper web storage 40, the web passes a video inspection device 41 which scans the printed images and then, after being deflected by a deflection roller, passes through a drying chamber 42 with a plurality of hot air dryers 43 mounted on the main frame 24 Figure 2 left side of the drying chamber 42 and comes into a frame part 24b mounted on the main frame 24, in which it wraps around two driven cooling rollers 44 and a moistening device 45 in between goes through. The web is then guided over deflection rollers above the frame part 24a and further, to the left in the illustration according to FIGS. 2 and 1, up to a moistening device 46 which moistens both sides of the web.

The following stations of the transport device including the passage of the web through the printing nip between the plate cylinder 14 'and the printing cylinder 15' of the intaglio printing unit C correspond to the previously described stations 33 to 45 and the passage of the web through the printing unit B. Therefore, they become the moistening device 46 following stations, which are designated by the corresponding same, but with a dash reference numerals 33 'to 45', not described in detail. It should only be pointed out that, in front of the printing nip of the printing unit C, a first paper web store 37 'and the intermittently controlled suction roller 38'b of a first drawing roller unit 38' and after the printing nip the intermittently controlled suction roller 39'b of a second drawing roller unit 39 'and a second paper web storage 40 'are installed, so that the relevant section of the web in the printing unit C can be moved back and forth by an independent controlled drive 38'a and 39'a. The suction roll 39'b is wrapped by the side of the web not printed in the printing unit C.

After the web P has left the frame part 24'b with the cooling rollers 44 'and the moistening device 45' (FIG. 2), it runs to the right in the illustration according to FIGS. 2 and 3 and is guided by deflection rollers which are attached to supports 47 on the Frame part 24a and mounted on the drying chamber 42, passed into a frame part 24c, in which they between the uniformly driven drawing roller and the Pressure roller of a further tension roller arrangement 48 passes through and another dampening device 49 passes. Then the web, guided by deflection rollers, passes a further video test device 50 to the exit 51 of the machine, from which it is fed to further control and processing stations, in particular the cutting stations.

The transport device described is designed such that the paper web from its paper roll to the first paper web storage 29 of the printing unit A, between the second paper web storage 32 of the printing unit A and the first paper web storage 37 of the printing unit B, between the second paper web storage 40 of the printing unit B and the first paper web storage 37 'of the printing unit C and behind the second paper web storage 40' of the printing unit C is continuously moved, while the sections of the web passing through the printing nips of all three printing units A, B and C between each of the first and second paper web storage units of each printing unit in the so-called pilgrim step - Operation can be moved back and forth in a regulated manner. It is briefly explained for printing unit A (FIG. 2):
As long as the blankets 2a and 3a of the blanket cylinders 2 and 3 act on the web P and pinch it during printing, the web is transported by the two rotating blanket cylinders 2 and 3 and the suction rollers 30b and 31b at the speed of the nip. However, each time two cylinder pits 2b and 3b lie opposite one another and release the web for a correspondingly short period of time, the pull roller units 30 and 31 then take over the further transport of the web alone. During this short phase, the paper web between the two rubber cylinders 2 and 3 becomes normal in a fraction of a second Printing nip speed decelerated to a standstill, then accelerated in the reverse direction, then decelerated again to a standstill and finally accelerated in the forward direction to the printing nip speed, whereupon the further transport again through the two rubber cylinders 2 and 3 and the suction rollers 30b and 31b Printing nip speed occurs as soon as the blankets of the two blanket cylinders following the mentioned cylinder pits again clamp the web on both sides for the following printing. The described pilgrim step movement is controlled in such a way that the printed images successively transferred to the paper web follow one another at a predetermined narrow distance in order to save paper, and allows the printing format to be changed continuously in a manner known per se, for example between the repeat lengths 605 mm measured in the transport direction and 685 mm without having to change the cylinders. It is sufficient to suitably adjust the lengths by which the web is moved back and forth relative to the circumference of the moving rubber cylinders 2 and 3 during the pilgrim step operation and to program the control of the drives 30a and 31a accordingly. In addition, the tension roller units 30, 31 take over the register and print length control, which is explained in more detail with reference to FIG. 11.

