DESCRIPTION

Field of the invention

The present invention relates to the paper converting machines for producing products of di f ferent types such as logs of toilet paper, logs of kitchen paper, but also packages of napkins , tissue papers , towels , etc . starting from at least one reel of paper , and in particular it relates to a system for setting the aforementioned paper converting machine .

The invention, furthermore , relates to a method for setting the aforementioned paper converting machine .

Description of the prior art

As it is known, in the paper industry for producing logs or packages of sheets o f paper, for example absorbing paper for toilet paper, or kitchen paper, in particular drying paper, machines exist that work starting from big reels of paper . These are obtained by production plants which gradually reduce the amount of water of a mixture of cellulosic fibres , water, in addition to a series of additives of di f ferent types , through a sequence of passages up to reach a consistency such that allows the veil of wet paper to pass through a drying section . This , normally, comprises at least one dryer cylinder, also known as Yankee cylinder, that is made of steel or cast iron and a hood which is fed with hot air . In particular, the worked veil of wet paper is laid on the external surface of the dryer cylinder, whilst the inside of the Yankee cylinder same i s heated for example by inj ecting steam . Because of the heat produced within the Yankee cylinder and the hot air which is blown by the hood on the paper, the veil of wet paper laid on the external surface is gradually dried . When the desired drying value is reached, the veil of paper is removed from the external surface of the Yankee cylinder by a blade , or a doctor blade , or by tensioning, depending on the desired product and in particular crepe paper, or smooth paper .

The veil of dried paper that i s so obtained is , then, subj ected to a series of intermediate operations and, then, is sent to a winding station for producing the reel of paper of big si ze . In particular, the production plant provides also to carry out the packaging of the reel o f paper by applying a film, or layer, normally made of a transparent material , and the labelling of the same . More precisely, on the label are present some data or parameters which relate to the reel of paper, among which the diameter, the height , and the weight , but also data and parameters which relate to the type of paper of the reel , for example the paper weight , the number of veils , the maximum percentage elongation that can be tolerated, but also the number and the position of any defect detected during the production of the reel of paper . For example , it is possible that during the winding of a reel o f big diameter, or mother reel , a breaking of the veil occurs ( or of the veils in case of reel formed by more veils ) which requires to carry out a j oining before starting again and finishing the winding of the reel same up to the final diameter . Furthermore , it is possible that the veil or the veils wound to form the reel of big diameter have tears , or in general defects , due to the fact that the working conditions are not exactly the same during the production process of the veil same .

All these data are , in fact , indispensable because the plant to which the reel of paper is sent to be subj ected to a series of operations in order to be converted into the final product , works correctly and at the maximum production capacity, without compromising its functioning .

The aforementioned data are normally consulted for controlling the quality of the reel and, therefore , to veri fy that the paper of the reel is appropriate for the type of product into which the same has to be converted .

However, these data are not directly used for setting the best working configuration for the aforementioned paper converting machines . Only in some cases it is possible to carry out some operations manually using some information which relate to the defects of the reel that is mounted on the machine . For example , a worker can read from the label or from a mark provided at one side o f the reel that at a determined diameter of the mother reel same there is a hole , or a j oining of the veils , and, therefore , at that predetermined diameter he/ she reduces considerably the speed of production to avoid the breaking of the veils and to discharge the final paper product which contains the veils with the defects . Normally, the worker does not optimally set the converting machine , but reduces the speed of production in order to avoid a stop of production .

These procedures carried out manually by the worker, are subj ect to errors or oversights which cause the paper converting machine to be stopped for a long time , thus producing economic losses . In addition to the above , a machine which is not correctly set , that means set in a way that does not correspond to the characteristics of the starting reel of paper, can lead to use in a non-optimi zed way the paper converting machine and, therefore , to have a productivity that is less than the one that could be reached, but also to obtain a product of low quality, up to the damage of the worked paper, which can be broken and j am the di f ferent parts of the machine , with consequent loss of productivity and time in order to carry out the necessary extraordinary maintenance interventions to remove the j ammed paper and start again the process .

