Method for operating corrugated board installation and corrugated board installation

Abstract

The invention relates to a method for operating a corrugated cardboard installation (2), in which a plurality of webs (8, 8a) in a process section (10) of the corrugated cardboard installation (2) are connected to form a corrugated cardboard web (12), one of the webs (8, 8a) being printed with a printed pattern (38) having a plurality of repeating printed pattern elements (40), wherein a desired end dimension (MS), which must be met downstream of the process section (10), is defined for the printed pattern (38), the printed pattern (38) has an actual end dimension (MI) measured by a measuring unit (42) downstream of the process section (10), an end dimension deviation ([Delta] M) is determined from the actual end dimension (MI) and the desired end dimension (MS), and wherein the corrugated board installation (2) has a control unit (4) which controls the actual end dimension (MI) and the desired end dimension (MS). And a control unit which controls the process section (10) in accordance with the end dimensional deviation ([delta] M) in order to minimize the end dimensional deviation ([delta] M). The invention also relates to a corresponding cardboard installation (2).

Description

Technical Field

[0001] The invention relates to a corrugated paperboard equipment operating method and a corresponding corrugated paperboard equipment. Background Art

[0002] Corrugated cardboard plants are used to produce corrugated cardboard. For this purpose, a plurality of webs, more precisely paper webs, are opened by corresponding unwinders and joined to form a corrugated cardboard web along several process sections of the corrugated cardboard plant. Corrugated cardboard plants usually have a wet end and a subsequent dry end, along which the webs are joined to form a corrugated cardboard web, which is then cut along the dry end. The corrugated cardboard web is cut into a plurality of sub-webs in the longitudinal direction of the conveying direction, for example using an automatic cutting / grooving machine, and additional cutting and grooves are performed. Subsequently, the sub-webs are cut into individual paper sheets using a cross-cutting machine and finally unloaded and stored.

[0003] The sheets should be processed with a printed pattern at regular intervals, which can in principle be printed later onto the cut sheets (post-printing) or printed in advance onto one of the webs (pre-printing). In particular, in the case of pre-printing, the webs and the printed pattern printed thereon may shrink due to the specific processes after processing in the corrugated board machine. Temperature and humidification of the webs within the corrugated board machine can lead to shrinkage in particular. As a result, the printed pattern may no longer meet dimensional accuracy when cut. As a compensation, it is possible to track the cut at the dry end. However, this is disadvantageous because, on the one hand, the switching of the automatic cutting / grooving machine during this period can lead to waste and, on the other hand, this also changes the final dimensions of the paper sheets. It is therefore preferred to compensate for the shrinkage of the printed pattern directly. This is possible in principle, as the printed pattern is already printed enlarged to take into account a certain amount of shrinkage. However, the problem is that there is not much room for maneuver for variable operation of the corrugated board machine. For example, changing the web speed can lead to a change in the web contact time during temperature and humidification, which in turn leads to a change in the amount of shrinkage. Accordingly, the web speed must be kept as constant as possible. Summary of the invention

[0004] Against this background, the object of the present invention is to describe an improved method for operating a corrugated board machine and a correspondingly improved corrugated board machine, in particular to ensure the dimensional accuracy of the printed pattern as much as possible.

[0005] According to the invention, this object is achieved by a method having the features of claim 1 and a corrugated board machine having the features of claim 13. Advantageous embodiments, improvements and variants are the subject matter of the dependent claims. The embodiments relating to the method also apply to the corrugated board machine. If the steps of the method are implicitly or explicitly given below, advantageous embodiments of the corrugated board machine follow from them, namely that it is designed to carry out one or more of these steps. For this purpose, the corrugated board machine has in particular a correspondingly designed control unit.

[0006] An important aspect of the invention is the control of the shrinkage of the printed image, in particular within the corrugated board machine. This is different from the control of the web speed, which can be advantageously and almost arbitrarily varied by the control of the shrinkage described here, while ensuring a particularly high dimensional accuracy of the printed image. Overall, a particularly flexible operation can be achieved while ensuring a particularly high dimensional accuracy of the printed image.

[0007] The method is used for operating a corrugated board machine. The method connects a plurality of webs, in particular paper webs, to form a corrugated board web in a process section of the corrugated board machine. The process section is in particular a component of a wet end of the corrugated board machine or is equivalent thereto. Downstream of the wet end, the corrugated board machine has in particular a dry end, which comprises at least one further process section of the corrugated board machine.

[0008] A printing pattern is printed on (at least) one of the webs, the printing pattern having a plurality of repeating printing pattern elements. This web is also referred to as a printing web. The printing pattern thus forms the entire printed content on the web. Printing can take place inside or outside the corrugated board machine, and in any case pre-printing is performed. The printing pattern elements are repeated, in particular, depending on the number of sheets that are ultimately to be processed. Specific printing pattern elements include, for example, logos, patterns, frames, decorations, marks, markings, positioning marks, control marks, etc. The printing pattern elements are repeated, in particular, at least in the longitudinal direction of the web, i.e. in the conveying direction. Preferably, the printing pattern elements are also repeated in the transverse direction, i.e. perpendicular to the conveying direction, and are suitable for a corresponding number of sub-webs running side by side.

[0009] According to the present invention, without limiting the generality, it is assumed that only one of the webs is printed, and the web is the face paper web or the laminate web of the corrugated board web. However, the present invention is also applicable to the case where multiple webs are printed, and the printed web is not necessarily the face paper web or the laminate web.