FIG. 11 shows the signal flow diagram of the regulating and control system of the two drawing roller units of a printing unit, specifically for example the printing unit A with its two rubber cylinders 2 and 3 as printing unit cylinders and the drawing roller units 30 and 31. Above in FIG. 11 the path of the paper web P is schematically shown the paper web storage 29, via the suction roller 30b, through the pressure gap between the two rubber cylinders 2 and 3, via the suction roller 31b and represented by the paper web storage 32. The suction roller 30b is equipped with an encoder E₀ as an actual value transmitter, which measures the actual position value αi of the suction roller 30b indicated by an arrow, ie its angular position. Likewise, the suction roller 31b is equipped with an encoder E₁ as an actual value transmitter, which measures the actual position value βi of this suction roller. One of the printing unit cylinders, in the example considered, the blanket cylinder 3, is provided with an encoder E as a setpoint generator, which measures the angle of rotation φ of the blanket cylinder 3 and thus, of course, of the blanket cylinder 2 driven synchronously and counter to this. A reader L1 for reading register marks RM, which are provided on the paper web P, for example in the form of watermarks and whose position is designated by x, is installed in front of the printing nip. Behind the printing gap there are two readers L2 and L3, which read printing marks DM, which were applied in the printing unit A at the start and end of the previous print and whose distance represents the actual value of the print length DLi.

According to FIG. 11, the regulating and control system has a pilgrim step generator PS, a controller R connected to its output, for example in the form of a process computer, and two comparators V1 and V2 each provided with four inputs. The comparator V1 is connected on the input side to the three encoders E, Eo and E1 and to the reader L1 and with its output to the controller R. The comparator V2 is also connected on the input side to the three encoders E, Eo and E1 and to the readers L2, L3 and with its output to the controller R. The controller R, which is also connected on the input side to the three encoders E, Eo and E1, has two outputs, each of which is connected to a power actuator LSTG, of which the one controls the draw roller unit 30 and the other controls the draw roller unit 31.

The system described works as follows:
At the inputs Sr and Sd, preferably with the help of a higher-level process computer PR, the desired average repeat length RL is entered into the pilgrim step generator PS and the desired print length DL into the controller R. Repeat length is known to mean the distance from the beginning of printing to the beginning of printing of successive prints. The pilgrim step generator PS calculates the pilgrim step necessary for this repeat length RL. The control of the tension roller units 30, 31 takes place as a function of the angle of rotation φ or the speed of the rubber cylinders 2 and 3, taking into account register and pressure length corrections.

The comparator V1 compares the angle of rotation φ of the rubber cylinders 2, 3 and the position x of the read register marks RM and gives a possible deviation Δx from the ideal position x of the register mark RM on the controller R. The comparator V2 compares the angle of rotation φ of the rubber cylinders 2, 3 and the actual value of the pressure length DLi read by the readers L2, L3 and gives a possibly existing deviation ΔDL from the target value of the pressure length DL to the controller R.

sowie β, β̇,

, also jeweils den Lage-, Geschwindigkeits- und Beschleunigungssollwert der Saugwalzen 30b bzw.31b, als Steuerwerte für die betreffenden Leistungsstellglieder LSTG vor, welche für eine entsprechende Steuerung dieser Saugwalzen sorgen. Dabei wird der Positionssollwert der Papierbahn am Ende des Pilgerschrittbetriebs derart vorgegeben, dass eine eventuelle Abweichung Δx vom idealen Wert der Rapportlänge RL kompensiert wird. Ausserdem wird die Dehnung der Papierbahn vor dem Druckwerk während des Pilgerschrittbetriebs durch entsprechende Regelung der Bahnspannung so gesteuert, dass eine eventuelle Abweichung ΔDL kompensiert und damit die gewünschte Drucklänge DL exakt eingehalten wird. Die jeweilige Dehnung der Papierbahn ergibt sich aus den gemessenen Winkelstellungen und Winkelgeschwindigkeiten der Saugwalzen 30b und 31b und lässt sich durch vorübergehend unterschiedliche Winkelgeschwindigkeiten beider Saugwalzen verändern.Depending on the angle of rotation φ of the rubber cylinders 2, 3, on the actual position values αi, βi of the suction rolls 30b and 31b and on the deviations Δx and ΔDL, the controller R gives the setpoints α, α̇, and

as well as β, β̇,

, ie in each case the setpoint, speed and acceleration setpoint of the suction rolls 30b and 31b, as control values for the power actuators LSTG in question, which ensure appropriate control of these suction rolls. The Position setpoint of the paper web at the end of the pilgrim step operation is specified in such a way that a possible deviation Δx from the ideal value of the repeat length RL is compensated for. In addition, the stretching of the paper web in front of the printing unit during pilgrim step operation is controlled by appropriate regulation of the web tension in such a way that any deviation ΔDL is compensated for and the desired printing length DL is thus exactly maintained. The respective elongation of the paper web results from the measured angular positions and angular velocities of the suction rolls 30b and 31b and can be changed by temporarily different angular speeds of the two suction rolls.