An example of a prior art solution with the aforementioned drawbacks is described in WO2015/ 160915 . In this case a system for producing products made of paper i s provided comprising a machine for forming a web of paper provided with a plurality of sections . The machine analyzes the web of paper in order to identi fy the proprieties and to mark the web of paper same with a series of marks , each of which assigned to a section of the aforementioned plurality . The instrument of analysis assigns a speed to the paper at each section on the basis of the properties o f the web of paper identified in that section . However, the solution described in WO2015/ 160915 in order to detect the data have to unwind the reel o f paper . Therefore , i f the machine is set on the basis of a web of paper having di f ferent properties with respect to the one mounted, a lot of drawbacks can occur, such as paper j am along the line , or tears , or wrinkles , which are not desired on the product with consequence loss of product and productivity for the need of unwinding, extraordinary maintenance interventions are necessary to remove the paper j ammed or damaged before starting again the machine .

Other examples of the prior art with analogous drawbacks are described in DE102009029081 , DE102009029082 , DE102009029083 , DEI 02009029084 , US4463251 and EP0875482 .

Summary of the invention

It is , therefore , an obj ect of the present invention to provide a system for setting a paper converting machine starting from a reel of paper, in particular for producing logs of toilet paper, or logs of kitchen paper, but al so packages of product , such as packages of napkins , tissue papers , towels and similar products , in particular folded or interfolded, that is able to overcome the aforementioned drawbacks of the prior art solutions .

It is also an obj ect of the present invention to provide a method for setting a paper converting machine starting from a reel of paper having analogous advantages .

These and other obj ects are achieved by a system for setting a paper converting machine for producing products made of paper starting from a reel of paper associated to a label on which a plurality of data or parameters related to the same are present , each datum or parameter being graphically represented by at least one alphabetic character or numeric character, said machine comprising : an unwinding group configured to unwind said reel of paper obtaining a web of paper ; a displacement group configured to cause the aforementioned web of paper to advance through said paper converting machine at a determined advancement speed along a predetermined advancement path; a control unit configured to operate said displacement group in such a way to adj ust the advancement speed of said web of paper along said predetermined advancement path; whose main characteristic is that it , furthermore , comprises an optical detection device configured to recogni ze and acquire said or each graphic element, which is present on said label of said reel of paper .

Other technical characteristics of the invention and related embodiments are defined by the dependent claims .

In particular, the optical detection device can be arranged to recognize and acquire the or each graphic element which is present on the label before actuating the unwinding group for unwinding the reel .

Preferably, each datum or parameter of the reel can be graphically represented by a plurality of alphabetic characters . More in detail , each parameter o f the reel can be associated to a respective numeric value which, advantageously, defines the value of the parameter same . In particular, the numeric value can comprise at least one numeric character .

Alternatively, the aforementioned graphic element can be a barcode , or a QR code , or an analogous code .

In particular, the aforementioned optical detection device can be , furthermore, configured to send the or each graphic element to the control unit . More in particular, the aforementioned control unit can be configured to set the machine , for example the displacement group, on the basis of the or each graphic element recognized by the optical detection device .

In addition, or alternatively, the aforementioned optical detection device can be configured to send the or each, detected graphic element to a display device .

Advantageously, the optical detection device can comprise a digital video camera provided with a software for the optical character recognition, or "OCR" .

In particular, on the aforementioned label can be indicated at least one datum or parameter selected from the group comprising : paper weight ; diameter of the reel ; number and position of the defects ; number of veils ; elongation percentage ; diameter of the core of the reel ; height of the reel ; air permeability of paper; residual moisture .

Advantageously, on the label can be indicated at least the number and the position of the or each defect , and wherein the control unit can be arranged to operate the displacement group in such a way to reduce or bring to zero the advancement speed when the positions of the or each defect of the web or sheet of paper reaches the predetermined positions of said advancement path .

In some cases , for position of defect is intended the diameter, or radius , of the reel corresponding to the point where the defect is present in the veil of paper . Alternatively, it is possible to indicate the position of the defect with a distance measured starting from the core of the mother reel .