[0010] Under the framework of the method according to the invention, a nominal end dimension is specified for the printed pattern, which must be met in the downstream process section. For example, the nominal end dimension is the distance between two (especially identical) printed pattern elements (equivalent to: relative position with respect to each other) or the dimension (for example size, length, width) of a single printed pattern element. The nominal end dimension describes the dimension that the printed pattern should actually have when entering the dry end and, in particular, when cutting, and then, in particular, also on the finished paper sheet. Here, preferably, a certain tolerance, for example + / - 5%, is also accepted for the nominal end dimension. For example, the nominal end dimension is specified by the superior corrugated board machine control system based on known printing data of the printing format, or is input via a user interface. The superior control system and / or the user interface are, in particular, components of the corrugated board machine control unit. Optionally, an offset is also similarly indicated for the nominal end dimension, for example for manual correction. The ideal nominal end dimension is determined, for example, by experiments, for example in a proofing process independent of actual operation, or iteratively determined during operation, or is specified on the basis of experience.

[0011] Downstream of the process section, the printed pattern has an actual end dimension which usually differs from the nominal end dimension. The actual end dimension is measured by a measuring unit of the corrugated board system and is determined from the actual end dimension and the nominal end dimension, in particular the end dimension deviation is calculated. The actual end dimension, i.e. the actual end dimension, depends significantly on the processing conditions within the process section and therefore naturally fluctuates. Accordingly, the difference between the actual end dimension and the nominal end dimension results in a so-called end dimension deviation, which is expressed, for example, as a difference or a proportionality factor. Depending on the actual control mode of the process section, the actual end dimension is greater or smaller than the nominal end dimension.

[0012] According to the invention, the corrugated board machine has a controller, which controls the process section according to the end dimension deviation in order to minimize the end dimension deviation (i.e., minimizes the end dimension deviation by means of the controller). The end dimension deviation is therefore used directly or at least indirectly as a deviation signal for the controller. Accordingly, the actual end dimension and the rated end dimension are used directly or at least indirectly as actual values ​​or rated values ​​for the controller. Next, the controller outputs control parameters for controlling the process section, a specific example of which is shown below. If the process section now causes a change in the displacement or scaling of the printing pattern and its printed pattern elements, which in principle leads to a change in the actual end dimension, it is compensated by the controller. Optionally, the controller intervenes only when the end dimension deviation exceeds / is less than a specific limit value defined by the tolerance described above.

[0013] According to the invention, it is also particularly important that the process section, ie one or more plant components of the corrugated board plant, is controlled by the controller rather than the printing press for the printed web. The control system is therefore arranged downstream of the printing process of the printed web and is preferably not influenced by it.

[0014] In a particularly preferred embodiment, a printing size is determined on the basis of the nominal shrinkage and the nominal end size, and the printing pattern is printed with this printing size, so that the controller (along the process section) adjusts the shrinkage of the printing pattern to the nominal shrinkage. Typically, a true positive shrinkage occurs along the process section, i.e. the nominal end size is smaller than the printing size, so that the format is printed after enlargement, which is also called "enlarged printing size". Without limiting the generality, the present invention will take this as an assumption. However, in principle, a negative shrinkage is also possible, i.e. the nominal end size is larger than the printing size, and the described embodiments also apply accordingly.

[0015] In the case of printing with enlarged printing dimensions, a defined shrinkage is permitted within a certain range. This range is defined by the deviation between the printing dimension and the nominal end dimension and is quantified by a compensation value that describes the difference between the printing dimension and the nominal end dimension. The compensation value is, for example, a factor (scaling ratio of the printing dimension to the nominal end dimension) or a displacement (difference between the printing position and the nominal position of the printed pattern element on the format). In practice, the nominal shrinkage is correspondingly specified by the printing dimension and the nominal end dimension, that is, the shrinkage permitted along the process section so that the printing dimension shrinks to the nominal end dimension. Similarly, in the case of a possible different actual shrinkage, an actual shrinkage that may differ from the nominal shrinkage will be obtained downstream of the process section. In the following, the above-mentioned end dimension deviation for the controller is also a dimension for describing the deviation between the actual shrinkage and the nominal shrinkage, and is therefore also referred to as a "shrinkage deviation". By regulating the end dimension deviation described here, the shrinkage of the printed pattern can then be effectively adjusted to the nominal shrinkage, thereby achieving the regulation of the shrinkage. Here, the nominal shrinkage is defined by the compensation value. The compensation value preferably depends on the paper type and / or the (printing) format weight.

[0016] The method described here requires the determination of a desired end dimension. This is also satisfied if a desired shrinkage or compensation value is specifically specified, since the desired end dimension can then be automatically specified using the desired shrinkage or compensation value by means of the known print dimensions.

[0017] In a suitable embodiment, the actual shrinkage is calculated on the basis of the printed dimension and the actual end dimension, and the nominal shrinkage is similarly calculated on the basis of the printed dimension and the nominal end dimension, if not directly specified. Subsequently, the actual shrinkage is compared with the nominal shrinkage, and on this basis, the end dimension deviation is calculated, for example, expressed as the difference or ratio between the actual shrinkage and the nominal shrinkage, or expressed in a combined manner as the ratio of the difference between the actual shrinkage and the nominal shrinkage to the nominal shrinkage. The end dimension deviation describes a part of the overall shrinkage, which is the difference between the actual shrinkage and the nominal shrinkage, that is, the part that occurs accidentally and should be compensated. Similarly, the actual end dimension and the nominal end dimension can also be measured and compared, and the end dimension deviation can be directly obtained therefrom, for example, according to (actual end dimension-nominal end dimension) / nominal end dimension, and the results obtained are equivalent. It can be seen from the described embodiment that different embodiments exist and are applicable in terms of the selection and processing of the actual end dimension and the nominal end dimension, as well as in terms of the selection and determination of the end dimension deviation.