After the pilgrim step operation, both suction rolls 30b and 31b are operated during the printing phase while maintaining the set web stretch with peripheral speed synchronous with the peripheral speed of the rubber cylinders 2, 3.

If the paper web P entering the first printing unit of the printing press, in the example considered printing unit A, has no previously applied register marks or no watermarks acting as register marks, then of course the reader L1 and the comparator V1 are out of operation. The comparator V2 for the print length works as described above. By entering the setpoint value of the repeat length RL at the input Sr, the position setpoint of the paper web at the end of the pilgrim step operation, taking into account the print mark DM marking the start of printing, is specified such that this repeat length RL is exactly adhered to by appropriately dimensioning the control variables for the pulling roller units 30, 31 . In this case, one of the printing marks generated in printing unit A also has DM nor the function of a register mark, with respect to which the repeat length, that is to say the register, is controlled during the immediately following printing in printing unit A.

In all cases, the printing marks applied in the first printing group and marking the start of printing serve in the second printing group and in the following printing groups, in the example considered in printing groups B and C, as register marks, whose position x read in front of the printing nip in the comparator V1 with the angle of rotation φ the cylinder of the printing unit in question is compared in order to determine and correct a possible deviation .DELTA.x.

Instead of providing print marks which are printed by the printing plates on the later-trimmed edge surrounding the print images, sufficient contrasts can also be used between the front boundary of the print image in the direction of transport and the white border and between the rear print image boundary and the white border to generate print mark signals which are used to regulate the print length or the repeat length.

With control and regulating systems of the same design, as described with reference to FIG. 11, the suction rollers 38b and 39b in the intaglio printing unit B and the suction rollers 38b 'and 39b' in the intaglio printing unit C are controlled. Here, the pull roller units 38, 39 and 38 ', 39' also also take on the function of register and print length correction so that the prints in intaglio printing units B and C are held in register with respect to the previously applied prints. The regulation takes place as a function of the printing marks applied in the first printing group A, which function as register marks, and as a function of those in the relevant printing group B or C generated print marks. In these cases, the plate cylinder 14 or 14 'or the pressure cylinder 15 or 15' is provided with an encoder E as a setpoint generator.

Instead of encoders, angle position encoders of another known type can also be used.

The higher-level process computer PR, which is preferably provided for the entire press, coordinates and optimizes the regulating and control systems of each of the printing units A, B and C.

In a further development of the inventive concept, by means of the infinitely variable, computer-controlled change in repeat length, the same or different or constantly changing paper throughput per unit of time through the three different printing units A, B, C of the exemplary embodiment. As a result, the machine can react immediately to all possible influences that disturb the printing operation of a web press without time-consuming and costly changes in the printing and plate cylinder diameters involved. Problems such as web shortening due to drying, web lengthening due to rewetting, different print lengths due to different web tension or extremely different contact pressures with engraving, gravure and offset printing, different paper qualities, watermarks jumping from roll to roll etc. are solved by the decoupling of the different printing units according to the invention by means of computer-controlled, independent pilgrim stepper drives for the paper web.

As a result, it is also possible in an advantageous manner to work in each of the three printing units A, B, C not only with different repeat lengths, but also during the respective printing process with different paper web tensions for the purpose of correcting the printing length.

The previously usual special devices for register correction or printing length correction in combined printing presses are no longer necessary, since their function is taken over by the pull roller units.

Another advantage is that the general previous register problems are avoided, which in particular resulted from the fact that tolerances and register errors added up during the successive printing operations. Such register errors depend above all on the properties and behavior of the paper web, which undergoes changes as a result of drying and moistening. However, these are completely compensated for by the regulated pilgrim step operation in the printing units B and C. In fact, the pilgrim step operation in a printing unit can completely eliminate all register errors that have previously occurred, so that, with regard to register control, each printing operation begins again, so to speak.

The disadvantages of previous combined printing presses with a continuous, uniform paper web transport are also eliminated, in which the coordination of the conveying behavior between an offset printing press and a intaglio printing press and the exact adjustment of the diameters of the offset rubber cylinders and the plate cylinders of the intaglio printing press are very difficult.

