Procedure for processing a printed strip and installation for it

Abstract

The invention relates to a method for processing a web (4) printed with an image (6), wherein the web (4) is fed into a cutting / slitting unit (14) by which it is processed at various positions (16) in the longitudinal direction (L), wherein before the cutting / slitting unit (14) the web has a width (B), wherein an actual measurement (I) for the width (B) is measured, and the cutting / slitting unit (14) is adjusted based on the actual measurement (I) and a target measurement (S) for the width (B) so that the processing positions (16) are adapted to the printed image (6). The invention also relates to a corresponding installation (2) for such processing.

Description

[0001] The invention relates to a method for processing a web that is printed with a printed image, i.e., a printed web. The invention further relates to a corresponding apparatus for this purpose.

[0002] An example of a web is a corrugated board web. Such a web is composed of several layers of paper and may also be printed. The corrugated board web is produced using a corrugating machine, at the end of which it is typically cut into individual sheets, which are then further cut into individual sheets, e.g., folding boxes. For this purpose, the corrugated board web is typically cut lengthwise and crosswise, thereby dividing it into individual sheets. If necessary, the corrugated board web is also scored lengthwise and / or crosswise.

[0003] Often, the sheets need to be printed, for example with an image, a logo, a decoration, or something similar. The corresponding print image can be applied to the individual sheets either after longitudinal and transverse cutting or beforehand. In the latter case, the print image is called a "preprint." With preprinting, the dimensional accuracy of the corrugated board is problematic, because changes in the board's dimensions between printing and longitudinal and transverse cutting regularly result in the cuts produced during these processes not aligning perfectly with the print. The same problem exists with creasing.

[0004] EP 3 337 666 B1 describes a printing system in which graphics are printed onto a single substrate web for several different arrangements of corrugated cardboard boxes to be lined with the web, and machine-readable images representing corrugating machine control information for producing these different arrangements of boxes. The corrugating machine control information includes registration marks representing positional information used to dynamically adjust the position of a corrugated board and / or cutting and folding tools for each of the different arrangements.

[0005] EP 3 360 639 B1 describes a method for producing blanks from corrugated board, comprising cutting a corrugated board web with at least one non-moldable, variable cutting tool, wherein the cutting tool introduces cutting lines into the material web, creating the contour of a blank. A planning unit plans the position of the blanks in the corrugated board web, taking into account the expected shrinkage behavior of the still dimensionally unstable corrugated board web caused by the non-moldable cutting tool and allowing this to be calculated and adjusted in advance by scaling the planned blank.

[0006] Against this background, an object of the invention is to improve the processing of a printed web, in particular the cutting and / or creasing of a printed web, especially corrugated board. A suitable method and apparatus for this purpose are to be specified.

[0007] The problem is solved according to the invention by a method with the features of claim 1 and by a system with the features of claim 10. Advantageous embodiments, further developments, and variants are the subject of the dependent claims. The descriptions relating to the method also apply mutatis mutandis to the system and vice versa. Advantageous embodiments of the system result from its configuration to execute the method described below, specifically one or more of its steps. For this purpose, the system includes, in particular, a control unit that is configured accordingly.

[0008] The method according to the invention is used for processing a web printed with a printed image. The printing is carried out, in particular, using a printing press and is not itself necessarily part of the method described here. The printed image includes, in particular, everything printed on the web (e.g., images, logos, decorations, lettering, etc. for the individual sheets or sheets and / or control codes, alignment marks, etc. for the system). In a suitable embodiment, the printing is part of the method described here, but this is not mandatory. In a suitable embodiment, the printing is carried out inline with the processing. The web is, in particular, made of paper and is either single-layered or multi-layered. Preferably, the web is a corrugated board web and thus multi-layered.The processing is generally carried out by a machine, preferably a corrugated board machine, which will be assumed hereafter without limitation of generality. The processing takes place after the printing of the image; that is, in the processing described below, a preprint is involved, in particular the image is printed onto a single sheet of paper before it is bonded to further sheets of paper in the corrugated board machine to form the corrugated board web.