[0018] According to the invention, without limiting the generality, it is assumed that the corrugated board machine has a plurality of equipment parts as follows: a plurality of unwinders for unwinding one of the webs, one or more single-sided machines for processing corrugations for one of the webs and connecting it to the other web, a preheater and a gluing mechanism for gluing the webs together, and a heating and stretching section (double-sided machine) for compressing and drying the webs glued together, thereby finally obtaining the corrugated board web. The above equipment parts are also collectively referred to as the wet end. However, the invention does not focus on the exact configuration of the wet end, and the wet end can also adopt other designs. According to the invention, the wet end is connected to the dry end for cutting the corrugated board web. According to the invention, without limiting the generality, it is assumed that the dry end has an automatic cutting / grooving machine, a cross-cutting machine and a storage rack located downstream thereof. However, other configurations can also be adopted. According to the invention, without limiting the generality, it is assumed that an automatic cutting / grooving machine is used to cut the corrugated cardboard web into a plurality of sub-webs in the longitudinal direction along the conveying direction, and optionally additional cutting and grooves are performed, and then the sub-webs are cut into individual paper sheets using a cross-cutter and finally stored in a storage rack.

[0019] The corrugated board machine further comprises a control unit in order to carry out the method described here. The controller is in particular a component of the control unit.

[0020] In order to measure the actual end dimension, the measuring unit has a sensor unit, preferably an optical sensor unit, such as a camera. The sensor unit is particularly oriented toward the printed web and captures the continuous printed pattern and subsequently also the individual printed pattern elements. The camera does not need to monitor the entire web in this case. The measuring unit furthermore has an evaluation unit, which is connected to the sensor unit and subsequently determines the actual end dimension using the sensor data of the corresponding sensor unit. In particular, the actual end dimension is measured repeatedly. Due to the repetitive nature of the printed pattern elements, the printed pattern has a periodicity at least in the conveying direction, by means of which the actual end dimension can be measured. As described above, the optical measurement of the actual end dimension is particularly suitable for measurements on corrugated board webs, i.e. after the individual webs have been connected to one another, since accurate width measurements can no longer be performed effortlessly on corrugated board webs.

[0021] Different design solutions are applicable for the actual end size. In a particularly preferred design solution, the actual end size is the distance between two printed pattern elements of the printed pattern (distance measurement or relative position measurement), or the actual end position is the size of a single printed pattern element of the printed pattern (size measurement or absolute position measurement). Accordingly, more generally, the actual end size is determined as a relative size, such as the distance between two different or identical printed pattern elements, or as an absolute size, such as the size of a single printed pattern element. Which of the two design solutions is used depends on the exact order and the printed pattern elements actually present.

[0022] Webs and corrugated board webs usually pass through the corrugated board machine in the conveying direction. Preferably, the actual end dimension is then measured in the transverse direction perpendicular to the conveying direction. Similarly, the nominal end dimension is also specified in the transverse direction. Typically, the shrinkage in the transverse direction is about 3 times greater than in the conveying direction and is therefore easier to measure in the transverse direction. Minimizing the deviation of the end dimension is particularly advantageous in both directions.

[0023] The end dimension deviation is eliminated by means of the control of the controller, and for this purpose, the processing process along the process section is appropriately intervened accordingly. The control system thus adjusts the shrinkage caused by the process along the process section to the set shrinkage. Advantageously, the process is thus particularly flexible and the process section can be controlled accordingly and variably without negatively affecting the dimensional accuracy of the printed pattern.

[0024] The process section usually has at least one control parameter which is set by the controller to minimize the end dimension deviation. The control parameter is associated with a corresponding actuator which is a component of the process section and is controlled by the controller via suitable control parameters. The control parameter is preferably selected from the following control parameters: contact angle of the preheater; heat input in the heating and stretching section; temperature or steam pressure on the heating plate (especially as a component of the heating and stretching section); amount of water sprayed (on at least one of the webs) by a spray bar or steam spray bar of the corrugated board machine; amount of glue applied by the glue application mechanism; web speed of the corrugated board machine, i.e. the conveying speed of one of the webs or the corrugated board web. In particular, in the glue application mechanism, the web usually expands due to the moisture introduced into the web by the glue. Spray bars and steam spray bars also cause expansion accordingly. Conversely, any heating and drying process will cause shrinkage. Accordingly, suitable actuators activated by the controller are usually actuators that bring heat and / or moisture to at least one of the webs, i.e. heating tools, cooling tools, drying and / or humidifying tools. For the control parameters, such actuators are in particular heating rollers of preheaters, heating plates of heating and stretching sections, glue rollers of glue coating units, spray bars or steam spray bars, dryers, such as infrared or hot air dryers. Generally, any plant component that influences the shrinkage of the printed web is an actuator suitable for the control described here.

[0025] The web speed also influences the shrinkage and thus the end-size deviation, because with the change in web speed, the contact time of the printed web with the various equipment components also changes, whereby the temperature control and humidification of the web fluctuate accordingly (at least when these equipment components are not operated in an accurately compensated manner). Therefore, as mentioned above, although the web speed is in principle a suitable control parameter, this will limit the flexibility during the operation of the corrugated board machine and may reduce its output. However, in addition to using the web speed as a control parameter for the control described here, the web speed is usually also changed for other reasons, which then leads to corresponding end-size deviations. According to the present invention, such end-size deviations caused by (temporary) changes in the web speed are now advantageously minimized with the help of a controller. Preferably, the controller controls the process section accordingly, without being affected by the web speed of the corrugated board machine. In particular, it can be understood that the web speed does not belong to the input parameters of the controller. In other words: when running at a variable web speed, the controller ensures the ideal dimensional accuracy of the printed pattern.