In addition, you can use the well-known and well-known methods of fastening, clamping and aligning individual printing plates on the plate cylinder in the intaglio printing units to be used, i.e. the well-known advantages of an intaglio printing machine designed as a sheet-fed printing machine, which eliminates all the complications associated with intaglio printing machines and whose form cylinders are connected, are omitted. As with sheetfed printing, the printing cylinder can also be equipped with well-known and proven printing covers with a long service life, so that the highly noticeable embossing characteristic of intaglio printing is achieved.

Figures 4 to 9 show a preferred embodiment of the suction roller 30b, 31b, 38b, 39b, 38b ', 39b' a pull roller unit 30, 31, 38, 39, 38 ', 39'. According to Figure 4, the rotating part of this suction roller consists of a roller shell 61, which is made of a light carbon fiber reinforced plastic (CFRP), namely made of carbon fiber impregnated with plastic, and therefore has a relatively low rotational inertia. Since the suction roller must be repeatedly braked and accelerated strongly in a fraction of a second during pilgrim step operation, the lowest possible moment of inertia of the rotating part is desirable. In Figure 7, the roll shell 61 is shown as a single part, it typically has an overall axial length of approximately 100 cm and a diameter of approximately 15 cm. The representations according to FIGS. 4 and 7 show how the interruptions indicate that the suction roll is shortened axially.

At one end, an outer ring flange 61a is formed on the cylinder jacket 61, and the other end is tapered to form a connecting flange 61b. On its circumference, the roller shell 61 is provided with a plurality of suction openings 62, the distribution of which will be explained later. A flange part 63, preferably made of light metal, is fastened to the ring flange 61a by means of screws 64.

The roller shell 61 is rotatable about a solid, hollow roller core 65, preferably made of metal. At the end facing the connecting flange 61b of the roll shell 61, a metallic bearing journal 66 is fastened to the roll core 65, the base of which tightly closes the inside of the roll core 65. On the circumference of the roller core 65 at a certain angular distance from one another, in the example considered at an angular distance of 180 °, two radial, preferably metal partitions 69 are fastened, which enclose a suction chamber 72 between them, as shown in particular in FIG. On both axial sides of the partition walls 69, ring walls 67 and 68 are fastened to the circumference of the roller core 65, which preferably also consist of metal and which close the suction chamber 72 on their axial sides. The ring wall 68 at the end of the roller core 65 facing the flange part 63 is axially extended by an outstanding connecting piece 68b, which is used to fasten the stationary part of the suction roller to the machine frame and to connect to a vacuum source. The peripheral wall of the roller core 65 is provided with relatively large passage openings 70 within the suction chamber 72. All parts 66, 67, 68, 69 fastened to the roller core 65 are welded in the example considered.

As shown in Figure 4, the roller shell 61 is at one end with its flange 63 by means of a bearing 71 'in the example considered as a bearing 71' on the socket 68b and at its other end with its connecting flange 61b by means of a bearing 71 also designed as a ball bearing mounted rotatably on the journal 66 of the roller core 65. The arrangement is such that the gaps between the inner circumference of the roller shell 61 and the radially outer ends of the partition walls 69 and the outer circumference of the ring walls 67 and 68 are at least approximately sealed against air passage. In the example under consideration, this takes place by means of a suitable sealing material 73, which is inserted into recesses 69a, which run parallel to the axis, of the radially outer ends of the partition walls 69 and in annular recesses 67a and 68a (FIG. 5) on the circumference of the ring walls 67 and 68. This sealing material 73 can in particular be a self-adhesive brush, for example. However, the arrangement can also be such that only a very small gap is provided between the inner circumference of the roller shell 61 and the partition walls 69 and the ring walls 67 and 68, without the insertion of any special sealing material. Such narrow gaps offer such high resistance to air passage that these gaps are sufficiently tight to maintain the required negative pressure within the suction chamber 72.

In the assembled state, the connecting piece 68b is constantly connected to a vacuum source, so that a sufficiently strong vacuum is maintained inside the roller core 65, by means of the openings 70, in the suction chamber 72 and consequently at the suction openings 62 opening into this suction chamber 72, through which the paper web, which wraps around the suction roller in the area of the suction chamber 72 by 180 °, is pressed against the outer circumference of the roller shell 61, that is to say is held by strong suction. By means of a suitable surface treatment of the roller shell 61, the surface of which is preferably nickel-plated and plasma-coated, as a result of which this surface becomes impact-resistant and abrasion-resistant and is provided with a certain roughness, it is achieved that even with the high accelerations of the suction roller which occur in pilgrim operation, there is no slippage between it and the paper web takes place, which therefore follows all the movements of the suction roll.