[0009] The web is fed to a cutting / creasing unit of the system, which processes the web longitudinally at a number of processing positions (i.e., cutting and / or creasing positions). A cutting / creasing unit is specifically understood to be a unit designed either to cut the web, to crease the web, or both. Accordingly, the cutting / creasing unit introduces one or more cuts and / or grooves into the web, specifically longitudinal cuts and / or grooves, since the processing is performed longitudinally. For the purposes of this discussion, and without loss of generality, we will assume a cutting and creasing unit that both cuts and creases the web. The longitudinal direction corresponds to the web's conveying direction through the system.The processing positions are those positions along the web where the cutting / creasing unit makes one or more cuts and / or creases. These cuts and / or creases are used, in particular, to cut the corrugated board web into individual sheets and / or to create fold, crease, or crease edges on the sheets or subsequent sheets, for example, to form them into boxes or similar items. The process of making cuts and / or creases, and thus the processing by the cutting / creasing unit, is also referred to as "cutting," and the corresponding processing positions are also referred to as "cutting."

[0010] In a suitable configuration, the cutting / creasing unit is located downstream of a so-called double-facer of the system. Within the double-facer, several intermediate products for a corrugated board web are assembled to form the actual corrugated board web. The double-facer also marks the end of a so-called "wet end" of the system (and is part of this system), which is followed by a so-called "dry end." This dry end is used to convert the corrugated board web into individual panels and then into individual sheets. The cutting / creasing unit is specifically part of the dry end of the system. Ideally, the cutting / creasing unit even cuts the web into several separate sub-webs (i.e., panels) lengthwise. The cutting / creasing unit is therefore also referred to as a longitudinal cutter. The sub-webs do not necessarily have to be identical but can also differ from one another, particularly with regard to the printed image.Downstream of the cutting / creasing unit, the system preferably includes a cross cutter, which cuts the web sections transversely (i.e., perpendicular to the longitudinal direction) and thus divides them into individual sheets. Optionally, a splitter is arranged between the cutting / creasing unit and the cross cutter. Furthermore, optionally, a short cross cutter is arranged between the double facer and the cutting / creasing unit. This short cross cutter, like the transverse cutter, cuts the web transversely, but with the aim of sorting out rejects or unused sections of the web.

[0011] Upstream of the cutting / creasing unit, the web has an actual width, often simply referred to as the width. The actual width is the web's true width and is measured in the transverse direction. In this process, an actual width measurement is taken, and the cutting / creasing unit is adjusted based on this measurement and a target width measurement so that the processing positions are adapted to the printed image. In a suitable embodiment, the actual width measurement is taken, and a scaling factor is determined from this measurement together with the target width measurement to adjust the processing positions to the width. Generally, it is advantageous to measure the width directly so that the actual width measurement is identical to the actual width. However, other measurements are equally suitable as actual width measurements, in particular the distance between two printed features of the image or, more generally, the distance between any features of the web.The distance is measured in the transverse direction and thus corresponds to a portion of the width. Crucially, as soon as the width varies, the actual dimension also varies due to the principle of measurement. Therefore, by measuring the actual dimension, a variation in the actual width can be detected.

[0012] The cutting / creasing unit is adjusted based on the actual and target dimensions so that the processing positions are adapted to the printed image. More precisely, in a suitable embodiment, the cutting / creasing unit is adjusted based on the aforementioned scaling factor so that the processing positions are adapted to the printed image. The cutting / creasing unit is therefore adjustable and is advantageously automatically adjusted based on the actual width (using the actual dimension) so that the cuts and / or creases always correspond exactly to the printed image. For this purpose, the processing positions, i.e., the layout of the cuts and / or creases, are scaled using the scaling factor. Any variation in the actual width, and thus any unwanted scaling of the printed image, is compensated for by a corresponding scaling of the cutting / creasing unit.A key concept of the invention is therefore that the processing positions of the cutting / creasing unit are adapted to the actual printed image, so that the resulting cuts and / or creases correspond more closely to the actual printed image. In other words, the cutting process is scaled and thus adapted to the actual dimensions of the printed image. Any resulting deviation of the actual dimensions of the blanks / sheets from the specified target dimensions, particularly those derived from the order data, is accepted. This contrasts with the reverse approach of adapting the printed image to fixed processing positions, i.e., positioning the cuts and / or creases exactly as specified in the order data (although such control by scaling the printed image is additionally advantageous, as described below).In this case, the target dimensions are maintained, but with the disadvantage of a less than optimally positioned print image if the web dimensions change. Specifically, cuts made according to the outer cutting dimensions will then regularly no longer match the print image. For example, the web is divided into five identical sub-webs by the cutting / creasing unit, meaning the print image has five identical images side by side in the transverse direction, which must be separated accordingly. A specific width is specified as the target dimension in the job data. On its way to the cutting / creasing unit, the web experiences an unexpected dimensional change, e.g., the web shrinks less than expected, and now has an actual width that is larger than a target width that is identical to the target dimension or results from the target dimension (and possibly an anticipated dimensional change that does not actually occur).When the paper is cut, this results in parts of the image from one section overlapping the adjacent section. For example, if you look at a single sheet that has already been formed into a folding carton, the printed image appears shifted relative to the edges and margins of the carton; that is, the image edge and the cut edge do not align. Since the paper is typically fed into the cutting and creasing unit with the center aligned, this error increases laterally outwards.

