DE102023131127A1 - Corrugated board plant, method for operating a corrugated board plant and method for converting a corrugated board plant - Google Patents

Abstract

The invention relates to a corrugated board plant (2) which extends in a longitudinal direction (L) from a rear side (4) to a front side (6), which has a wet end (8) which begins at the rear side (4), and a dry end (10) which ends at the front side (6), which is designed to produce corrugated board from a plurality of paper webs (12, 12a), which has a printer (28) for printing one of the paper webs (12) so that this then forms a printed paper web (12a) with a printed side (30), which has a drying section (32) for the printed paper web (12a), wherein the drying section (32) begins at the printer (28). The invention further relates to a method for operating a corrugated board plant (2) and to a method for converting an original corrugated board plant into a corrugated board plant (2).

Description

The invention relates to a corrugated board plant, a method for operating such a corrugated board plant and a method for converting a corrugated board plant.

A corrugator is used to produce corrugated board. Several paper webs are unwound from a respective unwinder and joined together to form a single corrugated board web. For this purpose, one of the paper webs is typically corrugated with a fluting roller and then glued to two non-corrugated paper webs. Multi-layer corrugated board webs with more than one corrugated paper web are also possible. The finished corrugated board web can optionally be cut into individual pieces by the corrugator, i.e., cut into individual pieces. It is also advantageous to integrate a printer into the corrugator to print the paper webs according to the order and requirements.

Corrugated board systems with integrated printers face the problem that the printed image on the paper web that was printed using the printer must be sufficiently dry before the printed paper web can be processed further. For example, a single paper web is printed within the corrugator and then joined to other paper webs in a double-facer to form the corrugated board web. To do this, the paper web must pass through a preheater and a gluing unit and is generally in contact with corresponding rollers at various times. If the printed image is not sufficiently dried during further processing of the printed paper web, the print image will smear. This not only reduces the quality of the print image, but also potentially contaminates the system stations of the corrugator and their individual components, e.g. rollers, with ink.

In principle, it is possible to design the print image and the production process of the corrugated board web in such a way that smearing does not occur on a given corrugator. For example, a small amount of ink is printed, which then dries quickly, or the conveying speed through the corrugator is reduced accordingly, allowing more time for drying before further processing. However, this results in limitations on the performance and flexibility of the corrugator.

Against this background, it is an object of the present invention to provide an improved corrugated board system that is as flexible and efficient as possible. The corrugated board system should be able to process as many different jobs as possible at the maximum possible speed. To this end, the drying of the printed image on the printed paper web should be improved in particular in order to be able to print images with a large amount of ink applied without subsequent smearing and to be able to operate the corrugated board system at the highest possible conveying speed. Furthermore, a correspondingly suitable method for operating such a corrugated board system and a method for converting a corrugated board system should be specified.

The object is achieved by a corrugated board plant having the features according to claim 1, a method having the features according to claim 14, and a method having the features according to claim 15. Advantageous embodiments, further developments, and variants are the subject of the dependent claims. The statements made in connection with the corrugated board plant also apply mutatis mutandis to the two methods, and vice versa. If one or more steps of a method (in particular the method for operation) are implicitly or explicitly stated below, suitable embodiments for the corrugated board plant result from the fact that it is designed to carry out one or more of these steps.

A key aspect of the present invention is, in particular, the longest possible drying section directly downstream of a printer in a corrugated board plant. This makes it possible to achieve sufficient drying even with high conveying speeds and heavy ink application, thus avoiding the aforementioned disadvantages of incomplete drying. A particularly important aspect is to integrate this drying section as optimally as possible into a corrugated board plant layout. Firstly, the overall size of the corrugated board plant should be limited by the surrounding dimensions (e.g., the length or height of a factory hall). Secondly, the conversion of existing corrugated board plants should be as cost-effective as possible. Existing plant layouts are typically optimized for minimal space requirements, so adding additional plant stations, especially a printer and a subsequent drying section, is not readily possible. Thirdly, the drying section should be as easily accessible as possible, in particular to make threading the printed paper web as easy as possible. This is particularly important when switching from a job without printing to one with printing and vice versa.

The corrugator according to the invention extends in a longitudinal direction from a rear side to a front side. The corrugator has a wet end, which begins at the back, and a dry end, which ends at the front side. The back side is therefore a beginning of the corrugator, and the front side is its end. The corrugator is designed to produce corrugated board from multiple paper webs. The paper webs are each unwound from an unwinding unit, conveyed through the corrugator, and processed in the process. Each unwinding unit is a station in the corrugator. In the wet end, the paper webs are assembled to form the corrugated board web. For this purpose, the corrugator has one or more single-facers, a preheater, a gluing unit, and a double-facer. In the dry end, which begins downstream of the double-facer, the corrugated board web is finished as required using suitable stations. The exact design of the dry end is not important in this case. The longitudinal direction corresponds to a general conveying direction through the corrugator, i.e. the paper webs and the corrugated board web are generally conveyed in the longitudinal direction, but are deflected locally as required using appropriate deflection elements.