In order to achieve an easy and flawless detachment of the paper web from the suction roll at the end of the loop, that is to say at the end of the suction chamber 72, the suction openings 62 are distributed in a certain manner, as shown in FIG. In the illustration according to FIG. 8, which shows part of the roll shell 61 developed in one plane, the suction openings 62 are arranged in zigzag lines lying parallel to one another, that is to say on the roll shell 61 in each case along helical line sections which run in a zigzag shape. In this way, adjacent suction openings 62 are each arranged angularly and offset from one another parallel to the axis direction, the angular displacement in each case being 6 ° in the example under consideration. Viewed in the circumferential direction, successive suction openings are at an angle of 30 ° apart, and the distance between adjacent suction openings along a surface line, that is to say parallel to the axis, is approximately 5 cm in the example considered. On the one hand, this results in a successive cut-off of the negative pressure at the end of the looping, so that the web can easily move away the suction roll releases, and on the other hand, good adhesion of the web to the suction roll is ensured in the entire loop area. The shape of the suction openings 62 is shown in the enlarged illustration according to FIG. 9, according to which the inner region of this suction opening consists of a cylindrical bore and the outer region consists of a conical widening.

A perfect balancing of the roll shell 61 is expediently achieved by making appropriately arranged and dimensioned bores 74 in the conical wall of the connecting flange 61b (FIGS. 4 and 7) and optionally in the ring flange 61a between the openings for the passage of the screws 64. If such bores are not sufficient, small pins can also be glued in on the opposite side to achieve perfect balancing.

The roller jacket 61 is pressed directly onto the shaft of the drive motor with its integrally formed connecting flange 61b.

When printing small formats, these have a greater distance from one another on the rubber cylinders of the offset printing unit or on the plate cylinder of the intaglio printing unit, which then carries correspondingly shorter printing plates in the circumferential direction, than when printing large formats. Accordingly, during the pilgrim step operation, that is to say during the period in which two cylinder pits of the cylinders interacting with one another, a greater web length must be moved relative to the cylinders than when printing large formats. In order therefore to have sufficient time between two successive prints for the pilgrim step operation when printing small formats, the cylinders forming a printing gap are advantageously designed such that the Cylinder pits can be changed in their circumferential length in the case of a printing cylinder by removable and exchangeable filler pieces of different lengths and in the case of a blanket cylinder by appropriately dimensioned rubber blanket pads and adapted to the respective format.

FIG. 10 shows the example of a printing cylinder of an intaglio printing unit, in the example considered the printing cylinder 15, with a metallic filler 54 inserted in the cylinder pit 15b. The pressure cover 53 clamped on the cylinder sector 15a is fastened with its end 53a engaging in the cylinder pit 15b in a known manner to a tensioning shaft 58, by means of which it is tensioned. The other end of the pressure cover 53 is fastened in the adjacent cylinder pit in the same way as the end 53b of the adjacent pressure cover which engages in the cylinder pit 15b. This end 53b is clamped between the right wall of the cylinder pit 15b in FIG. 10 and a clamping piece 59 which is acted upon by a rotatable cam 60. This cam 60 is provided with a worm wheel so that it can be tensioned with the help of a worm 60a. The screw 60a can be rotated with a suitable key in order to tighten or loosen the clamping piece 59.

The filler 54 rests with a flat side surface on the cylinder pit wall on the left according to FIG. 10 and with its flat bottom surface rests on the bottom of the cylinder pit 15b. Its surface is curved and extends the cylindrical surface of the cylinder sector 15˝a. The upper right edge according to FIG. 10 is rounded, so that the pressure cover 53 can be stretched over this edge. The filler 54 is secured by a plurality of fastening screws 55, 56, 57 different orientations held firm and immovable. The fastening screws 55, 56, 57, which are oriented vertically, obliquely and almost parallel to the bottom of the cylinder pit 15b in the example according to FIG. 10, ensure that the filler 54 does not change its position in spite of the large pressure occurring during pressure.