[0026] In an advantageous embodiment, the nominal end dimension is also specified as a function of the web speed. In a possible embodiment, a plurality of consecutive speed intervals are defined for the web speed, and a specific nominal end dimension value is associated with each of these speed intervals, for example by means of different nominal shrinkage values. This association is determined, for example, by tests. Subsequently, the corresponding value is used for the nominal end dimension as a function of the web speed actually in operation. This allows for further optimization of the control.

[0027] Optionally, in addition to the (first) controller described here, the corrugated board machine also has one or more additional (second) controllers, such as a warping controller or a gluing controller. In the case of multiple controllers, they usually have overlapping or even identical control parameters, so that the same control parameter is subsequently affected by multiple controllers. For the control implemented by such additional controllers, one of the two examples is the warping control to minimize the warping of the finished paper sheet, and the other is the gluing control to control the glue application in the gluing mechanism. This type of control should ensure the highest possible quality of the corrugated board web and the finished paper sheet, so the specific control parameters used are required to have a certain degree of adjustability. The control described here should avoid adverse interference with such additional control as much as possible, so it is preferably arranged at its lower level. In a suitable design, the controller sets the control parameters of the process section within the adjustment range for this purpose, and at least one limit value (such as the minimum value or the maximum value) of the adjustment range is specified by the warping control or the gluing control of the corrugated board machine. In other words: the warping or gluing control by means of the second controller requires that the control parameter set by the first controller lies within a certain limit value interval in order to ensure a sufficient quality in terms of warping or gluing. The control interval is therefore limited to these limit values. Typically, the control parameter whose control interval is limited is used by both the first controller and the second controller, but this is not mandatory in itself; for the control parameters, except for the (shrinkage) control, only the limit values ​​need to be observed, for example to ensure that the second controller is still sufficient for reverse control with another control parameter.

[0028] The sensor unit (or the entire measuring unit in general) is preferably arranged inside the corrugated board machine at a position downstream of which no significant changes in the printed pattern are expected to occur. This is particularly true downstream of the wet end and at the entrance to the dry end. The heating and stretching section of the corrugated board machine in particular marks the end of the wet end, so that in a suitable design, the sensor unit is arranged downstream of the heating and stretching section. In general, the sensor unit is preferably arranged downstream of the wet end and / or in the dry end.

[0029] In a likewise particularly advantageous embodiment, the sensor unit (or the entire measuring unit) is arranged upstream of the automatic cutting / grooving machine of the corrugated board machine, wherein the measuring unit is additionally used to detect markings in order to control the automatic cutting / grooving machine. The terms "upstream" (previous) and "downstream" (after) are to be understood relative to the conveying direction. The markings are processed in particular by printing and serve as control markings for activating the automatic cutting / grooving machine. Accordingly, the same sensor unit / measuring unit and optionally the same markings can be used for controlling the cross-cutting machine. The markings are, for example, bar markings, bar codes, QR codes, etc. and are usually printed pattern elements of a printed pattern. Advantageously, these markings are also used to measure the actual end dimensions, but this is not mandatory and other printed pattern elements can also be used for this purpose. More importantly, the measuring unit now fulfils at least two functions, namely, on the one hand, measuring the actual end dimensions and, on the other hand, detecting markings in order to control the equipment component of the dry end, here the automatic cutting / grooving machine.

[0030] Printing of the web with the printing pattern can be carried out outside or inside the corrugated board machine, wherein the latter is also referred to as inline printing and is preferred. For inline printing, a printing press is integrated in the corrugated board machine, which prints the printing pattern on one of the webs and then generates the printed web. The printing press is preferably arranged directly downstream of one of the unwinders and prints one of the webs before it is connected to the other webs to form a corrugated board web. However, this is not mandatory. The printing press is not in particular a component of the process section, but is outside it. The printing press itself preferably does not contain a printing pattern control system for setting the printing size, etc. Thus, the control to the rated end size is not carried out by the printing press, but outside it by the controller described here, and the corrugated board machine control system next to the printing press. Optionally, however, at least the printing press is controlled, for example by a control unit, so that in addition to the control, the printing size is also adjusted, in particular the compensation value is changed accordingly according to the requirements (for example, by the rated shrinkage). For example, the corrugated board machine is designed as a learning system, which can gradually adjust the compensation value on the basis of multiple production orders. Alternatively or additionally, a statistical analysis of the measured actual end dimensions (equivalent to: actual shrinkage) is performed and the compensation value is continuously adjusted on this basis. Overall, human intervention in the operation of the device can be minimized and the control can be continuously optimized. Accordingly, the cooperation with the other controllers mentioned above that may exist can also be continuously improved.

[0031] If the printing press has its own dryer for drying the printed image, this should advantageously be used in order to achieve an angularization of the web, making it less shrinkage-resistant overall. Similarly, the same effect can be achieved with the dryer in the corrugated board plant. The dryer should be located as close as possible upstream in the process section or upstream outside the process section.