[0013] In contrast to the aforementioned EP 3 337 666 B1, the present case involves a true scaling of the machining positions and the resulting cuts and / or grooves; that is, the actual dimensions of the printed area change. In contrast, EP 3 337 666 B1 merely positions the tools relative to the printed image or corresponding marks to compensate for any deviation; however, the tool itself is not scaled. Thus, only translation (slippage) is compensated for, but no scaling (shrinkage) of the web or the printed image is performed.

[0014] In the aforementioned EP 3 360 639 B1, the web can be printed either before or after cutting. The cutting tools are then adjusted according to the expected shrinkage so that the final corrugated board sheet has the desired dimensions after all shrinkage processes are complete. The cut is thus adapted to the anticipated shrinkage. In contrast, in the present case, the cut is adjusted to the actual shrinkage in such a way that the final dimensions (target dimensions) may not be precisely maintained, but rather the cut is adjusted to the printed image so that the distance between the image edge and the cut edge is identical.

[0015] In addition to adjusting the processing positions to the printed image, it is also advantageous to consider anticipated shrinkage processes, or more generally, dimensional changes in the web. Accordingly, this method estimates (anticipates) dimensional changes in the web during processing and accounts for them by scaling, or in particular enlarging, the printed image on the printing press. This allows the adjustment of the processing positions to the printed image to compensate for variations in the estimated dimensional change. In this case, printing is a key component of the described process. The estimated dimensional change is primarily an expected change that does not necessarily occur completely as the web moves through the system. Consequently, variations from the estimated dimensional change regularly occur.The method described here thus advantageously incorporates two compensation mechanisms for any dimensional changes in the web: one for an estimated dimensional change and another for an actual dimensional change, specifically a variation (or deviation) from the estimated dimensional change. First, the printed image itself is scaled in advance depending on the anticipated dimensional change; for example, the target dimensions of the printed image are multiplied by a corresponding scaling factor. The anticipated dimensional change is based primarily on empirical values, which depend in particular on the specific job and the paper used. However, the anticipated dimensional change does not typically account for variations during operation, i.e., dynamic dimensional changes resulting, for example, from varying web speeds or from variations in drying or moistening the web.The method described here specifically addresses such dimensional changes. By measuring the actual dimension, precisely this change is detected and then dynamically compensated for, preferably in real time and automatically, by scaling the processing positions. This results in a two-stage correction process. The first stage involves a coarse, static correction by adjusting the print image to the anticipated dimensional change, particularly in advance. The second stage involves a fine, dynamic correction by adjusting the processing positions to the print image. This adjustment to the print image is achieved indirectly through the measurement of the actual dimension.In the first stage, an offset is set by scaling the printed image, around which the scaling of the cutting and creasing unit is then dynamically controlled in the second stage.

[0016] Alternatively or additionally, a further compensation mechanism is used to scale the printed image from the actual width to the target width, thus adjusting the printed image to the target dimensions (control by scaling the printed image). This control is implemented particularly before the web is fed to the cutting / creasing unit. This is especially advantageous in an inline operation where a printing press and a corrugated board machine are operated together inline. In this case, the printing press is located upstream of the corrugated board machine or integrated into the corrugated board machine upstream of the cutting / creasing unit. Here, too, printing is a key part of the process described. A disadvantage is that the printed image downstream of the printing press, until the actual width is measured, cannot be further influenced or corrected by scaling the printed image.However, further corrections can be advantageously made by adjusting the cutting / grooving unit as already described.

[0017] Dimensional changes in the web occur during operation, particularly due to one or more wetting and / or drying cycles within the system. The addition and removal of moisture causes the web to expand or contract. In the dry end, relative to the wet end, shrinkage regularly occurs, which depends primarily on the web speed and thus the time the web takes to reach the cutting / creasing unit and during which it releases moisture into the environment.

