Method and system for operating a system having a collator and a printing press

Abstract

The present invention relates to a method for operating a system (2) comprising a collator (4) and a printing press (6), the collator (4) having a plurality of processing units (8) for processing one or more paper webs (18), the printing press (6) printing the paper web and outputting the same printed paper web (18) to the collator (4), the system (2) having a speed controller (34) for a plurality of follower machines to specify the speed of a lead machine such that they follow the lead machine, the printing press (6) being the lead machine and at least one of the processing units (8) of the collator (4) being a follower machine. The present invention also relates to a corresponding system (2).

Description

Technical Field

[0001] The present invention relates to a method for operating a system having a corrugator and a printing press, and to a corresponding system.

[0002] A corrugator is used to manufacture cardboard. Several paper webs are unwound from their respective unwind units and connected to each other to form a cardboard web. For this purpose, one of the paper webs is corrugated, for example, by a corrugator roller and then adhered to two non-cardboard webs. Multilayer cardboard webs having two or more cardboard paper webs are also possible. The completed cardboard web is then optionally finished using a cardboard machine, i.e., cut into individual pieces.

[0003] Furthermore, in order to manufacture a correspondingly printed cardboard web, it is possible to pre-print one of the paper webs using a printing press. The paper web is first printed and then fed to the corrugator for further processing. In principle, it is possible to wind up the first printed paper web into a roll, supply it to the unwind unit of the corrugator, unwind the roll therefrom and process it again. However, it is desirable that the printed paper web be transferred directly to the corrugator. However, the cooperation between the printing press and the corrugator is often problematic, especially with regard to the speed and web tension of the printed paper web.

[0004] In view of this background, an object of the present invention is to improve the joining operation between the corrugator and the printing press. For this purpose, an improved method for operating a system having a corrugator and a printing press should be specified. Furthermore, a corresponding system will be provided.

[0005] According to the present invention, this object is achieved by a method having the features of claim 1 and by a system having the features of claim 13. Advantageous embodiments, further developments, and variants are the subject matter of the dependent claims. The explanations regarding the method also apply to the system and vice versa. When the steps of the method are specified below, advantageous embodiments of the system result from the fact that the system is designed to carry out one or more of these steps. For this purpose, the system particularly has a correspondingly designed control unit.

[0006] This method is used to operate a system having a collator and a printing press. The collator has a plurality of processing units for processing one or more paper webs. Suitable processing units are, for example, an unwinder for unwinding a paper web, in particular a splicer for providing a continuous paper web in combination with the unwinder, a collator roller for producing a corrugated paper web, an adhesive unit for applying an adhesive to a paper web for the purpose of joining it to another paper web, a preheater for preheating the paper web, a single facer for joining a corrugated paper web to a non-corrugated web to form a single-sided corrugated web, a double facer for joining a single-sided corrugated web to a non-corrugated web to form a corrugated web, etc. Depending on the design of the collator, the processing units mentioned may be present once, multiple times, or not at all.

[0007] The printing press prints the paper web, outputs it as a printed paper web to the collator, and further processes it into a corrugated web. The term "printed paper web" is used to simplify the description of the paper web that passes through the printing press and is printed by the printing press. Preferably, the printed paper web functions as a laminated web for the corrugated web, i.e., as its outermost layer.

[0008] Preferably, the printing machine is a digital printing machine. In the following, such a design is assumed without limiting generality. In a suitable embodiment, the printing machine has a printing cylinder and a plurality of printing bars for printing the incoming paper web. The printing cylinder is in particular part of the printing unit which is the processing unit of the printing machine. "Plurality" is generally understood to mean "one or more". The incoming paper web is provided, for example, by a combination of an unwinder and a splicer. Designs with several printing cylinders and associated printing bars through which the paper web passes continuously are also suitable. For example, first, a plurality of inks are printed using a first combination of a printing cylinder and a printing bar, for example four colors (CMYK), and then a varnish is printed using a second combination of a printing cylinder and a printing bar. The above-mentioned printing cylinder for printing ink is also called an inkjet printing cylinder, and similarly, the printing cylinder for printing varnish is also called a varnish printing cylinder. Furthermore, the printing machine advantageously has one or more coating units, for example for primer or varnish, and / or one or more dryers for drying the printed matter, for example a hot air dryer or an IR dryer.