[0032] A corrugated board machine is designed according to the present invention for executing the method described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the following, embodiments of the present invention are explained in more detail with reference to the accompanying drawings, wherein:

[0034] Figure 1 A corrugated cardboard plant is shown;

[0035] Figure 2 Shows Figure 1 How to operate the corrugated cardboard equipment;

[0036] Figure 3 Shows Figure 1 Control system for corrugated board equipment 2;

[0037] Figure 4 A top view of the printed format is shown;

[0038] Figure 5 The actual end dimensions and the nominal end dimensions are shown compared to each other;

[0039] Figure 6 A method variation is shown;

[0040] Figure 7 Another variation of the method is shown. DETAILED DESCRIPTION

[0041] Figure 1 An embodiment of the corrugated board machine 2 according to the present invention is shown in FIG. Figure 2 An example of a method of operating such a corrugated board machine 2 is shown. Figure 3 An embodiment of a control system is shown, which is part of the method and is implemented by a controller 4. The controller 4 is part of a corrugator control unit 6. The method connects a plurality of webs 8, here paper webs, in a process section 10 of a corrugator 2 to form a corrugated web 12. The process section 10 is part of a wet end 14 of the corrugator 2. Downstream of the wet end 14, the corrugator 2 has a dry end 16.

[0042] The corrugated board equipment 2 shown here by way of example has a plurality of equipment components as follows: a plurality of uncoilers 18 for unwinding one of the webs 8, a plurality of single-sided machines 20 for processing corrugations for one of the webs 8 and connecting it to the other web 8, a preheater 22 and a gluing mechanism 24 for gluing the webs 8 and 8a together, and a heating and stretching section 26 (double-sided machine) for compressing and drying the webs 8 and 8a glued together, thereby finally obtaining the corrugated board web 12. The above-mentioned equipment components form a wet end 14, to which is connected a dry end 16 for cutting the corrugated board web 12. In the design shown here, the dry end 16 has an automatic cutting / grooving machine 28, a cross-cutting machine 30 located downstream thereof, and a storage rack 32 located further downstream. As an example, Figure 4 A corrugated cardboard web 12 is partially shown, wherein the dashed lines indicate the cutting by the automatic cutting / grooving machine 28 and the cross-cutting machine 30. The corrugated cardboard web 12 is cut into a plurality of sub-webs 34 in the longitudinal direction along the conveying direction F by the automatic cutting / grooving machine 28, and additional cutting and grooves are performed, which are not shown here. Subsequently, the sub-webs 34 are cut into individual paper sheets 36 by the cross-cutting machine 30 and finally stored in the storage rack 32.

[0043] A printing pattern 38 is printed on (at least) one of the webs 8, which has a plurality of repeating printing pattern elements 40. This web 8a is also referred to as printing web 8a. Figure 4 The printed web 8a in the figure is a laminated web and thus the uppermost layer of the corrugated board web 12 shown there. The printed pattern 38 forms the entire printed content on the web 8a. The printed pattern elements 40 are repeated according to the number of paper sheets 36 that need to be processed in the end. For example, specific printed pattern elements 40 include logos, patterns, frames, decorations, signs, marks 42, positioning marks, control marks, etc. According to the present invention, the printed pattern elements 40 are not only repeated in the conveying direction F, but also in the transverse direction Q perpendicular to the conveying direction F, and are applicable to a corresponding number of sub-webs 34 running side by side ( Figure 4 In the middle are two sub-frames 34).

[0044] In a first step S1 of the method, a desired end dimension M is defined for the printed pattern 38 which must be met downstream of the process section 10. S For example, the nominal end dimension M S The nominal end dimension M is the distance A1 between two (especially identical) printed pattern elements 40 (equivalent to: relative position to each other) or the dimension A2 (eg size, length, width) of a single printed pattern element 40 . S The dimensions that the printed image 38 will actually have upon entering the dry end 16, and particularly upon cutting, and on the finished paper sheet 36 are illustrated.

[0045] The printed pattern 38 has a dimension downstream of the process section 10 that is usually different from the nominal end dimension M. S The actual end size M I This is in line with Figure 4 The same shows the corrugated cardboard format 12 Figure 5 However, the printed pattern 38 has an actual end dimension M I , the actual end size M I Different from the nominal end dimension M shown by overlapping dotted lines S , which is not shown for clarity Figure 4 All distances A1 and dimensions A2 in. Figure 5 The actual end size M I Smaller than the rated end dimension M S , but the opposite is also possible. In a second step S2, the actual end dimension M is measured by the measuring unit 42. I Next, the actual end dimension M I and rated end dimension M S In a third step S3, the end dimension deviation ΔM is determined. Actual end dimension M I It depends largely on the processing conditions within the process section 10 and therefore naturally fluctuates. I and rated end dimension M S The difference between the actual end size M and the actual end size M is obtained, which is expressed as a difference or a proportionality factor, for example. I Larger or smaller than the rated end dimension M S .

[0046] As shown in the previous embodiment, for the actual end size M I Different design solutions are applicable, for example, the distance A1 between two printed pattern elements 40 of the printed pattern 38 (distance measurement or relative position measurement), or the size A2 of a single printed pattern element 40 of the printed pattern 38 (size measurement or absolute position measurement). According to this, more generally, the actual end size M is determined as a relative size, for example, the distance A1 between two different or identical printed pattern elements 40 I , or as an absolute size, such as the size A2 (size) of a single printed pattern element 40. As to which of the two design solutions is used, it depends on the exact order and the actual printed pattern elements 40.

[0047] The webs 8, 8a and the corrugated board web 12 usually pass through the corrugated board machine 2 in the conveying direction F. According to the invention, the actual end dimension M is measured perpendicularly to the conveying direction F in the transverse direction Q. I, but it can also be measured in other directions. According to the invention, similarly, the nominal end dimension M is also specified in the transverse direction Q. S . Similarly Figure 5 As shown in , typically, the shrinkage S in the transverse direction Q is about 3 times greater than that in the conveying direction F.