In the context of the present application, the terms "front/in front of/in front of" and similar terms, as well as "rear/behind/behind" and similar terms, are understood spatially and relative to the longitudinal direction, i.e., "front" and similar terms mean in the direction of the front, and "rear" and similar terms mean in the direction of the rear. In other words, a component A of the corrugator is located behind a component B of the corrugator if component A is closer to the rear than component B. This means that, viewed opposite to the longitudinal direction, component A is located behind component B. The same applies to "in front of." The longitudinal direction points from the rear to the front; the opposite direction is accordingly referred to as "opposite to the longitudinal direction." The terms "below/below/below" and similar terms, as well as "above/above/above" and similar terms, are to be understood as directional information perpendicular to the longitudinal direction and perpendicular to a surface (e.g., floor level) on which the corrugator is installed. A component A of the corrugator is located above a component B of the corrugator if component A is further away from the installation area than component B, but in particular both components are positioned at least at a similar longitudinal position when viewed in the longitudinal direction. The same applies to "below" and similar. The terms "upstream" and "downstream", however, are understood relative to a respective paper web or relative to the corrugator web. In other words: a component A of the corrugator is located downstream of a component B of the corrugator if one of the paper webs first passes through component B and then component A. Component A can be located in front of or behind component B, i.e., the paper web is guided from component B to component A either in the longitudinal direction or counter to the longitudinal direction. The reverse applies to the term "upstream". Components A and B are, for example, system stations of the corrugator or individual components thereof. The above explanations also apply to the description of the figures below.

The corrugated board machine has a printer for printing on one of the paper webs, so that this then becomes a printed paper web with one printed side. During printing, ink is printed on one side of the paper web, namely the side that will then be printed, thereby creating a print image. This side is then the printed side, while the other, opposite side of the paper web typically remains unprinted. The printer is one of several stations in the corrugated board machine. The printer is preferably an inkjet printer. The printer is preferably a monochrome printer, i.e. it only prints a single color. An inkjet printer and a monochrome printer are particularly compact. However, a monochrome printer is not mandatory; in principle, a printer with multiple colors can also be used.

The corrugated board line also has a drying section for the printed paper web. The paper web that is printed with the printer is then conveyed through the drying section, so that the printed paper web dries along the drying section; this occurs in particular before further processing in another system station and in any case before the printed side comes into contact with a component of a system station. For this purpose, the mere additional dwell time created by the drying section (passive drying) is typically sufficient. Optionally, the corrugated board line has a system station arranged along the drying section for treating, handling, or inspecting the paper web. For example, the drying section has a drying unit as a system station for additional drying of the printed paper web (active drying). For this purpose, the drying unit has, for example, one or more IR radiators, contact surface heaters, and/or hot air dryers. The drying unit is optionally used to precondition the printed paper web for further processing in the corrugated board line, e.g., to achieve a specific shrinkage.

The drying section is also referred to as the penetration section because drying is characterized by the ink penetrating the paper web. Ink that does not penetrate the paper web (incomplete drying) potentially leads to smearing of the print image downstream of the printer.

The drying section begins at the printer (more precisely, at one of the printer's print heads). This makes the drying section as compact as possible. The drying section includes a detour for the printed paper web on its further path through the corrugator, particularly on its way to the next station.

The drying section preferably has a reverse section which leads towards the back side, so that the printed paper web is guided on the reverse section against the longitudinal direction. This is also referred to as reverse guidance. The printed paper web is therefore not guided downstream of the printer in the general conveying direction (longitudinal direction) to the next system station, but first in the opposite direction, namely backwards, i.e. against the longitudinal direction and behind the printer. This creates a particularly long drying section. A key aspect in particular is the reverse guidance of the printed paper web, which takes place along the reverse section, as this creates additional installation space within the corrugator, which enables the drying section to be extended.

Alternatively or in addition to the reverse guide, the drying section, in an advantageous embodiment, has a vertical section which leads upwards or downwards with respect to the longitudinal direction, i.e. in particular perpendicularly or generally at an angle greater than 0° to the longitudinal direction, wherein the angle is preferably at least 60° (vertical direction). This is then referred to as "vertical guide" analogous to the reverse guide. Here, too, the printed paper web downstream of the printer is initially not guided in the general conveying direction (longitudinal direction) to the next system station, but in a vertical direction, i.e. upwards or downwards. This also creates an advantageously long drying section. The vertical guide, in particular, uses installation space in front of or behind the printer for an extended drying section. Instead of simply passing the paper web on from the printer, at least the height of the printer is still used as a drying section.

The reverse guide and the vertical guide are generally also referred to as detour guides. What is particularly important here is that the paper web downstream of the printer is not guided as directly as possible to the next system station, but via a detour, namely the reverse section and/or the vertical section of the drying section. The drying section therefore contains a detour for the printed paper web and does not lead directly to the next system station. A design in which the drying section has both a reverse section and a vertical section is also particularly useful. A design in which the reverse section adjoins the vertical section is particularly useful, so that the paper web is first output from the printer, then guided upwards or downwards (preferably: upwards) and then backwards. A combination of several vertical sections and/or several reverse sections is also possible.

The printed paper web is output from the printer in the longitudinal direction, i.e., towards the front. From here, the printed paper web is then deflected first upwards (or downwards) by means of a suitable (first) deflection element, and then towards the back, i.e., backwards, by means of a (second) deflection element. The second deflection element marks the end of the vertical section and the beginning of the reverse section, and in particular has no contact with the printed side, but only with the opposite, unprinted side (as does the first deflection element). Alternatively, the printed paper web is output from the printer directly against the longitudinal direction, i.e., backwards. The reverse section then begins directly at the printer or its print head; alternatively or additionally, a vertical section is passed through as described. Regardless of the direction in which the printer outputs the printed paper web, the drying section also has an end, which is marked by a (third) deflection element, with which the printed paper web is deflected again, in particular back to the front. This third deflection element is in particular in contact with the printed side. The return section also ends at this third deflection element. From the printer to the end of the return section, the printed side, however, remains untouched and has the appropriate time (dwell time) to dry up to this point.