[0009] The spatial arrangement of the printing machine relative to the collator is in principle arbitrary. What is important is that the printed paper web is fed directly into the collator, i.e. it is not rewound in the collator after being wound up first. In this case, without loss of generality, an arrangement is assumed in which the printing machine is arranged parallel to the collator and then the printed paper web is introduced into the collator via a plurality of, for example two, rotating bars. However, in principle, an in-line arrangement is also suitable. Preferably, the printed paper web is fed into the collator via a combination of an unwinder and a splicer, so that the printing machine can optionally be disconnected from the collator, switched off, and then another paper web can be fed via the unwinder.

[0010] The system has a speed controller that specifies the speed of a lead machine for a plurality of follower machines so that they follow the lead machine. The speed is particularly a conveyance speed or a web speed, and then is the speed of each paper web in the system, particularly the entire printed paper web and corrugated web. The speed controller then specifies the overall speed of the lead machine as the target speed for the follower machines and controls these follower machines accordingly.

[0011] In this case, the printing press is the lead machine and at least one of the processing units of the corrugator is a follower machine. Preferably, with respect to at least speed control, all processing units of the corrugator are each follower machines so that the corrugator completely follows the printing press. This has the advantage that the printing press can be defined as the stationary point of the system and thus can be operated at a constant speed. This means that the printing press achieves significantly improved printing results, particularly compared to the opposite case where the printing press as a follower machine follows the corrugator as the lead machine. Such a design with the printing press as the follower machine is possible in itself, does not require further modification of the corrugator, and can be operated as normal, having the advantage that the combination with the corrugator is particularly simple. The printing press only needs to simply replace one of the unwinders of the corrugator for supplying the paper web. For example, a given corrugator already has a speed controller where the double facer sets the target speed, which is also adopted by other processing units and then any additional printing presses. However, in this case, the so-called natural solution is intentionally abandoned. This can improve the printing results. Further, when using the printing press as the lead machine, the tension control or dancer for adjusting the speed of the printing press to the corrugator can be omitted, simplifying the configuration of the system in this regard.

[0012] As already shown, the printing press preferably operates at a constant speed and then advantageously forms a rest point for the entire system. In an embodiment suitable for this purpose, a printing press for printing a paper web has a printing cylinder, in particular an inkjet printing cylinder already described, which is controlled by a speed controller to a constant speed (=predetermined speed), especially during web conveyance, which is the first operating mode. This ensures that the paper web flows as smoothly as possible during printing. The speed controller then comprises, so to speak, two control parts. So to speak, in the first control part, the speed of the printing press is controlled to a constant value, and in the second control part, the collator is then controlled to the speed of the printing press.

[0013] Preferably, the speed controller provides a virtual guide axis that the printing press, in particular the described printing cylinder, follows. The virtual guide axis is not an actual axis of the printing press but is provided purely electronically by the control unit of the system and parameterized accordingly. The use of the virtual guide axis has the advantage over an actual guide axis (e.g., an encoder) that the virtual guide axis generates sensor signals for control that are particularly smooth, i.e., not only low-noise but noise-free. In this context, an "actual guide axis" is understood to particularly mean that the system follows the measured speed (sensor signal). However, in this case, the details of the virtual guide axis are of secondary importance, and what is important is that it is used at all. Preferably, the control unit that provides the virtual guide axis is part of the printing press and is thus also called printer control. The virtual guide axis is then passed from the printer control via a suitable signal path to the control unit of the collator (also known as WPA control) in order to control the speed of the individual processing units accordingly. However, it is also possible in principle to distribute the control unit and the control tasks to the printing press and the collator, or separately. Therefore, without limiting its generality, only the "control unit of the system" is referred to here.

[0014] However, the virtual guide axis is not completely independent in that the speed at which the printing cylinder is controlled (i.e., the target speed) is appropriately pre-determined by the coiler automatically as part of the settings for executing a particular order, or manually by the machine operator. For example, when an order is changed and it is necessary to change the speed of the coiler when the corresponding speed is input or set, the speed of the virtual guide axis is changed, and as a result, the coiler also operates at the changed speed accordingly. In this way, the control structure and operating concept in which the coiler is changed according to the order are advantageously maintained.