[0018] The scaling factor is calculated from the actual and target dimensions, for example, simply as the ratio of actual to target dimensions or in another suitable way. Depending on how the actual and target dimensions are defined, a conversion may be necessary beforehand. For example, if the actual dimension is the width of the entire web and the target dimension is the width of a sub-web, then the actual dimension must first be divided by the number of sub-webs, or conversely, the target dimension multiplied by the number of sub-webs. In another example, if the actual dimension is the distance between two print features, then the actual dimension is converted to the web width based on the known position of the print features (from the order data), and then the calculation is performed as in the previous example. The target dimension is taken from the order data for processing the web and is typically specified by the customer.The target dimension is a measure of what dimensions the individual sheets / panels should ultimately have, e.g., simply the sum of the widths of the individual webs if the actual dimension is simply the width of the entire web. The target dimension also specifies the processing positions, which are then scaled in the procedure described here to adapt to the actual print image.

[0019] To ensure optimal adaptation of the processing positions to the printed image, the actual dimension is measured as close as possible to the cutting / creasing unit. In a suitable embodiment, the actual dimension is measured at most 50 m, at most 40 m, at most 30 m, at most 20 m, or at most 10 m, preferably at most 1 m, upstream of the cutting / creasing unit. This way, any dimensional changes are captured as fully as possible, resulting in a particularly accurate adaptation to the actual printed image.

[0020] As already indicated, various designs for the actual dimension are possible and suitable; the essential point is that this allows conclusions to be drawn about the actual width and thus about the dimensions of the actual printed image.

[0021] In In a first suitable embodiment, the actual dimension is simply the actual width, as described above. The actual dimension is measured, for example, using web width or web edge detection; the system includes a corresponding sensor unit for this purpose. A particularly advantageous embodiment is one in which the web has at least two layers of different widths, so that by measuring the respective widths of the two layers and comparing them, the actual width of the web, and thus the dimensional change, is determined.

[0022] In a second suitable embodiment, the actual dimension is the distance between two printed features of the print image. In this embodiment, the printed image is directly analyzed to detect any dimensional changes in the web and the printed image. Which specific printed features are used is initially irrelevant. However, it is advantageous if these are as far apart as possible along the width of the web, i.e., if there is the largest possible distance between the two printed features in the transverse direction. This ensures that the measurement of the actual dimension has sufficient resolution to detect the typically small dimensional changes. The anticipated dimensional change is regularly about 0.7%, the variation of which in operation is then smaller and regularly amounts to a maximum of 0.3% (in both directions, i.e., + / -0.3%), and in particular about 0.2%. With a web width of, for example, 2800 mm, this is only about 5 to 6 mm.Starting from the center of the web, the distance to either side is a maximum of 3 mm. Accordingly, a distance of at least 50% of the web width is advantageously formed between the two printing features. This ensures that the two printing features are typically located on different web sections, preferably on the two outermost sections – one on the operator side of the system and one on the drive side. Excessively small distances are unsuitable depending on the measurement resolution.

[0023] In principle, all features present in the printed image are suitable as printing features. Suitable printing features include longitudinal lines (e.g., for web edge measurement), logos, images or image elements (e.g., edges, borders), and codes (e.g., QR or bar codes), either as part of the printing on the sheets and / or for controlling the machine (so-called control codes). The use of printing features that are already present and do not need to be printed separately is particularly advantageous. For example, control codes for the subsequent cross cutter are especially suitable. These control codes serve primarily to activate the cross cutter and thereby create a cross-section at a specific position relative to the control code.

[0024] In an advantageous embodiment, the actual dimension is determined by means of two sensors, which simultaneously adjust the entire cutting / creasing unit relative to the web path into the cutting / creasing unit. The web path refers specifically to the position of the web relative to the transverse direction. The two sensors are part of a sensor unit, which in turn is part of the system. The web does not necessarily enter the cutting / creasing unit at a specific point, but can be shifted in the transverse direction, depending on how the web is fed into the system. Particularly when the system processes a web whose width is less than the maximum width the system can handle, the web path can be centered, closer to the operator side, or closer to the drive side of the system.Accordingly, tracking of the cutting / creasing unit is required to adjust the processing positions to the overall web path, initially independent of any dimensional changes. For this purpose, the system is equipped with the aforementioned two sensors, which measure the web path and then, based on this measurement, correctly position the cutting / creasing unit in the transverse direction. These two sensors also measure the actual dimensions. The sensors are designed accordingly, for example, to detect the aforementioned printing characteristics.