[0048] In a fourth step S4, the controller 4 controls the process section 10 according to the end dimension deviation ΔM so as to minimize the end dimension deviation. Thus, the end dimension deviation ΔM is used as a deviation signal of the controller 4, and the actual end dimension M I and rated end dimension M S is used as actual value or nominal value. Figure 3 An embodiment of a control system implemented by the controller 4 is shown. Next, the controller 4 outputs a control parameter U for controlling the process section 10. If the process section 10 causes the printing pattern 38 and its printing pattern elements 40 to undergo a displacement or scaling change (e.g., Figure 5 As shown), it is compensated by the controller 4. Optionally, the controller 4 intervenes only when the end dimension deviation ΔM exceeds / is less than a specific limit value.

[0049] In the embodiment shown here, the printed size M D Printing pattern 38, printing size at rated shrinkage S S and rated end dimension M S Based on the above, the controller 4 efficiently adjusts the shrinkage amount S of the printed pattern 38 to the rated shrinkage amount S S In enlarged print size M D In the case of printing, a defined shrinkage is allowed to occur within a certain range (similar to Figure 5 Combined with the actual end size M I And rated end size M S The range is determined by the printed size M D With nominal end dimension M S The deviation between the dimensions M is defined and printed by stating D With nominal end dimension M S The difference between the two is quantified by the compensation value K. The compensation value K is, for example, a factor or a displacement. D and rated end dimension M S Specified rated shrinkage S S , that is, the shrinkage S allowed along the process section 10, so that the printing size M D Shrink to nominal end dimension M S Similarly, in the case where the actual shrinkage S may be different, a shrinkage S may be obtained downstream of the process section 10 that may be different from the nominal shrinkage S.S The actual shrinkage S I Next, the above-mentioned terminal dimension deviation ΔM used in the controller 4 is also used to describe the actual shrinkage amount S I With rated shrinkage S S The size of the deviation between the two ends is also called the "shrinkage deviation". By adjusting the end size deviation ΔM here, the shrinkage S of the printed pattern 38 can be effectively adjusted to the rated shrinkage S. S Here, the rated shrinkage S is defined by the compensation value K. S .

[0050] As mentioned above, the desired end dimension M should be specified in method step S1. S If the rated shrinkage S is specified S or compensation value K, this is also satisfied, because the target shrinkage or compensation value can then be used to calculate the known printing size M. D Automatic determination of nominal end dimension M S These variations of the method are Figure 6 Shown in.

[0051] In a possible design, in the third step S3, the printing size M D And the actual end size M I The actual shrinkage S is calculated based on I , and similarly in the case of printing size M where not directly specified D And rated end size M S The rated shrinkage S is obtained based on S The corresponding variant of the method is Figure 7 Next, the actual shrinkage S I With rated shrinkage S S Compare and calculate the end size deviation ΔM based on this, for example, expressed as the actual shrinkage S I With rated shrinkage S S The difference or ratio between them, or the combination thereof, can be expressed as the actual shrinkage S I With rated shrinkage S S The difference between the rated shrinkage S S The ratio between (i.e., ΔM = (S I –S S ) / S S The end dimension deviation ΔM describes part of the overall shrinkage S, which is the actual shrinkage S I With rated shrinkage S SThe difference between the actual end dimension ΔM and the nominal end dimension M can also be measured and compared. S , and thus directly obtain the end size deviation ΔM, for example, according to (M I –M S ) / M S , the results obtained are comparable. From the embodiments described and Figure 2 , 6 From 7, it can be concluded that the actual end size M I And rated end size M S With regard to the selection and processing of, as well as with regard to the selection and determination of the end dimension deviation ΔM, different design solutions exist and are applicable.

[0052] To measure the actual end dimension M I The measuring unit 42 has a sensor unit 44, which is an optical sensor unit according to the invention, for example a camera. The sensor unit 44 faces the printing web 8a and detects the continuous printing pattern 38 and, subsequently, also the individual printing pattern elements 40. In this case, the camera does not need to monitor the entire web 8a. The measuring unit 42 also has an analysis unit 46, which is connected to the sensor unit 44 and subsequently determines the actual end dimension M using the sensor data of the corresponding sensor unit 44. I The actual end size M will be measured repeatedly I Since the printed pattern elements 40 are repetitive, the printed pattern 38 has periodicity at least in the conveying direction F, and the actual end dimension M can be measured through this periodicity. I .

[0053] The end dimension deviation ΔM is eliminated by means of the control of the controller 4 , and for this purpose, the processing along the process section 10 is appropriately intervened accordingly. Therefore, the control system calculates the shrinkage S caused by the processing along the process section 10 S Adjust to rated shrinkage S S Typically, the process section 10 has at least one control parameter U S , which is set to minimize the end size deviation ΔM through the controller 4. Control parameter U S The corresponding actuator 48 is associated with the actuator, which is a component of the process section 10 and is controlled by the controller 4 via a suitable control parameter U. For example, the following control parameter U S Select the control parameter U S: contact angle of the preheater 22; heat input of the heating and stretching section 26; temperature or steam pressure on the heating plate 50; amount of water sprayed (on at least one of the webs 8, 8a) by the spray bar or steam spray bar of the corrugated board machine 2; amount of glue applied by the glue application device 24; web speed of the corrugated board machine 2. In particular, in the glue application device 24, the webs 8, 8a usually expand due to the moisture brought into the webs 8, 8a by the glue. The spray bar and steam spray bar also cause expansion accordingly. Conversely, any heating and drying process will cause contraction. Accordingly, the suitable actuator 48 actuated by the controller 4 is usually an actuator 48 that brings heat and / or moisture into at least one of the webs 8, 8a, i.e. a heating tool, a cooling tool, a drying and / or humidifying tool. For the control parameter U, such actuators are the heating roller 52 of the preheater 22, the heating plate 50, the glue roller 54 of the glue coating mechanism 24, the spray bar or steam spray bar, and a dryer, such as an infrared or hot air dryer. Generally, any equipment component that can affect the shrinkage amount S of the printing format 8a is an actuator 48 suitable for the control described here.