[0015] The printing cylinder of a printing press, particularly an inkjet printing cylinder, preferably follows the virtual guide axis without process control and is thus excluded from web transport control, i.e., the control of the web tension of the paper web. However, such web transport control is, for convenience, part of the coiler, i.e., in one or more of the processing units of the coiler, the web tensions of various paper webs are controlled by the web transport control. The web tensions are preferably controlled separately in each processing unit. It is preferred that at least the printing cylinder be excluded from this web transport control, but other parts of the printing press, other than the printing cylinder (but away from the printing cylinder) and between the printing press and the coiler, are optionally connected to the web transport control to control the web tension within the printing press. Thus, the web tension is controlled in different parts of the system, but in particular, excluding the printing cylinder, the web transport control concept is implemented throughout the system. This is because the coiler is only controlled by the speed controller that the coiler then follows such that the web transport control also depends on the speed controller. The printing cylinder follows the virtual guide axis like all other drive parts within the system. In contrast to the printing cylinder, these other drive parts still adjust their speed through the web transport control, i.e., through control values for process control for, e.g., web tension or dancer.

[0016] Preferably, the drive unit follows the virtual guide axis at a synchronized angle. This means, in particular, that in addition to the speed controller, the position controller is also active. If the actual speed deviates from the target speed, this causes a position error, which is then corrected by position control.

[0017] Thus, to summarize, it is advantageous to use the speed specification of the collator as the speed of the printing press, with the collator then following that speed and simultaneously controlling the web tension, provided that the printing cylinders are excluded therefrom. This design is particularly suitable for web conveyance, i.e., conveying the paper web through the system during the production of the corrugated web. Thus, during web conveyance, the paper web is conveyed. Web conveyance is the first operating mode of the system (as already described above) and is useful for the actual production of the corrugated web.

[0018] In the case of some printing cylinders, not necessarily all printing cylinders are excluded from web conveyance control during web conveyance. In a preferred embodiment, only the inkjet printing cylinder is excluded from web conveyance control and the varnish printing cylinder is connected thereto.

[0019] In principle, the system preferably has one or more roller pairs as part of the web tension control concept, in which the printed paper web is successively conveyed and the web tension of the printed paper web is controlled before entering the collator downstream of the printing press. Each roller pair has a measuring roller (non-driven) for measuring the web tension (actual value) and a control roller (driven) for adjusting the web tension to a target value. The control rollers used include, for example, cooling rollers, heating rollers, temperature control rollers, press rollers, positioning rollers, or the aforementioned printing cylinders. A wide variety of designs are suitable for arranging the roller pairs along the paper web. The measuring roller of the roller pair can be arranged either upstream or downstream of the control roller of the roller pair. However, preferably, there is no measuring roller or control roller of a second roller pair between the non-driven measuring roller and the driven control roller of the first roller pair.

[0020] In contrast to web conveyance, for the simple application of tension to a paper web, embodiments are advantageous in which the control of the web tension is changed by deviating from what has been described so far and, in particular, by using one or more printing cylinders of a printing press to control the web tension of the printing press. However, the paper web is only under tension and not conveyed. Tension application is the second operating mode of the system. In principle, the same control as for web conveyance, and thus the same control direction, can be used for tension application. However, a change in control, especially such that the printing cylinders of the printing unit are currently used, is particularly advantageous when the printed paper web is prepared for splicing via a splicer (in particular, a laminated web splicer). During web conveyance, the printing press (more precisely, the printing unit, and even more precisely, its printing cylinders) forms a stationary point. Then, the control is changed by, so to speak, reversing the control direction such that the printing press is no longer the stationary point of the system but instead the splicer. In this way, tension application is performed in preparation for splicing. This makes it possible to apply tension upstream via the printing press to the paper web clamped by the splicer for splicing. The splicer forms a first clamping point, and the second clamping point is arranged upstream along the paper web and is formed, for example, by another splicer at the inlet of the printing press. In contrast to web conveyance, during the tension application of the printing cylinders, in particular inkjet printing cylinders, there are control rollers that, together with a measuring roller, form a pair of rollers for controlling the web tension. The measuring roller is also, in particular, part of the printing press.