[0025] The precise design of the sensor unit and its sensors, and how the print characteristics (or web width) are detected, is of secondary importance for the method described here. What is important is that the actual dimension is measurable, however it is defined. As an alternative to the web path sensors described, a sensor unit that is also fundamentally suitable is regularly used directly after a printing unit that prints the image onto the web, in order to verify that image. Such a sensor unit is also suitable for detecting the print characteristics, but for this purpose, it is positioned as close as possible to the cutting / creasing unit.

[0026] To create cuts and / or grooves at the processing positions, the cutting / creasing unit has several processing elements. These processing elements are arranged along the transverse direction. The processing elements are designed for the mechanical processing of the web, creating cuts and / or grooves through mechanical action. Each processing element, for example, has a pair of rollers with two rollers, each with a cutting blade or a creasing contour. In this case, the processing elements are adjustable relative to each other, and the cutting / creasing unit is adjusted by moving the processing elements relative to each other. In other words, the processing positions are scaled and adapted to the printed image by adjusting the processing elements relative to each other, for example, by appropriately increasing or decreasing their distance in the transverse direction.

[0027] In a preferred embodiment, the machining elements are designed for parallel positioning and are adjustable separately from one another for this purpose. In particular, the cutting / grooving unit has a separate adjustment mechanism (e.g., with a spindle) for each of the machining elements, and the adjustment mechanisms can be controlled independently of one another. This contrasts with serial positioning, which is typically unsuitable for the method described here, since only a single adjustment mechanism is used for several machining elements.

[0028] The system according to the invention is used for processing a web printed with an image. The system includes a cutting / creasing unit to which the web is fed in order to process it at a number of processing positions in the longitudinal direction. Upstream of the cutting / creasing unit, the web has an actual width. The system also includes a sensor unit configured to measure the actual width and a control unit configured to determine a scaling factor from the actual width together with a target width in order to adapt the processing positions to the actual width. The control unit is then further configured to adjust the cutting / creasing unit, depending on the scaling factor, such that the processing positions are adapted to the printed image. The above descriptions apply analogously to the system.

[0029] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Each drawing schematically shows: Fig. 1 a system, Fig. 2 a flowchart for a process, Fig. 3 a web with printed image, Fig. 4 the web made of Fig. 3 after a change in dimensions, Fig. 5 the path made of Fig. 4 , after an adjustment of processing positions to the printed image, Fig. 6 a distance between two printed features as an actual dimension, Fig. 7 a cutting / creasing unit of the system made of Fig. 1 .

[0030] In Fig. 1 Figure 2 shows an embodiment of a system 2 for processing a web 4. The web 4 is printed with a print image 6, which includes everything printed on the web 4 (e.g., images, logos 8, decorations 10, lettering, control codes 12, adjustment marks, etc.). Printing is not necessarily part of the process described here for processing the web 4. In the embodiment shown, the web 4 is made of paper and is a corrugated board web, and therefore multi-layered. The system 2 shown here is an example of a corrugated board system; however, the following explanations apply analogously to other systems 2 and webs 4. In any case, the processing of the web 4 described here takes place after the print image 6 has been printed, i.e., a preprint is present during processing.

[0031] The web 4 is fed to a cutting / creasing unit 14 of the system 2, and the cutting / creasing unit 14 processes the web 4 at a number of processing positions 16 (i.e., cutting and / or creasing positions) in the longitudinal direction L. The cutting / creasing unit 14 makes one or more cuts and / or grooves in the web 4. Hereinafter, without loss of generality, it is assumed that there is a cutting and creasing unit 14 with which the web 4 is both cut and creased. The longitudinal direction L corresponds to a conveying direction of the web 4 through the system 2. The processing positions 16 are accordingly those positions along the web 4 at which one or more cuts and / or grooves are made by the cutting / creasing unit 14, which serve to prepare the corrugated board web into individual sheets 26 and to form break, fold or crease edges of the sheets 26 and subsequent sheets 18.