The aforementioned deflection elements preferably have one or more deflection rollers for deflecting the printed paper web. In an advantageous embodiment, one or more deflection elements are heated, so that the printed paper web is additionally heated and thus dried by the respective deflection element.

In a preferred embodiment, the drying section is defined by beginning at a print head of the printer and ending at a deflection element of the corrugator, and by leaving the printed side untouched between the print head and the deflection element. Instead, only the non-printed side is touched—if necessary. Another advantageous embodiment is one in which the deflection element that first comes into contact with the printed side downstream of the printer has a special non-stick coating that reduces the ink's adhesion to the deflection element (compared to a deflection element without such a non-stick coating).

The drying section is generally located downstream of the printer and, due to the reverse section, preferably guides the printed paper web behind the printer. The next station (e.g., a preheater) of the corrugator is located downstream of the drying section. The "next station" here means that there is no further station between it and the drying section. The next station is preferably located upstream of the printer, or alternatively, behind it.

The following, without limiting its generality, assumes a configuration in which the printer is arranged in front of an unwind unit of the corrugated board system and behind a preheater of the corrugated board system. No further system stations are arranged between the unwind unit and the printer, or between the printer and the preheater. A paper web is unwound using the unwind unit, which is fed to the printer and printed there. The now printed paper web is then fed via the drying section to the preheater. The unwind unit, the printer and the preheater are arranged in particular on a common assembly level, but the drying section is located in a different assembly level, in particular in an assembly level above the printer and optionally also above the unwind unit. Depending on the specific configuration of the corrugated board system and the arrangement of the printer therein, other arrangements are suitable as alternatives to the preferred arrangement described above. For example, the printer is arranged at the rear of the corrugated board system and there, for example, behind or above the unwind unit that is closest to the rear.

Downstream of the preheater, the paper webs are fed into a gluing unit of the corrugator. The preheater serves to precondition the paper webs before glue is applied in the gluing unit. Still within the gluing unit or downstream of it, the paper webs are then pressed together to form the corrugated board web and fed into a heating section (i.e., the double facer). The point at which the paper webs are pressed together to form the corrugated board web is also referred to as the gluing point. Similarly, the point at which ink is printed onto the paper web in the printer is referred to as the printing point. The printing point is fundamentally defined by the printer's print head. The entire drying section, or at least the reverse section, is preferably located above an imaginary connecting line between the printing point and the gluing point.

By guiding the paper web backwards with the reverse section and guiding it in the vertical direction with the vertical section, the path for the printed paper web to the next system station is extended. A certain drying path is automatically created in principle because the printed paper web has to travel a certain distance from the printer to the next system station of the corrugator. However, since a system layout that is as compact as possible is typically chosen, the printer is usually positioned as close as possible to the next system station, so that the path in between is as short as possible and is only suitable to a limited extent as a drying path. In the sense of the invention described here, the drying path is therefore deliberately extended by means of a detour, resulting in a longer drying path (penetration path). Although the next system station is still expediently positioned as close as possible to the printer, the drying path is not the shortest possible path from the printer to the next system station. Rather, the drying section described here deliberately creates a detour for the printed paper web, namely a detour upwards/downwards and/or backwards, in order to achieve the longest possible drying section. This correspondingly extends the dwell time until further processing of the printed paper web.

The reverse section is preferably at least 0.5 m long (measured along the paper web), more preferably at least 5 m, and particularly preferably at least 10 m long. This only describes the length of the reverse section in one direction; the entire drying section, measured along the paper web, is usually longer. Specifying an upper limit for the length of the reverse section is not necessarily useful; however, it is typically sufficient if the reverse section is at most 20 m long, thus corresponding to approximately 1/5 to 1/10 of the total length of the corrugator.

In an advantageous embodiment, the drying section is further extended by being folded, with several sections on which the paper web is guided alternately towards the back (towards the rear) and towards the front (towards the front). Those sections on which the paper web is guided towards the back then each constitute a backward section, as already described. The remaining sections are analogously referred to as forward sections. Depending on the design, this results in a spiral or meandering course of the paper web along the drying section. For example, the printed paper web is output from the printer towards the front with the print image facing downwards and, downstream of the printer, is initially guided along a first backward section towards the back by a deflection element which engages the unprinted side. The printed paper web is then deflected back towards the front along a first forward section by means of a further deflection element which also engages the unprinted side. This concept can, in principle, be repeated several times depending on the available installation space, so that the paper web alternates between several reverse sections and, if necessary, several forward sections. Each deflection element always engages only the non-printed side. Finally, however, the printed paper web must be guided to the next system station by means of at least one final deflection element, which then marks the end of the drying section. This final deflection element then inevitably engages the printed side of the paper web.

The corrugator, in particular, has a bridge. The bridge serves to temporarily store semi-finished products for the corrugated board web, namely products from one or more single-facers, each of which produces a corrugated paper web and joins it to a non-corrugated, flat paper web to form a so-called half-wave. The bridge is arranged, in particular, in an assembly plane above the assembly plane of the printer.