[0021] In a suitable embodiment, the system has several measuring rollers and control rollers, which are arranged alternately along the printed paper web, with the result that there is a control roller between two measuring rollers and vice versa, i.e., there is a measuring roller between two control rollers. By changing the assignment of the measuring rollers and control rollers in a roller pair, the control direction of each roller pair for web tension control can be changed. Preferably, all the roller pairs in front of the printing cylinder (especially the inkjet printing cylinder) are the same during web conveyance and tension application, i.e., upstream of the printing cylinder, and the control direction remains unchanged. However, advantageously, from the printing cylinder and downstream thereof for tension application (especially for the preparation of splicing of the printed paper web as described above), the control direction is reversed compared to web conveyance. For this purpose, different measuring rollers are assigned to each control roller (or vice versa). For example, starting from the printing cylinder, the roller pairs downstream of the printing cylinder during web conveyance are formed such that the control roller of each roller pair is arranged downstream of the associated measuring roller. For tension application, then the measuring roller is assigned to each control roller upstream of this control roller. This measuring roller may be the measuring roller of another roller pair during web conveyance. Preferably, for the purpose of tension application, all the roller pairs are formed such that in each roller pair, the control roller is arranged downstream of the associated measuring roller, with the result that the control is carried out overall only in one direction towards the inlet of the printing press. Based on this, during web conveyance, the printing cylinder (inkjet printing cylinder) and the roller pairs downstream thereof are preferably formed such that the control roller is arranged upstream of the associated measuring roller. As a result, the control is carried out overall in the opposite direction from the printing cylinder, away from the printing cylinder (i.e., upstream of it in the upstream direction and downstream of it in the downstream direction).

[0022] As already described above, the corrugator is conveniently controlled starting from its double facer (also called the tensioning and heating section). Therefore, it is preferable for all other processing units of the corrugator to follow the double facer with respect to the speed controller. In other words, the speed of the other processing units is controlled according to the speed of the double facer. This basic concept is preferably maintained here, where the double facer does not independently specify the speed, but rather follows the printing press as described above, particularly with different speeds specified by the virtual guide axis. Since the other processing units currently continue to follow the double facer here, the corrugator is a follower machine of the printing press as a whole. In other words, the double facer, which was previously used as a master, follows the printing press and thus is only a master of the corrugator and not the master of the entire system. The printing cylinder of the printing press is currently the master of the entire system.

[0023] Since the double facer is designed to follow the printing press, the speed of the double facer, which was previously not controlled, is controlled to match the speed specified by the printing press. Therefore, additional adjustment of the web tension between the printing press and the corrugator is particularly useful. This is extremely generally applicable even when the processing units other than the double facer were previously masters.

[0024] In a suitable embodiment having a double facer, in order to adjust the web tension between the printing press and the collator, the web tension of the printed paper web is controlled at the last part before the double facer. In this way, it is also advantageous to adjust the speed at the double facer, especially when entering the collator where it was not previously controlled. To control the web tension at the last part, the system has a pair of rollers, a control roller for adjusting the web tension at the last part and a measuring roller for measuring the web tension at the last part. The control roller is part of the double facer and the measuring roller is arranged either outside and upstream of it or vice versa. The term "last part" refers to the part between the measuring roller and the control roller. As an alternative to the above solution having a pair of rollers, a dancer between the double facer and the printing press is also suitable for adjusting the web tension.

[0025] In a suitable design, the feedback of the control loop is realized at the dancer position or alternatively by web tension measurement. Depending on the selected design, the measuring rollers used are arranged at different positions. In a suitable embodiment, since there is a splicer between the printing press and the collator (more precisely, its double facer), the dancer position is preferably used to adjust the speed of the collator or the double facer. However, if such a splicer is not available at the specified position, it is convenient to use a web tension measuring roller to adjust the specified speed.

[0026] It is particularly advantageous to adjust the speed when entering the double facer using a splicer. In a suitable embodiment, the collator has a corresponding splicer arranged along the printed paper web between the printing press and the double facer, i.e., downstream of the printing press and upstream of the double facer. The splicer then has a measuring roller by which the web tension is measured, which is controlled by the double facer, in particular by the control roller described above. The splicer is particularly combined with an unwinder through which the printed paper web is fed into the collator and then, if necessary, another paper web can be fed by the unwinder and the splicer.

[0027] The system according to the invention has a control unit (in particular, as already described above) designed to carry out the method described above.

Brief Description of the Drawings

[0028] Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the drawings. The drawings are shown schematically.

Figure 1

Figure 2

Figure 3

[0029] FIG. 1 shows a very simplified system 2 having a collator 4 and a printing press 6. The collator 4 has a plurality of processing units 8 for processing one or more paper webs. Suitable processing units 8 are, for example, an unwinder 10 for unwinding the paper web, a splicer 12 for providing a continuous paper web, a collator roller, an adhesive unit, a preheater, a single facer, a double facer 14 for joining a single-sided corrugated web to a non-corrugated web to form a corrugated web 16, etc.