[0032] In the embodiment shown here, the cutting / creasing unit 14 is arranged downstream of a so-called double-facer 20, in which several intermediate products for the corrugated board web are assembled to form the actual corrugated board web. The double-facer 20 also marks the end of a so-called "wet end" 22 of the system 2, to which a so-called "dry end" 24 is attached. This dry end is used to convert the web 4 into individual blanks 26 and finally sheets 18. The cutting / creasing unit 14 is part of the dry end 24. Here, the web 4 is cut into several separate sub-webs (i.e., the blanks 26) by the cutting / creasing unit 14. Downstream of the cutting / creasing unit 14, the system 2 also includes a cross-cutter 28, which cuts the sub-webs in the transverse direction Q, thus dividing them into individual sheets 18. Optionally, a divider 30 is arranged between the cutting / grooving unit 14 and the cross cutter 28.Optionally, a short cross cutter 32 is arranged between the double-facer 20 and the cutting / grooving unit 14.

[0033] Upstream of the cutting / creasing unit 14, the web 4 has an actual width B, also referred to simply as width. The actual width B is the real width of the web 4 and is measured in the transverse direction Q. As part of the process, an actual dimension I is measured for the actual width B, and from this, together with a target dimension S, a scaling factor F is determined to adjust the processing positions 16 to the actual width I. The cutting / creasing unit 14 is then adjusted according to the scaling factor F so that the processing positions 16 are adapted to the printed image 6. This is illustrated in the flowchart of the Fig. 2 The cutting / creasing unit 14 is therefore adjustable and is automatically set according to the actual width B (using the actual dimension I) so that the cuts and / or creases always fit the printed image 6 exactly. For this purpose, the processing positions 16, i.e., the layout of the cuts and / or creases, are scaled by the scaling factor F. A variation in the actual width, and thus an otherwise unintended scaling of the printed image 6, is therefore compensated for by a corresponding scaling of the cutting / creasing unit 14.

[0034] Overall, the processing positions 16 of the cutting / creasing unit 14 are adjusted to the actual print image 6, whereby any resulting deviation of the actual dimensions of the print area 26 from the specified target dimension S from the order data 34 is accepted. This contrasts with the reverse approach of adjusting the print image 6 to fixed processing positions 16, i.e., positioning the cuts and / or creases exactly as specified in the order data 34. In this case, the cuts and / or creases would regularly no longer match the print image 6. This is exemplified in the Fig. 3 - 5 The illustration shows web 4 and processing positions 16 in a top view of web 4. There, web 4 is divided into five identical sub-webs by the cutting / creasing unit 14; that is, the printed image 6 has five identical images side by side in the transverse direction Q, which must be separated accordingly. A specific width is specified as the target dimension S in the order data 34. This ideal case is shown in Fig. 3 As shown, the target dimension S matches the print image 6. However, on its journey to the cutting / creasing unit 14, web 4 experiences an unexpected dimensional change; for example, web 4 shrinks less than expected and now has an actual width B that is larger than the target width resulting from the target dimension S (and possibly an anticipated dimensional change that does not actually occur). This is shown in Fig. 4 This is shown and, when cut, results in parts of the image of one panel 26 lying on the adjacent panel 26. For example, if one considers a single sheet 18 already formed into a folding box, the printed image 6 appears shifted relative to the edges and margins of the folding box; that is, the image edge and the cut edge do not align. Since the web 4 is typically as shown in the Fig. 3 - 5 As shown, when the workpiece is guided centrally into the cutting and grooving unit 14, the corresponding error in the transverse direction Q increases outwards, as shown in Fig. 4 This is clearly recognizable. The scaling of the processing positions 16 to the actual printed image 6 described here is achieved by adjusting the cutting / creasing unit 14 accordingly, depending on the scaling factor F and starting from Fig. 4 is then in Fig. 5 As shown, the cuts and grooves there again match the printed image perfectly 6.