[0054] The web speed also influences the shrinkage S and thus the end dimension deviation ΔM, because the contact time of the printing web 8a with the various system components also changes with the web speed, which results in corresponding fluctuations in the temperature and humidity of the web 8a. S In addition to the web speed, the web speed is usually changed for other reasons as well, which leads to corresponding end-size deviations ΔM. According to the invention, such end-size deviations ΔM caused by (temporary) changes in the web speed are minimized by means of the controller 4. According to the invention, the controller 4 controls the process section 10 accordingly, independently of the web speed of the corrugated board machine 2. It is understood that the web speed is not an input parameter of the controller 4. In other words: when operating at a variable web speed, the controller ensures the ideal dimensional accuracy of the printed pattern 38.

[0055] In one embodiment, the desired end dimension M can also be specified in a first step S1 as a function of the web speed. S In one possible design, a plurality of consecutive speed intervals are defined for the web speed, and a specific nominal end dimension M is associated with each of these speed intervals. S Values, for example with different nominal shrinkage values ​​S S Next, according to the actual running web speed, the rated end size M S Use the corresponding value.

[0056] In addition to the (first) controller 4 described here, the corrugated board machine 2 shown here by way of example also has one or more additional (second) controllers 56, such as a warping controller or a gluing controller. In the case of multiple controllers 4, 56, they usually have overlapping or even identical control parameters U S , so that the next same control parameter U S Affected by multiple controllers 4, 56. For the control implemented by such additional controller 56, two examples are one of the warping control to minimize the warping of the finished paper sheet 36, and the other is the gluing control to control the glue application in the gluing mechanism 24. This type of control should ensure the highest possible quality of the corrugated board web 12 and the finished paper sheet 36, so the specific control parameters U used are S The control performed by the first controller 4 described here should avoid adverse interference with the additional control performed by another controller 56 as much as possible, so it is arranged downstream. In a possible design scheme, the controller 4 sets the control parameter U of the process section 10 within the adjustment range. S , and at least one limit value (e.g., minimum value or maximum value) of the adjustment interval is specified by the warping control or gluing control of the corrugated board machine 2. In other words, the warping or gluing control performed by the second controller 56 requires the control parameter U set by the first controller 4 S lies within certain limit values ​​in order to ensure adequate quality with regard to warping or gluing. The adjustment range is therefore limited to these limit values. Typically, the control parameter U whose adjustment range is limited S It is used by both the first controller 4 and the second controller 56, but this is not mandatory; S In addition to the control with the first control device 4 , only limit values ​​need to be observed, for example in order to ensure that the second control device 56 is still sufficient for reverse control with another control variable.

[0057] exist Figure 1 In the embodiment of the present invention, the sensor unit 44 (or even the entire measuring unit 42) is arranged inside the corrugated board machine 2 at a location downstream of which no significant changes of the printed pattern 38 are expected to occur. This is the case downstream of the wet end 14 and at the entrance to the dry end 16. The heating and stretching section 26 marks the end of the wet end 14, so that the sensor unit 44 is arranged downstream of the heating and stretching section 26. Typically, the sensor unit 44 is arranged downstream of the wet end 14 and / or in the dry end 16.

[0058] In the embodiment shown here, the sensor unit 44 is also arranged upstream of the automatic cutting / grooving machine 28 and is additionally used to detect the markings 40 in order to control the automatic cutting / grooving machine 28. According to the invention, these markings 40 are also used to measure the actual end dimension M. I , but this is not mandatory and other printed pattern elements 40 can also be used for this purpose. The mark is processed by printing and serves as a control mark for activating the automatic cutting / grooving machine 28. Optionally, the same sensor unit 44 / measuring unit 42 and further optionally the same mark 40 are used for controlling the cross-cutting machine 30. According to the invention, the mark 40 is a bar mark and is usually a printed pattern element 40 of the printed pattern 38. Now, the measuring unit 42 fulfils at least two functions, namely on the one hand measuring the actual end dimension M I On the other hand, the mark 40 is identified to control the equipment component of the dry end 16, here the automatic cutting / grooving machine 28.

[0059] The printing of the web 8 with the printed pattern 38 can be carried out outside or inside the corrugated board machine 2, wherein the latter is Figure 1 In the embodiment shown in FIG. 1 and referred to as inline printing. For inline printing, a printing press 58 is integrated in the corrugated board machine 2, which prints a printed pattern 38 on one of the webs 8, thereby generating a printed web 8a. According to the invention, the printing press 58 is arranged directly downstream of one of the unwinders 18 and prints one of the webs 8 before it is connected to the other webs 8 to form the corrugated board web 12. However, this is not mandatory. The printing press 58 is not a component of the process section 10, but is external to it. The printing press 58 itself also does not contain a device for setting the printing size M. D Thus, to the rated end size M S The regulation of the printing size M is not performed by the printing press 58, but outside of it by the controller 4 described here, and the control system of the corrugated board machine 2 next to the printing press 58. However, optionally, at least the printing press 58 is controlled, for example by the control unit 6, so that in addition to the above regulation, the printing size M is also controlled. D Make adjustments, such as changing the compensation value K accordingly as required.