[0030] The printing press 6 prints a paper web and outputs it as a printed paper web 18 to the corrugator 4 for further processing into a corrugated web 16. The term "printed paper web" is used to simplify the description of the paper web that passes through the printing press 6 and is printed by the printing press.

[0031] In the illustrated exemplary embodiment, the printing press 6 is a digital printing press. Exemplary embodiments of the printing press 6 can be seen in FIGS. 2 and 3, which each show a part of the system 2 in different operating modes. Only the unwind 10, splicer 12, and double facer 14 of the corrugator 4 are shown in FIGS. 2 and 3, through which the printed paper web 18 is supplied to the corrugator 4. Here, the printing press 6 has, for example, two printing cylinders 20 and a plurality of printing bars 22 for printing the incoming paper web 18. The incoming paper web 18 is here provided by a combination of the unwind 10 and the splicer 12, which combination is also called the unwind and splicing unit E1 and forms the inlet of the printing press 6. Downstream of this is an optional inlet tension group E2, downstream of which is an optional corona pretreatment E3, downstream of which is an optional precoating E4, and downstream of which is then a printing unit E5 having a first printing cylinder 20 (inkjet printing cylinder) and a plurality of printing bars 22 for printing ink. Downstream of this, an optional varnish treatment E6 is first carried out, and downstream of this, an optional digital printing varnish E7 having an unstated second printing cylinder 20 (varnish printing cylinder) and printing bars 22 is carried out.

[0032] The spatial arrangement of the printing press 6 relative to the collator 4 is basically arbitrary. In FIG. 1, for example, the printing press 6 is arranged parallel to the collator 4, and the printed paper web 18 is then introduced into the collator 4 via a plurality of rotating bars 30. In FIGS. 2 and 3, only two rotating bars 30 are shown as an example, but the number can vary, and a design without rotating bars 30 is also possible. In this case, the printed paper web 18 is then supplied to the collator 4 via a combination of the unwind 10 and the splicer 12, so that the printing press 6 can be optionally disconnected from the collator 4, the switch can be turned off, and then another paper web is supplied to the collator 4 by the unwind 10.

[0033] The system 2 has a speed controller 34 for a plurality of follower machines to specify the speed of the lead machine so that they follow the lead machine. The speed is the conveyance speed or the web speed, and then the speed of each paper web in the system 2, particularly the entire printed paper web 18 and the cardboard web 16. The speed controller 34 specifies the speed of the entire lead machine as the target speed of the follower machines and controls these follower machines accordingly. In this case, the printing press 6 is the lead machine, and at least one of the processing units 8 of the collator 4 is a follower machine. In this case, the collator 4 can even completely follow the printing press 6, at least with respect to speed control.

[0034] Therefore, the printing press 6 operates at a constant speed and then forms the stationary point of the entire system 2. For this purpose, one of the printing cylinders 20 (in this case, the first printing cylinder 20 of the printing unit E5) is controlled to a constant speed using the speed controller 34. In the illustrated exemplary embodiment, the speed controller 34 also provides a virtual guide axis 36 that the printing press 6, particularly its printing cylinder 20, follows. FIG. 1 shows the control unit 38 of the system 2 including the speed controller 34 having the virtual guide axis 36. In principle, it is possible to integrate the control unit 38 into the printing press 6 or the collator 4, or divide it between them.

[0035] However, the virtual guide axis 36 is not completely independent in that the speed at which the printing cylinder 20 is controlled is, for example, predetermined by the collator 4. For example, when it is necessary to change the speed of the collator 4 when the order is changed and the corresponding speed is input or set, the speed of the virtual guide axis 36 is changed, and as a result, the collator 4 operates at the correspondingly changed speed.

[0036] The first printing cylinder 20 of the printing press 6 follows the virtual guide axis 36 without a process controller and is thus excluded from web transport control, i.e., control of the web tension of the paper web 18. However, such web transport control is, in this case, part of the collator 4, i.e., the web tensions of the various paper webs are controlled by web transport control in the processing unit 8 of the collator 4. At least the first printing cylinder 20 (inkjet printing cylinder) is excluded from this web transport control, but other parts of the printing press 6 remote from the printing cylinder 20 are optionally connected to the web transport control and, in this case, also to the second printing cylinder 20 (varnish printing cylinder). Thus, a web transport control concept in which the web tension is controlled in different parts of the system 2, except in particular for the printing cylinder 20, is implemented throughout the system. This is then controlled only by the speed controller 34 that the collator 4 follows, such that the web transport control also depends on the speed controller 34. This design is suitable for transporting the paper web 18 through the system 2 during web transport, i.e., during the production of the cardboard web 16. This web transport is the first operating mode of the system 2 and is shown in FIG. 2.