In a preferred embodiment, the printer is arranged below the bridge. The printer serves in particular to print a so-called lamination web, i.e., the paper web that is subsequently assembled with one or more half-flutes to form the corrugated board web and then forms an outer layer of the corrugated board web. Accordingly, the unwinding unit, which delivers the paper web to the printer, is also arranged below the bridge. The reverse section is then expediently arranged within the bridge or in a space between the printer and the bridge. This allows the drying section to be integrated into the corrugator in a particularly space-saving manner. This also prevents the drying section from requiring additional installation space in the printer's assembly plane, so that the printer and the system stations upstream and downstream (e.g., unwinding unit and preheater) are positioned particularly close to the printer. The overall length of the corrugator is therefore not affected. Rather, the drying section, especially at least its reverse section, is placed in an assembly plane above the printer. This assembly level either corresponds to the assembly level of the bridge, so that the reverse section is located within the bridge, or an additional assembly level for the reverse section is inserted between the printer and the bridge, particularly by raising the bridge accordingly. This increases the height of the corrugator but not its overall length.

The bridge expediently has a walkway from which the reverse section is accessible, in particular for manually threading the printed paper web into the reverse section. The walkway runs in particular laterally along the bridge in the longitudinal direction. The walkway originally serves in particular as access to the bridge in order to be able to carry out maintenance or the like on it if necessary. Advantageously, the reverse section is now also accessible from the walkway, in particular both are on the same level. This then makes it easy to thread the printed paper web into the reverse section from the walkway. This is particularly relevant in designs in which the printer has a height that is greater than a person, e.g. 2 m to 2.5 m, so that threading from the mounting level (floor level) of the printer is difficult.

The corrugated board machine suitably includes a splicer. The splicer is, in particular, part of an unwinding unit, which also includes two unwinders. A paper web is alternately unwound from the unwinders, and the splicer joins the end of one paper web to the beginning of the other during a roll change. In a suitable embodiment, the splicer is arranged above the two unwinders.

In an advantageous embodiment, the splicer is arranged behind the printer, viewed against the longitudinal direction, and the rear section now extends over the splicer; the The above statements regarding the return section above the printer apply analogously. In particular, if necessary, the aforementioned bridge above the splicer is also raised analogously in order to increase the aforementioned gap accordingly perpendicular to the longitudinal direction. In this embodiment, the paper web that is printed with the printer downstream of the splicer is also output via the splicer. By extending the return section beyond the splicer, the length of the return section is increased accordingly and thus also the dwell time (at a constant conveying speed) of the printed paper web for drying.

The additional possible installation space above the splicer, i.e. in particular the space between the splicer and the bridge, is advantageously used as an alternative or in addition to the extension of the return section described above to accommodate a system station for treating, inspecting or handling the paper web before it enters the printer and is printed there. The system station is, for example, a pre-treatment unit. Analogous to the return section, the system station is then expediently arranged above the splicer. In a corresponding embodiment, the splicer then outputs the paper web that will be printed with the printer, and the corrugator has a system station arranged above the splicer for treating the paper web upstream of the printer. Alternatively, the system station is not arranged above the splicer, but before or after the splicer and in particular in the immediate vicinity of the splicer. This then advantageously uses corresponding installation space before or after the splicer. The paper web leaves the splicer, is guided downstream to the system station, where it is pretreated, and then further downstream to the printer for printing. Analogous to the change of assembly level from the printer to the return section, the paper web also changes assembly level from the splicer to the system station, and the assembly level is changed again from the system station to the printer. This means that the overall length of the corrugator remains unchanged. The system station above the splicer is suitably a unit for temperature control, moistening, primer application, corona pretreatment, edge trimming, web inspection, web tension control, lateral control, or the like, or a combination thereof.

Alternatively or in addition to the system station above the splicer, in a suitable embodiment, a system station is arranged along the drying section, preferably along the reverse section and/or along the vertical section and/or above the printer. The statements regarding the system station above the splicer apply accordingly to the system station along the drying section.

The return section is expediently adjustable in length, i.e. it has an adjustable length. This advantageously allows the dwell time (and thus the extent of drying) to be adjusted, while the adjustable length is also advantageous for threading the printed paper web into the return section. The length of the return section is controlled, for example, depending on the result of a print image inspection. In this case, the printed paper web is examined inside or downstream of the drying section using a web inspection unit to determine whether the print image is smeared or not. If the print image is smeared, the length is increased; otherwise it is maintained or reduced. For example, a drying unit is then arranged along the drying section in such a way that, depending on the length of the return section, the drying section only extends partially into the drying unit, and the paper web is dynamically moved into and out of a drying area of the drying unit.

In a suitable embodiment, the return section has a dancer and is therefore length-adjustable for setting a residence time (i.e. drying time) for drying the printed paper web. The dancer is in particular a deflection element as already described above. The dancer is characterized in particular in that it can be moved to adjust the length of the return section, in particular in and against the longitudinal direction. By moving the dancer against the longitudinal direction, the return section and the residence time are then extended and, conversely, by moving it in the longitudinal direction, they are correspondingly shortened. However, the dancer does not necessarily have to be movable along the longitudinal direction, but can in principle also be moved alternatively or additionally at an angle or perpendicular to this, i.e. up and down.