[0035] In addition to the described adjustment of the processing positions 16 to the print image 6, an anticipated dimensional change of the web 4 is also taken into account. Accordingly, the process anticipates a dimensional change of the web 4 during its processing within the system 2 and accounts for it by scaling, e.g., enlarging, the print image 6 before printing. This allows the previously described adjustment of the processing positions 16 to the print image 6 to compensate for any variation in the anticipated dimensional change. The anticipated dimensional change is primarily an expected change that does not necessarily occur completely as the web 4 moves through the system 2. Therefore, despite this consideration, the adjustment at the cutting / creasing unit is still necessary. Fig. 4 The situation shown arises. This results from variations compared to the estimated dimensional change. The method described here thus advantageously includes two compensation mechanisms for any dimensional changes of web 4, namely, on the one hand for an estimated dimensional change and on the other hand for an actual dimensional change, specifically a variation (or deviation) compared to the estimated dimensional change. First, the printed image 6 itself is scaled from the outset depending on the anticipated dimensional change; for example, the target dimensions S of the printed image 6 are multiplied by a corresponding scaling factor (not the previously mentioned scaling factor F). The anticipated dimensional change is regularly based on empirical values, which depend on the specific job and the paper used, and typically does not take into account variations in operation, i.e., no dynamic dimensional change, which, for example,This can result from varying web speeds or deviations in drying or moistening the web 4. The method described here specifically addresses such dimensional changes, as the measurement of the actual dimension I captures precisely this type of dimensional change and then automatically compensates for it dynamically and in real time by scaling the processing positions 16. This results in a two-stage correction: a first, coarse, static correction is performed by adjusting the print image 6 to the anticipated dimensional change; and a second, fine, dynamic correction is performed by adjusting the processing positions 16 as described in the section on . Fig. 5 described and adapted to print image 6.

[0036] The scaling factor F is calculated from the actual dimension I and the target dimension S, e.g., simply as the ratio of actual dimension I to target dimension S, or in another suitable way. The target dimension S is taken from the order data 34 for processing web 5 and is typically specified by the customer. The target dimension S is a measure of what dimensions the individual units 26 or sheets 18 should ultimately have, e.g., simply the sum of the widths of the sub-webs 26, if the actual dimension I is simply the width B of the entire web. The target dimension S also specifies the processing positions 16, which are now scaled in the procedure described here to be adapted to the actual print image 6.

[0037] To ensure the best possible adaptation of the processing positions 16 to the printed image 6, the actual dimension I is measured as close as possible to the cutting / creasing unit 14, e.g., at most 10 m or even at most 1 m upstream of the cutting / creasing unit 14. In principle, various configurations are possible and suitable for the actual dimension I; the essential point is that it allows conclusions to be drawn about the actual width B and thus about the dimensions of the actual printed image 6.

[0038] In a first possible embodiment, the actual dimension I is simply the actual width B of the web 4. The actual dimension I is measured, for example, using web width or web edge detection; for this purpose, Annex 2 includes a corresponding sensor unit 36. In a second possible embodiment, the actual dimension I is a distance between two print features 38 of the print image 6, e.g., as in Fig. 6 shown. In this configuration, the printed image 6 is directly analyzed to detect any dimensional changes in the web 4 and the printed image 6. Which specific printing features 38 are used is initially irrelevant. However, these are positioned as far apart as possible along the width B of the web 4, meaning that the distance between the two printing features 38 in the transverse direction Q should be as large as possible. Fig. 6 the distance is at least 50% of the width B and the two print features 38 are even located on different sub-webs 26, specifically on the two outermost sub-webs 26.

[0039] As printing features 38, all features that are present in the print image 6 are suitable, for example the already mentioned logos 8, decorations 10 and control codes 12 and generally those printing features 38 that are already present and do not need to be printed on separately, for example the control codes 12 for the subsequent cross cutter 28.

[0040] The actual dimension I is determined using two sensors, which simultaneously adjust the cutting / creasing unit 14 relative to the web path. The web path refers to the position of the web 4 relative to the transverse direction Q. The two sensors are part of the sensor unit 36 ​​and serve to track the cutting / creasing unit 14 in order to adapt the processing positions 16 to the general web path, initially independent of any dimensional changes. For this purpose, the web path is measured with the sensors, and then the cutting / creasing unit 14 is correctly positioned in the transverse direction Q based on this measurement. In addition, the actual dimension I is also measured with these two sensors. The sensors are designed accordingly to detect the aforementioned print characteristics 38 or the width B.

[0041] To produce cuts and / or grooves at the machining positions 16, the cutting / grooving unit 14 has several machining bodies 42, for example, as shown in Fig. 7 These processing bodies 42 are arranged along the transverse direction Q and are designed for the mechanical processing of the web 4, in order to introduce cuts and / or grooves into it by a mechanical action. Each processing body 42 has, for example, a pair of rollers with two rollers and each with a cutting blade or a creasing contour. The processing bodies 42 are adjustable relative to each other, and the cutting / creasing unit 14 is adjusted by adjusting the processing bodies 42 relative to each other. In other words, the processing positions 16 are scaled and adapted to the printed image 6 by adjusting the processing bodies 42 accordingly relative to each other, for example, by appropriately increasing or decreasing their distance in the transverse direction Q. Fig. 7The machining bodies 42 are designed for parallel positioning and are adjustable separately for this purpose. The cutting / grooving unit 14 has a separate adjustment mechanism 44 (e.g., each with a spindle) for each of the machining bodies 42, and the adjustment mechanisms 44 can be controlled independently of each other. This contrasts with serial positioning, in which only a single adjustment mechanism is used for several machining bodies 42.