[0037] As a rule, system 2 advantageously has one or more pairs of rollers as part of a web tension control concept, through which the printed paper web 18 is successively conveyed and the web tension of the printed paper web 18 is controlled before entering the folder 4 downstream of the printing press 6. The pairs of rollers are indicated by arrows 44 in FIGS. 2 and 3, each arrow 44 starting at the measuring roller 42 of the pair of rollers and ending at the control roller 40 of the pair of rollers. For clarity, not all control rollers 40 and measuring rollers 42 are explicitly provided with reference numerals, but their positions and functions can be clearly seen from the arrows 44 and their paths. The path of arrow 44, i.e., either in the upstream or downstream direction, indicates the respective set control direction of the pair of rollers. As can be seen from a comparison of FIGS. 2 and 3, the control direction can be changed by changing the assignment of the measuring roller 42 and the control roller 40 to the pair of rollers. Each control roller 40 is a drive roller and each measuring roller 42 is a non-drive roller. The control rollers 40 used include, for example, the cooling roller 46, a heating roller, a temperature control roller, a pressing roller, a positioning roller, or the aforementioned printing cylinder 20. A wide variety of designs are suitable for the arrangement of the pairs of rollers along the paper web 18, and possible exemplary embodiments are shown in FIGS. 2 and 3.

[0038] In contrast to web conveyance, the printing cylinder 20 is used simply to apply tension to the paper web 18, particularly the printing cylinder 20 of the printing unit E5 explicitly shown here, in order to control the web tension in the printing press 6. In this case, the paper web 18 is only tensioned and not conveyed. Tension application is the second operating mode of the system 2, and an exemplary embodiment thereof is shown in FIG. 3. The measuring rollers 42 and the control rollers 40 are basically arranged alternately along the printed paper web 18, with the control roller 40 arranged between two measuring rollers 42 and vice versa, i.e., the measuring roller 42 is arranged between two control rollers 40. By mutually changing the assignment of the measuring rollers 42 and the control rollers 40 in the roller pairs, the control direction of the web tension control can be changed. In FIGS. 2 and 3, all the roller pairs upstream of the shown printing cylinder 20 have the same control direction during web conveyance and tension application, i.e., upstream of the printing cylinder 20, the control direction remains unchanged. However, as can be seen in FIG. 3, from the printing cylinder 20 and downstream thereof, for tension application, the control direction is reversed compared to the web conveyance in FIG. 2. For this purpose, different measuring rollers 42 are assigned to their respective control rollers 40 (or vice versa) such that the explicitly shown printing cylinder 20 is also used as the control roller 40. According to FIG. 2, starting from the printing cylinder 20, the roller pairs downstream thereof during web conveyance are formed such that the control roller 40 of each roller pair is arranged downstream of the associated measuring roller 42. For tension application, as shown in FIG. 3, the measuring rollers 42 are then assigned to their respective control rollers 40 upstream of the control rollers 40. This measuring roller 42 may have been the measuring roller 42 of another roller pair during web conveyance. In this case, for the purpose of tension application, all the roller pairs are formed such that in each roller pair, the control roller 40 is arranged downstream of the associated measuring roller 42, and as a result, the control is carried out overall only in one direction towards the inlet of the printing press 6. Based on this, during web conveyance, the printing cylinder 20 and the roller pairs downstream thereof are formed such that in this case, the control roller 40 is arranged upstream of the associated measuring roller 42.As a result, the control is performed as a whole in the opposite direction from the printing cylinder 20, away from the printing cylinder 20 (i.e., its upstream in the upstream direction and its downstream in the downstream direction).

[0039] In this case, the folder 4 is controlled starting from the double facer 14. Therefore, all other processing units 8 of the folder 4 follow the double facer 14 with respect to the speed controller 34. Since the double facer 14 follows the printing press 6 here, the speed of the double facer 14, which was not previously controlled, is controlled here to conform to the speed specified by the printing press 6. Thus, an additional adjustment of the web tension between the printing press 6 and the folder 4 is necessary. This is very generally applicable even when the processing unit 8 other than the double facer 14 was previously the master of the folder 4.