[0060] If the printing press 58 has its own dryer for drying the printed image 38, this dryer can also be used to achieve an angularization of the web 8a, making it less shrinkage-resistant overall. Similarly, the same effect can be achieved using a dryer in the corrugated board plant 2. Such a dryer should be located as close as possible upstream in the process section 10 or upstream outside the process section.

[0061] Reference numerals list

[0062] 2Corrugated cardboard equipment

[0063] 4 (First) Controller

[0064] 6Control Unit

[0065] 8 Frames

[0066] 8a printing format

[0067] 10 process section

[0068] 12 corrugated cardboard format

[0069] 14 wet end

[0070] 16 Dry end

[0071] 18 Uncoiler

[0072] 20 Single-sided machine

[0073] 22 Preheating machine

[0074] 24 Gluing mechanism

[0075] 26 Heating and stretching section

[0076] 28 Automatic cutting / grooving machine

[0077] 30 Crosscutting Machine

[0078] 32 Storage racks

[0079] 34 sub-format

[0080] 36 pieces of paper

[0081] 38 Printing Patterns

[0082] 40 Printing pattern elements and logos

[0083] 42 measuring units

[0084] 44 sensor units

[0085] 46 Analysis Units

[0086] 48 actuators

[0087] 50 Heating Plate

[0088] 52 Heating roller

[0089] 54 Glue coating roller

[0090] 56 (Second) Controller

[0091] 58 Printing press

[0092] A1 Distance

[0093] A2 size

[0094] FConveying direction

[0095] K compensation value

[0096] M D Printing size

[0097] M I Actual end size

[0098] M S Rated end size

[0099] QHorizontal

[0100] S shrinkage

[0101] S I Actual shrinkage

[0102] S S Rated shrinkage

[0103] S1 First step

[0104] S2 Second step

[0105] S3 Step 3

[0106] S4 Step 4

[0107] U control parameters

[0108] U S Control parameters.

Claims

1. A method for operating a corrugated board machine (2), a. wherein a plurality of webs (8, 8a) within the process section (10) of the corrugated board equipment (2) are connected to form a corrugated board web (12); b. Among them, One of the webs (8, 8a) is printed with a printed pattern (38), wherein the printed pattern (38) has a plurality of repeated printed pattern elements (40); c. wherein the printed pattern (38) specifies a nominal end dimension (M) that must be met downstream of the process section (10) S ); d. wherein the printed pattern (38) has an actual end dimension (M) measured by a measuring unit (42) downstream of the process section (10) I ); e. Wherein, the actual end size (M I ) and the rated end size (M S ) determine the end size deviation (ΔM); f. The corrugated board machine (2) has a controller (4), which controls the process section (10) according to the terminal dimension deviation (ΔM) so as to minimize the terminal dimension deviation (ΔM).

2. The method according to claim 1, in, Print size (M D ) prints the printed pattern (38), the printed size is within the rated shrinkage amount (S S ) and the rated end size (M S ), so that the controller (4) adjusts the shrinkage amount (S) of the printed pattern (38) to the rated shrinkage amount (S S ).

3. The method according to claim 1 or 2, in, The actual end size (M I ) is the distance (A1) between two of the printing pattern elements (40) of the printing pattern (38).

4. The method according to claim 1 or 2, in, The actual end size (M I ) is the size (A2) of a single printed pattern element (40) of the printed pattern (38).

5. The method according to any one of claims 1 to 4, in, The webs (8, 8a) and the corrugated board web (12) pass through the corrugated board machine (2) along a conveying direction (F), The actual end dimension (M) is measured in the transverse direction (Q) perpendicular to the conveying direction (F). I ).

6. The method according to any one of claims 1 to 5, in, The process section (10) has at least one control parameter (U S ), the at least one control parameter is set to minimize the end size deviation (ΔM) through the controller (4), and is selected from the following control parameters (U S ): a. The contact angle of the preheater (22) of the corrugated board equipment (2); b. the heat input into the heating and stretching section (26) of the corrugated board equipment (2); c. the temperature of the heating plate (50) of the corrugated board equipment (2); d. the steam pressure of the heating plate (50) of the corrugated board equipment (2); e. the amount of water sprayed by the spray bar or steam spray bar of the corrugated board equipment (2); f. The amount of glue applied by the gluing mechanism (24) of the corrugated board equipment (2); g. The web speed of the corrugated board equipment (2).

7. The method according to any one of claims 1 to 6, in, The controller (4) controls the process section (10) accordingly, without being affected by the web speed of the corrugated board machine (2).

8. The method according to any one of claims 1 to 7, in, The rated end size (M) is determined according to the web speed of the corrugated board equipment (2). S ).

9. The method according to any one of claims 1 to 8, in, The controller (4) sets the control parameters (U S ), At least one limit value of the adjustment interval is specified by warping control or gluing control of the corrugated board machine (2).

10. The method according to any one of claims 1 to 9, in, The corrugated board equipment (2) has a heating and stretching section (26), Therein, the measuring unit (42) has a sensor unit (44) arranged downstream of the heating and stretching section (26).

11. The method according to any one of claims 1 to 10, in, The corrugated board machine (2) has an automatic cutting / grooving machine (28), wherein the measuring unit (42) has a sensor unit (44) arranged upstream of the automatic cutting / grooving machine (28) and is additionally used to recognize a mark (40) in order to control the automatic cutting / grooving machine (28).

12. The method according to any one of claims 1 to 11, in, A printing press (58) is integrated into the corrugated board machine (2), wherein the printing press (58) prints the printed pattern (38) on one of the webs (8).

13. A corrugated board machine (2) designed to carry out the method according to any one of claims 1 to 12.

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