In an advantageous development, the dancer can be guided to a front of the printer for threading the printed paper web into the reverse section. The dancer can therefore be moved forward, in particular, to a threading position. The threading position is, in particular, a final position for the dancer, so that a minimum length of the reverse section is simultaneously set in the threading position. The threading position is expediently located in front of the front of the printer, so that the dancer is then easily accessible from in front of the printer.

Analogously, the vertical section is alternatively or additionally adjustable in length; the above statements apply accordingly.

In the method according to the invention for operating a corrugated board plant (operating method), the plant extends in a longitudinal direction from a rear side to a front side, has a wet end which begins at the rear side and a dry end which ends at the front side, and is designed to produce corrugated board from several paper webs. The corrugated board plant furthermore has a printer with which one of the paper webs is printed so that this then becomes a printed paper web with a printed side. The corrugated board plant additionally has a drying section for the printed paper web, wherein the drying section begins at the printer and wherein the drying section has a return section which leads in the direction of the rear side so that the printed paper web is guided on the return section counter to the longitudinal direction. The statements regarding the corrugated board plant also apply accordingly to the method.

Another method according to the invention serves to convert an original corrugated board plant to a corrugated board plant as described above (conversion method). The original corrugated board plant does not necessarily have a printer and in any case does not have a drying section; rather, one is retrofitted as part of the method. However, the original corrugated board plant has a bridge, below which a printer is or is arranged. As part of the method, the bridge is now raised so that an intermediate space between the printer and the bridge is enlarged, and a rear section of a drying section is then arranged in the intermediate space for drying a paper web printed with the printer. The statements regarding the corrugated board plant and the method for operating such a plant also apply accordingly to the conversion method.

• 1 eine Wellpappenanlage,
• 2 einen Ausschnitt der Wellpappenanlage aus 1,
• 3 ausschnittsweise eine Variante der Wellpappenanlage aus 1,
• 4 ausschnittsweise eine weitere Variante der Wellpappenanlage aus 1,
• 5 ausschnittsweise eine weitere Variante der Wellpappenanlage aus 1,
• 6 ausschnittsweise eine weitere Variante der Wellpappenanlage aus 1.

In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In each case, schematically:

• 1 a corrugated board plant,
• 2 a section of the corrugated board plant 1 ,
• 3 a section of a variant of the corrugated board plant from 1 ,
• 4 a section of another variant of the corrugated board plant from 1 ,
• 5 a section of another variant of the corrugated board plant from 1 ,
• 6 a section of another variant of the corrugated board plant from 1 .

In 1 an embodiment of a corrugated board plant 2 according to the invention is shown, 2 shows a section of it in detail. The corrugated board plant 2 extends in a longitudinal direction L from a back side 4 to a front side 6. The corrugated board plant 2 has a wet end 8, which begins at the back side 4, and a dry end 10, which ends at the front side 6. The corrugated board plant 2 is designed to produce corrugated board from a plurality of paper webs 12. The paper webs 12 are each unwound from an unwind unit 14, conveyed through the corrugated board plant 2 and processed in the process. The unwind units 14 are each plant stations 16 of the corrugated board plant 2. In the wet end 8, the paper webs 12 are assembled to form the corrugated board web 18. For this purpose, the corrugated board plant 2 has one or more single facers 20, a preheater 22, a gluing unit 24 and a double facer 26. In the dry end 10, which begins downstream of the double facer 26, the corrugated board web 18 is finished as needed using suitable system stations 16 (not shown). However, the exact configuration of the dry end 10 is not important in this case. The longitudinal direction L corresponds to a general conveying direction through the corrugator 2, i.e., the paper webs 12 and the corrugated board web 18 are generally conveyed in the longitudinal direction L, but are locally deflected as needed using appropriate deflection elements.

The corrugator 2 has a printer 28 for printing one of the paper webs 12, so that this then becomes a printed paper web 12a with a printed side 30. The other, opposite side of the paper web 12a typically remains unprinted.

The corrugated board system 2 further comprises a drying section 32 for the printed paper web 12a. The paper web 12 that is printed with the printer 28 is subsequently conveyed through the drying section 32, so that the printed paper web 12a dries along the drying section 32; this occurs in particular before further processing in another system station 16 and in any case before contact of the printed side 30 with a component of a system station 16. For this purpose, the mere additional dwell time generated by the drying section 32 (passive drying) is typically sufficient. Optionally, the corrugated board system 2 comprises a system station 16, which is arranged along the drying section 32, for the treatment, handling, or inspection of the paper web. 2 It is shown by way of example that the drying section 32 has a drying unit 34 for additional drying drying of the printed paper web 12a (active drying).

The drying section 32 begins at the printer 28 (more precisely: at a print head 36 of the printer 28).

In the illustrated embodiment, the drying section 32 has a vertical section 37 and a reverse section 38. The vertical section 37 extends upwards (alternatively: downwards) relative to the longitudinal direction L, i.e., in particular perpendicularly or generally at an angle greater than 0° and here even at least 60° to the longitudinal direction L. The reverse section 38 adjoins the vertical section 37 and extends toward the rear side 4, so that the printed paper web 12a is guided on the reverse section 38 counter to the longitudinal direction L. This is also referred to as reverse guidance. Accordingly, the printed paper web 12a is not guided further downstream of the printer 28 in the general conveying direction (longitudinal direction L) to the next system station 16, but first in the opposite direction, namely backwards, i.e., counter to the longitudinal direction L and behind the printer 28.