In the example under consideration, the printing cylinder 15 is equipped with the filler 54 for the largest printing format, which extends up to the radius F1, that is to say that the effective circumferential length of the cylinder pit 15b is the smallest. In the case of smaller print formats, a filler piece correspondingly shorter in the circumferential direction is used. In the smallest print format indicated by the radius F2, a correspondingly narrow filler is used, and the print cover 53 then runs less inclined at its area engaging in the relatively long cylinder pit 15b, as shown in broken lines in FIG. 10. So in order to change the effective circumferential length of a cylinder pit, the actual fastening of the two ends of the pressure cover by means of the tension shaft 58 or the clamping piece 59 need not be modified; it is sufficient to dimension the cylinder sector, that is to say the support for the pressure reference, by a suitable dimension Extend or shorten the filler.

In the case of a rubber cylinder of the indirectly printing printing unit A, the procedure is such that, in order to adapt the circumferential length of the cylinder pit, the support for the rubber blanket is dimensioned accordingly, that is to say is trimmed accordingly. The greater the circumferential length of the cylinder pit, the greater the time span that is available for carrying out a pilgrim step operation.

With the combined printing machine described with the aid of the drawings, a four-color wet offset printing or, when the dampening units are out of operation and use of dry offset plates, a dry offset printing or a combination of both, as well as a four-color intaglio printing, consisting of a three-color collective printing and a single-color direct intaglio printing, can be carried out on the front of the web , and also produce a four-color offset print and a four-color intaglio print on the back of the web. The invention is not limited to the exemplary embodiment described, but instead allows for multiple variants with regard to the type, the number and the sequence of the printing units, the type of control of the draw roller units and the structure of the suction rollers. In addition to printing units, perforating units and / or cutting units can also be combined with the printing machine in the manner described above.

Claims (14)