[0042] The system 2 also includes a control unit 46, which is configured to determine the scaling factor F from the actual dimension I together with the target dimension S, in order to then adjust the processing positions 16 to the actual width B as described. The control unit 46 is further configured, as described, to adjust the cutting / creasing unit 14 depending on the scaling factor F such that the processing positions 16 are adapted to the printed image 6. Reference symbol list

[0043] 2 Plant 4 Lane 6 Print Image 8 Logo 10 Decoration 12 Control Code 14 Cutting / Creaking Unit 16 Processing Position 18 Sheet 20 Double Facer 22 Wet End 24 Dry End 26 Sub-web (Partial Web) 28 Cross Cutter 30 Divider 32 Short Cross Cutter 34 Job Data 36 Sensor Unit 38 Print Feature 42 Processing Body 44 Adjustment Mechanism 46 Control Unit BI Actual Width F Scaling Factor II Actual Dimension L Longitudinal Direction Q Transverse Direction S Target Dimension

Claims

1. Method for processing a web (4) which is printed with a print image (6), - wherein the web (4) is fed to a slitting / creasing unit (14) by means of which the web (4) is processed at a number of processing positions (16) in the longitudinal direction (L), - wherein the web (4) has a width (B) upstream of the slitting / creasing unit (14), - wherein an actual dimension (I) for the width (B) is measured, - wherein the slitting / creasing unit (14) is set according to the actual dimension (I) and a target dimension (S) for the width (B) in such a way that the processing positions (16) are adapted to the print image (6), characterized - in that, for producing slits and / or creases, the slitting / creasing unit (14) has multiple machining bodies (42) which are arranged along a transverse direction (Q), that is to say perpendicularly to the longitudinal direction (L), and are adjustable relative to one another, - in that the slitting / creasing unit (14) is set by the machining bodies (42) being adjusted relative to one another.

2. Method according to Claim 1, wherein a dimensional change of the web (4) during the processing thereof is estimated in advance, and is taken into account by the print image (6) being printed in a scaled manner such that a variation of the estimated dimensional change is compensated by adapting the processing positions (16) to the print image (6).

3. Method according to Claim 1 or 2, wherein scaling of the print image (6) is adjusted by regulation in relation to the target dimension (S) according to the actual dimension (I), so that the print image (6) is adapted to the target dimension (S).

4. Method according to one of Claims 1 to 3, wherein the actual dimension (I) is measured at most 10 m upstream of the slitting / creasing unit (14).

5. Method according to one of Claims 1 to 4, wherein the actual dimension (I) is a distance between two printing features (38) of the print image (6).

6. Method according to one of Claims 1 to 5, wherein the actual dimension (I) is the width (B).

7. Method according to one of Claims 1 to 6, wherein the actual dimension (I) is determined by means of two sensors which, at the same time, also set the slitting / creasing unit (14) overall relative to the web course into the slitting / creasing unit (14).

8. Method according to one of Claims 1 to 7, wherein the machining bodies (42) are configured for parallel positioning and, for this purpose, are adjustable separately from one another.

9. Method according to one of Claims 1 to 8, wherein the web (4) is a corrugated-cardboard web.

10. Installation (2) for processing a web (4) which is printed with a print image (6), - having a slitting / creasing unit (14) to which the web (4) is fed in order for said web to be processed at a number of processing positions (16) in the longitudinal direction (L), - wherein the web (4) has a width (B) upstream of the slitting / creasing unit (14), - having a sensor unit (36) which is configured for measuring an actual dimension (I) for the width (B), - having a control unit (46) which is configured to set the slitting / creasing unit (14) according to the actual dimension (I) and a target dimension (S) for the width (B) in such a way that the processing positions (16) are adapted to the print image (6), characterized - in that, for producing slits and / or creases, the slitting / creasing unit (14) has multiple machining bodies (42) which are arranged along a transverse direction (Q), that is to say perpendicularly to the longitudinal direction (L), and are adjustable relative to one another, - in that the slitting / creasing unit (14) is set by the machining bodies (42) being adjusted relative to one another.