In the exemplary embodiment, both a vertical section 37 and a reverse section 38 are shown, but in principle it is also possible to have a design with only a vertical section 37 or only a reverse section 38, depending on the orientation of the printer 28 and the direction in which it outputs the paper web 12a.

In the illustrated embodiment, the printed paper web 12a is output by the printer 28 in the longitudinal direction L, i.e., forwards, and from there, by means of a suitable (first) deflection element 39, first upwards (or downwards), then deflected by means of a (second) deflection element 40 toward the rear side 4, i.e., backwards. This deflection element 40 marks an end of the vertical section 37 and also a beginning of the reverse section 38 and has no contact with the printed side 30, but only with the opposite, unprinted side. Alternatively, the printed paper web 12a is output by the printer 28 directly opposite the longitudinal direction L, i.e., backwards. The reverse section 38 then begins directly at the printer 28 or its print head 36 (not shown). Alternatively or additionally, a vertical section 37 is provided (also not shown). Independently of this, the drying section 32 also has an end which is marked by a (third) deflection element 42, with which the printed paper web 12a is deflected again, in this case again forward. 2 The return section 38 also ends at the deflection element 42. This deflection element 42 also has contact with the printed side 30. From the printer 28 to the end of the return section 38, however, the printed side 12a remains untouched.

The deflection elements 39, 40, 42 have one or more deflection rollers for deflecting the printed paper web 12a. Optionally, one or more deflection elements 39, 40, 42 (or other 2 not explicitly designated deflection elements) so that the printed paper web 12a is additionally heated by means of the respective deflection element 39, 40, 42 and thereby dried.

In the present case, the drying section 32 is defined by the fact that it begins at the print head 36 of the printer 28 and ends at the deflection element 42, and that the printed side 30 remains untouched between the print head 36 and the deflection element 42. Instead, only the non-printed side of the paper web 12a is touched—if necessary. Optionally, the deflection element 42, which first comes into contact with the printed side 30 downstream of the printer 28, has a special non-stick coating that reduces the adhesion of the ink to the deflection element 42.

The drying section 32 is generally arranged downstream of the printer 28 and guides the printed paper web 12a first upwards due to the vertical section 37 and, due to the reverse section 38, behind the printer 28. A next system station 16 (here the preheater 22) is arranged downstream of the drying section 32. The next system station 16 is in the 1 and 2 spatially arranged in front of the printer 28, alternatively behind it (not shown).

Without limiting its generality, the following assumes the embodiment shown in the figures, in which the printer 28 is arranged in front of an unwinding unit 14 and behind a preheater 22. No further system stations 16 are arranged between the unwinding unit 14 and the printer 28, or between the printer 28 and the preheater 22. A paper web 12 is unwound by the unwinding unit 14, which is guided to the printer 28 and printed there. The now printed paper web 12a is then guided via the drying section 32 to the preheater 22. The unwinding unit 14, the printer 28 and the preheater 22 are arranged in a common assembly plane M1, but the drying section 32 is located in a different assembly plane M2, in the present case in an assembly plane M2 above the printer 28 and also above the unwinding unit 14. As an alternative to the position of the printer 28 shown, alternative positions A for the printer 28 are also possible, two of which are shown in 1 These alternative positions A shown are located on the rear 4 of the corrugated board system 2, accordingly the printer 28 can be positioned in the mounting plane M1 at the rear 4 or in a mounting plane M2, M3 above and here above the unwinding unit 14 positioned furthest to the rear.

Downstream of the preheater 22, the paper webs 12, 12a are fed into the gluing unit 24, where the preheater 22 serves for preconditioning. Still within the gluing unit 24 or downstream of it, the paper webs 12, 12a are then pressed together to form the corrugated cardboard web 18 and fed into a heating section (i.e., the double-facer 26). The point at which the paper webs 12, 12a are pressed together to form the corrugated cardboard web 18 is also referred to as the gluing point 44. Similarly, the point at which ink is printed onto the paper web 12 in the printer 28 is referred to as the printing point 46. The entire drying section 32, but at least the reverse section 38, is now located above an imaginary connecting line 48 between the printing point 46 and the gluing point 44. In the embodiment shown, the reverse section 38 is at least 0.5 m and also at least 5 m long (measured along the paper web 12a).

In 3 a variant is shown in which the drying section 3 is further extended by being folded, with several sections 38, 50, on which the paper web 12a is guided alternately in the direction of the back 4 (to the rear) and in the direction of the front 6 (to the front). Those sections 38 on which the paper web 12a is guided in the direction of the back 4 are then each a backward section 38, as already described. The remaining sections 50 are analogously each referred to as a forward section 50. This results in a spiral or meandering course of the paper web 12a along the drying section 32, depending on the design. For example, as in 3 shown - the printed paper web 12a is output from the printer 38 forwards with the print image facing downwards and is guided downstream of the printer 28, initially along a first backward section 38 in the direction of the rear side 4 by a deflection element 40, which engages the unprinted side 30. Then, the printed paper web 12a is deflected back towards the front side 6 along a first forward section 50 by means of a further deflection element, which also engages the unprinted side 30. This concept can basically be repeated several times depending on the available installation space (in 3 This is repeated once, so that a total of two reverse sections 38 are formed), so that the paper web 12a alternately passes through several reverse sections 38 and, if necessary, also several forward sections 50. In this case, a respective deflection element always only acts on the non-printed side 30. Finally, however, the printed paper web 12a must be guided to the next system station 16 by means of at least one final deflection element 42, which then marks the end of the drying section 32. This final deflection element 42 then necessarily acts on the printed side 30 of the paper web 12a.