1. Combined rotary web-fed printing machine, especially for the printing of securities, with at least two printing units (A, B) arranged in succession and with a transport device conveying the paper-web (P) through the printing units, one printing unit (A) allowing the paper web (P) to be printed with variable formats following one another, for this purpose the cylinders (2, 3) of this printing unit (A) which form the printing nip being provided with sectors separated by cylinder pits, and the transport device comprising two draw-roller units (30, 31) with associated paper-web stores (29; 32), said draw-roller units (30, 31) being installed in front of and after the printing nip and being controllable by means of individually regulated drives (30a, 31a), in order to transport the paper web running through the printing nip in the pilgrim-step mode with adjustable repeat length (RL) while the paper-web is transported uniformly in front of the paper-web store (29) positioned before the printing nip and behind the paper-web store (32) positioned after the printing nip by means of continuously driven draw-roller arrangements (27, 34), characterized in that each of the printing units (A, B) and the sections of the transport device belonging to each printing unit are designed to print the paper-web, as in the aforementioned printing unit (A), with variable formats following one another and in that the draw-roller units (30, 31; 38, 39) and their drives (30a, 31a; 38a, 39a) are at the same time devices for register correction and for printing-length correction.
2. Rotary web-fed printing machine according to Claim 1, characterized in that it has an indirectly printing printing unit (A) and at least one intaglio printing unit (B).
3. Rotary web-fed printing machine according to Claim 2, characterized in that three printing units (A, B, C) are provided, the first printing unit, as seen in the transport direction, being the indirectly printing printing unit (A) which is designed for simultaneous recto-verso printing and which has two interacting blanket cylinders (2, 3), in that the second and the third printing unit (B, C) are intaglio printing units which respectively print one side of the web and then the other with a multicolour intaglio print, the last intaglio printing unit also being equipped, on both sides of its printing nip, with paper-web stores (37', 40') and with intermittently controllable draw-roller units (38', 39'), and in that the transport device possesses a drying device (42, 43; 42', 43') respectively between the two intaglio printing units and preferably also behind the last intaglio printing unit.
4. Rotary web-fed printing machine according to Claim 2, characterized in that the first printing unit is an intaglio printing unit which is followed by the indirectly printing printing unit and a further intaglio printing unit or, conversely, by a further intaglio printing unit and the indirectly printing printing unit.
5. Rotary web-fed printing machine according to one of Claims 1 to 4, characterized in that each of the draw-roller units (30, 31; 38, 39) mentioned has only one suction roller (30b, 31b; 38b, 39b) as a draw roller, in which a constantly acting suction effect is active along that circumferential portion round which the paper web is looped, whilst the remaining circumferential portion of this suction roller undergoes no suction effect, and in that the looping extends preferably over 180°.
6. Rotary web-fed printing machine according to Claim 5, characterized in that the suction roller of the draw-roller unit consists of a fixed hollow roller core (65) and of a roller casing (61) rotatable about this and made of light material, with suction ports (62) distributed over its circumference, in that the roller core (65) is equipped on its one side with an axial connection piece (68b) for fastening to the machine stand and for connection to a vacuum source, on its other side with a bearing journal (66) and on its circumference with two radial partition walls (69) arranged at a specific angular distance from one another and enclosing a suction chamber (72) between them, in that the circumferential wall of the roller core (65) within the suction chamber has passage orifices (70), and in that the roller casing (61) is mounted rotatably by means of bearings (71, 71') at one end of the bearing journal (66) and at the other end on the connection piece (68b), the gaps between the inner circumference of the roller casing (61) and the radially outer ends of the partition walls (69) being at least approximately airtight.
7. Rotary web-fed printing machine according to Claim 6, characterized in that fastened to the two ends of the roller core (65) are annular walls (67, 68) which close off the suction chamber (72) mentioned at the two axial ends, in that the gaps between the inner circumference of the roller casing (61) and the outer circumference of the annular walls are at least approximately airtight, the annular wall (68) located on the same side as the connection piece preferably being in one piece with the connection piece (68b), on which a flanged part (63) fastened to said roller casing (61) is mounted rotatably by means of one of said bearings ( 71'), and in that the end of roller casing (61) facing away from the connection piece (68b) tapers conically to form a connecting flange (61b), which is intended for fastening to the rotor shaft of the drive motor, and is mounted on the said bearing journal (66) by means of the other of said bearings (71).
8. Rotary web-fed printing machine according to Claim 6 or 7, characterized in that sealing material (73), especially in the form of self-adhesive brushes, is arranged in said gaps, or in that the said gaps are so small that, without sealing material, they generate an air resistance sufficient for maintaining the desired vacuum in the suction chamber (72).
9. Rotary web-fed printing machine according to one of Claims 6 to 8, characterized in that the roller casing (61) consists of carbon fibres impregnated with plastic.
10. Rotary web-fed printing machine according to one of Claims 6 to 9, characterized in that adjacent suction ports (62) in the roller casing (61) are respectively arranged offset angularly in such a way that they extend along helical portions arranged in a zigzag-shaped manner.
11. Rotary web-fed printing machine according to one of Claims 1 to 10, characterized in that it has an intaglio printing unit (B, C), and in that, when there is a change of the length of the printing format, the circumferential length of the cylinder pits (15b, 15b') of the impression cylinder can be varied by means of exchangeable filler pieces of differing length (54), on which the end region of a printing covering (53) is supported.
12. Rotary web-fed printing machine according to one of Claims 1 to 11, characterized in that it has an indirectly printing printing unit (A) with two blanket cylinders (2, 3) forming the printing nip, and in that, when there is a change of the length of the printing format, on at least one of these blanket cylinders the circumferential length of the cylinder pits (2b, 3b) can be varied by an appropriate adaptation of the blanket backings.
13. Rotary web-fed printing machine according to one of Claims 1 to 12, characterized in that the regulating and control system for the two draw-roller units of a printing unit has a pilgrim-step generator (PS) receiving signals relating to the desired repeat length (RL), a first comparator (V1) designed to compare the position (x) of a register mark read off on the paper web (P) with the angular position (φ) of the printing-unit cylinders and to determine a deviation (Δx) from the ideal position of the register mark, a second comparator (V2) designed to compare the read-off printing length (DLi) of the print generated in the printing unit with the angular position (ψ) of the printing-unit cylinders and to determine a possible deviation (ΔDL) from the desired printing length, and a controller (R), preferably in the form of a process computer, which is connected to the pilgrim-step generator (PS) and the two comparators (V1, V2), receives signals relating to the angular position (φ) of the printing-unit cylinders and the angular position (αi, βi) of the draw-roller units (30, 31) and relating to the desired printing length (DL) and is designed to transmit control quantities to two power output stages (LSTG) for controlling the two drives of the draw-roller units (30, 31).
14. Rotary web-fed printing machine according to Claim 13, characterized in that an overriding process computer (PR) is provided for the machine as a whole and coordinates and optimizes the regulating and control systems of each printing unit (A, B, C).

Images