[0040] In the illustrated exemplary embodiment having the double facer 14, in order to adjust the web tension between the printing press 6 and the folder 4, the web tension of the printed paper web 18 is controlled at the last portion 50 before the double facer 14. Thereby, adjustment of the speed when entering the folder 4 is realized. To control the web tension of the last portion 50, the system 2 has a pair of rollers, a control roller 40 for adjusting the web tension of the last portion 50 and a measuring roller 42 for measuring the web tension of the last portion 42. In FIG. 2, the control roller 40 is part of the double facer 14.

[0041] As can be seen in FIG. 2, there are two suitable positions for the associated measuring roller 42 of the roller pair: The first possible measuring roller 42 is arranged between the folder 4 and the rotary bar 30 upstream of the splicer 12, and the second possible measuring roller 42 is arranged downstream of the splicer 12 or is part thereof. The term "last portion" 50 refers to the portion between each measuring roller 42 and the control roller 40. Although both of the described measuring rollers 42 are shown in FIG. 2, typically only one is used depending on the presence or absence of the splicer 12.

Description of Reference Numerals

[0042] 2 System 4 Collator 6 Printing Machine 8 Processing Unit 10 Unwinder 12 Splicer 14 Double Facer 16 Corrugated Web 18 Printed Paper Web 20 Printing Cylinder 22 Printing Bar 30 Rotating Bar 34 Speed Controller 36 Virtual Guide Axis 38 Control Unit 40 Control Roller 42 Measuring Roller 44 Arrow (indicating roller pair) 50 Last Part E1 Unwinding and Splicing Unit E2 Inlet Tension Group E3 Corona Pretreatment E4 Precoating E5 Printing Unit E6 Varnish Treatment E7 Digital Printing Varnish

Claims

1. A method of operating a system (2) having a collator (4) and a printing press (6), comprising: - the collator (4) having a plurality of processing units (8) for processing one or more paper webs (18); - the printing press (6) printing a paper web and outputting the same printed paper web (18) to the collator (4); - the system (2) having a speed controller (34) for specifying the speed of the lead machine for a plurality of follower machines such that the plurality of follower machines follow the lead machine; - the printing press (6) being the lead machine; - at least one of the processing units (8) of the collator (4) being a follower machine.

2. The printing press (6) for printing the paper web (18) having a printing cylinder (20) controlled at a constant speed by the speed controller (34). The method according to claim 1.

3. The printing cylinder (20) is used to control the web tension in the printing press (6) to apply tension to the paper web (18), and the paper web (18) is only tensioned and not conveyed. The method according to claim 2.

4. The speed controller (34) provides a virtual guide axis (36) for the printing press (6) to follow. The method according to claims 1 to 3.

5. The system (2) has one or more roller pairs for controlling the web tension of the printed paper web (18) before the printed paper web (18) is conveyed and enters the collator (4) downstream of the printing press (6). The method according to any one of claims 1 to 4.

6. Each roller pair has a control roller (40) and a measuring roller (42). For the purpose of applying tension, all roller pairs are formed such that in each roller pair, the control roller (40) is arranged downstream of the associated measuring roller (42). Starting from this, during web conveyance, the roller pair and its downstream from the printing cylinder (20) are formed such that the control roller (40) is arranged upstream of the associated measuring roller (42). The method according to claim 5.

7. During web conveyance, the printing press (6) forms a stationary point. For preparation of splicing by the splicer (12), the control of the web tension is changed such that the printing press (6) no longer forms the stationary point of the system and forms the splicer (12). The method according to claim 5 or 6.

8. One of the processing units (8) of the collator (4) is a double facer (14) to which the printed paper web (18) is supplied. The method according to any one of claims 1 to 7.

9. All remaining processing units (8) of the collator (4) follow the double facer (14) with respect to the speed controller (34). The method according to claim 8.

10. The double facer (14) controls the web tension of the printed paper web (18) at the last previous part (50) in front of the double facer (14). The method according to claim 8 or 9.

11. The collator (4) has a splicer (12) arranged between the printing press (6) and the double facer (14). The splicer (12) has a measuring roller (42) for measuring the web tension such that it is then controlled by the double facer (14). The method according to claim 10.

12. The printing press (6) is a digital printing press. The method according to any one of claims 1 to 11.

13. A system (2) having a control unit (38) designed to execute the method according to any one of claims 1 to 12.

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