The corrugator 2 has a bridge 52. The bridge 52 serves to temporarily store semi-finished products 12b for the corrugated board web 18, namely products from one or more single facers 20, each of which produces a corrugated paper web and joins it to a non-corrugated, flat paper web to form a so-called half-wave. The bridge 52 is arranged in an assembly plane M2 above the assembly plane M1 of the printer 28.

In the embodiment shown here, the printer 28 is arranged below the bridge 52. The printer 28 serves in this case to print a so-called lamination web, i.e. the paper web 12 which is then subsequently assembled with one or more half-waves to form the corrugated cardboard web 18 and then forms an outer layer of the corrugated cardboard web 18. Accordingly, the unwinding unit 14, which delivers the paper web 12 to the printer 28, is also arranged below the bridge 52. The return section 38 is now arranged within the bridge 52 or in an intermediate space 54 between the printer 28 and the bridge 52. The drying section 32, specifically at least its return section 38, is placed in an assembly plane M2 above the printer 28. This assembly plane M2 corresponds either to the assembly plane M2 of the bridge 52 (as in 2 shown), so that the rear section 38 lies in the bridge 52, or an additional mounting level M3 for the rear section 38 is inserted between the printer 28 and the bridge 52 by raising the bridge 52 accordingly. This is exemplified in 4 This increases the height of corrugator 2, but not its overall length.

The bridge 52 shown here has a walkway 56, from which the reverse section 38 is accessible for manually threading the printed paper web 12a into the reverse section 38. The walkway 56 runs laterally along the bridge 52 in the longitudinal direction L. The walkway 56 originally serves as access to the bridge 52 in order to be able to carry out maintenance or the like thereon if necessary. From the walkway 56, the reverse section 38 is now also accessible, in 2 Both are on the same level, making it possible to see the printed paper web 12a into the reverse section 38. This is e.g. in the 2 shown embodiment, in which the printer 28 has a height 58 which is greater than a person, here approximately 2 m to 2.5 m, so that threading from the mounting level M1 (floor level) of the printer 28 is difficult.

The corrugated board machine 2 further comprises a splicer 60. The splicer 60 is part of an unwinding unit 14, which also comprises two unwinders 62. A paper web 12 is alternately unwound from the unwinders 62; during a roll change, the splicer 60 connects the end of one paper web 12 to the beginning of the other paper web 12. In the exemplary embodiment shown here, the splicer 60 is arranged above the two unwinders 60.

In the present case, the splicer 60 is arranged behind the printer 28, viewed opposite to the longitudinal direction L, and the rear section 38 now extends beyond the splicer 60; the above statements regarding the rear section 38 above the printer 28 apply analogously. 4 the aforementioned bridge 52 is raised above the splicer 60 in order to enlarge the aforementioned gap 54 perpendicular to the longitudinal direction L. Via the 2 to 6 The paper web 12 that is printed downstream of the splicer 60 with the printer 28 is also output from the splicer 60 shown. By extending the return section 38 beyond the splicer 60, the length of the return section 38 is increased accordingly and thus also the residence time of the printed paper web 12a for drying.

The additional possible installation space above the splicer 60, ie the space 54 between the splicer 60 and the bridge 52, is used alternatively or in addition to the above-described extension of the reverse section 38 to accommodate a system station 16 for treating, examining or handling the paper web 12 before it enters the printer 28 and is printed there. An embodiment of this is shown in 5 shown. The system station 16, for example, is a pretreatment unit. The paper web 12 leaves the splicer 60, is guided downstream into the system station 16, where it is pretreated, and then further downstream into the printer 28 for printing. Analogous to the change of the assembly level M1, M2, M3 from the printer 28 to the return section 38, the paper web 12 also changes the assembly level M1, M2, M3 from the splicer 60 to the system station 16, and the assembly level M1, M2, M3 is changed again from the system station 16 to the printer 28. The overall length of the corrugator 2 thus remains unchanged.

Alternatively or in addition to the system station 16 above the splicer 60, a system station 16 is arranged along the drying section 32, e.g. along the vertical section 37 and/or along the reverse section 38 and/or above the printer 28. Such a system station 16 is in 1 shown as an example as a drying unit 34, but other configurations for the system station 16 are also possible. The explanations for the system station 16 above the splicer 60 apply accordingly.

In the embodiment of the 6 the return section 38 is length-adjustable, i.e. has an adjustable length. On the one hand, this means that the dwell time is adjustable, and on the other hand, the adjustable length is also advantageous for threading the printed paper web 12a into the return section 38. In the embodiment shown here, the return section 38 has a dancer 64 and is therefore length-adjustable for setting a dwell time for drying the printed paper web 12a. The dancer 64 corresponds in this case to the deflection element 42, but this is not mandatory. The dancer 64 can be moved in and against the longitudinal direction L to adjust the length of the return section 38. In principle, the dancer 64 can also be moved obliquely or perpendicularly to the longitudinal direction L, i.e. up and down (not shown), alternatively or additionally. Analogously, in an embodiment not shown, the vertical section 37 is length-adjustable.

In the 6 In the embodiment shown, the dancer 64 can even be guided up to a front side 66 of the printer 28 for threading the printed paper web 12a into the reverse section 38. The dancer 64 can therefore be moved forward up to a threading position 68, which here is also an end position for the dancer 64, so that in the threading position 66, a minimum length of the reverse section 38 is simultaneously set. The threading position 66 is also located in front of the front side 66 of the printer 28.

List of reference symbols

2

Corrugated board plant

4

back

6

front

8

Wet End

10

Dry End

12

Paper web

12a

printed paper web

12b

Semi-finished product (half-shaft)

14

Unwinding unit

16

Plant station

18

Corrugated board web

20

Single Facer

22

Preheater

24

Glue plant

26

Double Facer

28

Printer

30

printed side

32

Dry section

34

Drying unit

36

print head

37

Vertical section

38

Reverse section

39

first deflection element

40

(second) deflection element

42

(third) deflection element

44

Bonding point

46

Printing point

48

connecting line

50

Forward section

52

Bridge

54

space

56

catwalk

58

Height

60

Splicer

62

Unwinder

64

dancer

66

front

68

Threading position

A

alternative positions for the printer

L

Longitudinal direction

M1, M2, M3

Mounting level

Claims (15)

Corrugated board system (2), a. which extends in a longitudinal direction (L) from a rear side (4) to a front side (6), b. which has a wet end (8) which begins at the rear side (4) and a dry end (10) which ends at the front side (6), c. which is designed to produce corrugated board from a plurality of paper webs (12, 12a), d. which has a printer (28) for printing one of the paper webs (12) so that it then becomes a printed paper web (12a) with a printed side (30), e. which has a drying section (32) for the printed paper web (12a), f. wherein the drying section (32) begins at the printer (28). Corrugated board plant (2) to Claim 1 , wherein the drying section (32) has a return section (38) which leads in the direction of the rear side (4), so that the printed paper web (12a) is guided on the return section (38) counter to the longitudinal direction (L). Corrugated board plant (2) to Claim 1 or 2 , wherein the drying section (32) has a vertical section (37) which leads upwards or downwards with respect to the longitudinal direction (L). Corrugated board plant (2) according to one of the Claims 1 until 3 , wherein the drying section (32) is defined in that it begins at a print head (36) of the printer (28) and ends at a deflection element (42) and that the printed side (30) remains untouched between the print head (36) and the deflection element (38). Corrugated board plant (2) according to one of the Claims 1 until 4 , wherein the rearward section (38) is at least 0.5 m long. Corrugated board plant (2) according to one of the Claims 1 until 5 , comprising a bridge (52) under which the printer (28) is arranged, the rearward section (38) being arranged within the bridge (52) or in a space (54) between the printer (28) and the bridge (52). Corrugated board plant (2) to Claim 6 , wherein the bridge (52) has a catwalk (56) from which the return section (38) is accessible, for threading the printed paper web (12a) into the return section (38). Corrugated board plant (2) according to one of the Claims 1 until 7 , wherein said splicer (60) is arranged behind the printer (28) viewed opposite to the longitudinal direction (L), wherein the rearward section (38) extends beyond the splicer (60). Corrugated board plant (2) according to one of the Claims 1 until 8 , wherein said device comprises a splicer (60) which is arranged behind the printer (28) viewed opposite to the longitudinal direction (L), wherein the splicer (60) splices the paper web (12) which is printed with the printer (28), said printer comprising a system station (16) for treating, examining or handling the paper web (12) upstream of the printer (28). Corrugated board plant (2) according to one of the Claims 1 until 9 , wherein a system station (16) is arranged along the drying section (32) for treating, examining or handling the printed paper web (12a) downstream of the printer (28). Corrugated board plant (2) according to one of the Claims 1 until 10 , wherein the rearward section (38) has a dancer (64) and is thereby adjustable in length for setting a dwell time for drying the printed paper web (12a). Corrugated board plant (2) to Claim 11 , wherein the dancer (64) can be guided up to a front side (66) of the printer (28) for threading the printed paper web (12a) into the rear section (38). Corrugated board plant (2) according to one of the Claims 1 until 12 , wherein the drying section (32) is folded, with several sections (38, 50) on which the printed paper web (12a) is guided alternately in the direction of the back (4) and in the direction of the front (6). Method for operating a corrugated board system (2), a. which extends in a longitudinal direction (L) from a rear side (4) to a front side (6), b. which has a wet end (8) beginning at the rear side (4) and a dry end (10) ending at the front side (6), c. which is designed to produce corrugated board from a plurality of paper webs (12, 12a), d. which has a printer (289) with which one of the paper webs (12) is printed, so that it then becomes a printed paper web (12a) with a printed side (30), e. which has a drying section (32) for the printed paper web (12a), f. wherein the drying section (32) begins at the printer (28). Method for converting an original corrugated board plant to a corrugated board plant (2) according to one of the Claims 1 until 13 , wherein the original corrugated board plant has a bridge (52) below which a printer (28) is or is arranged, wherein the bridge (52) is raised so that an intermediate space (54) between the printer (28) and the bridge (52) is enlarged, wherein a rear section (38) of a drying section (32) is then arranged in the intermediate space (54) for drying a paper web (12a) printed with the printer (28).

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