In particular, the control unit can be configured to operate a discharge device to rej ect at least one product obtained starting from the reel of paper and containing the or each defect of the web of paper .

In a possible embodiment of the invention, the paper converting machine can comprise a tension measurement group configured to measure the tension applied to the web of paper during its movement along the predetermined advancement path . In particular, the tension measurement group can be arranged to generate and send to the control unit data relating to the tension applied to the web of paper . More in particular, the control unit can be configured to operate the unwinding group and/or the displacement group in such a way that said tension measured by the measurement group is kept within a predetermined range of tension values computed on the basis of a value of elongation percentage detected by the optical detection device on the label .

In an alternative embodiment provided, the control unit can be configured to keep the tension of the paper to the desired tension using the value of the elongation percentage to adj ust and operate opportunely the displacement group and/or the unwinding group .

In an alternative embodiment of the invention, the paper converting machine can comprise a folding or interfolding group configured to fold or interfold a sheet or web of paper according to a predetermined folding or interfolding configuration . Advantageously, the folding or interfolding group can be operatively connected to a device for generating a determined vacuum degree .

In particular, on the label can be indicated at least the value of the permeability of the paper that is detected by the optical detection device . More in particular, the control unit can be configured to operate the device for generating the determined vacuum degree in such a way to set a determined vacuum degree computed on the basis of the aforementioned permeability of paper value .

Advantageously, the control unit can be configured to store in a database the or each alphabetic and/or numeric character of the or each parameter recogni zed and acquired by the optical detection device .

In particular, a positioning group can be , furthermore, configured to position the optical detection device and the reel of paper in a predetermined relative position one with respect to the other, in such a way to detect at least one graphic element associated to the or each datum or parameter arranged in a predetermined position .

According to another aspect of the invention, a method for setting a paper converting machine for producing products made of paper starting from a reel of paper associated to a label on which a plurality of data or parameters are present that relates to the same , each datum or parameter being graphically represented by at least one graphic element , said method comprising the steps of : unwinding said reel of paper obtaining a web of paper ; moving said web of paper along said paper converting machine at a determined advancement speed along a predetermined advancement path, said moving step being carried out actuating a displacement group by a control unit ; whose main characteristic is that it, furthermore , provides the steps of : detecting said or each graphic element associated to at least one datum or parameter of said plurality of parameters which are present on said label of said reel of paper by an optical detection device ; acquiring said or each recognized graphic element of said or each datum or parameter of said plurality of data or parameters which are present on said label of said reel of paper by said optical detection device . Preferably, the recognition step can be carried out before starting the unwinding of the reel of paper by the unwinding group .

In particular, the aforementioned recognition step of the or each alphabetic and/or numeric character can be carried out before positioning the reel of paper on the unwinding group .

Alternatively, the aforementioned recognition step can be carried out after having positioned the reel of paper on the unwinding group .

Brief description of the drawings

The invention will now be shown with the following description of its exemplary embodiments , exempl i fying but not limitative , with reference to the attached drawings in which :

- Fig . l diagrammatically shows a plan view of a first embodiment of a system, according to the invention, to set a paper converting machine starting from a reel of paper ;

- Fig . 2 diagrammatically shows a side elevation perspective view of a reel provided with a label to which the system, according to the invention, for setting a paper converting machine can be applied;

- Fig . 3 diagrammatically shows an enlargement of the label of figure 2 to highlight some features of the s ame ;

- Fig . 4 diagrammatically shows a further enlargement o f the label of figure 3 to show some features of the present invention;

- the figures from 5 to 16 diagrammatically show side elevation perspective views of some possible alternative embodiments of the system, according to the invention, or parts of the same , for setting a paper converting machine .

Detailed description of some exemplary embodiments of the invention

In figure 1 , a system 200 is diagrammatically shown, according to the invention, for setting a paper converting machine 1 for producing products such as logs of toilet paper, logs of kitchen paper, but also packages of napkins , tissue papers , towels , etc . starting from a reel of paper 10 . This , as known, is associated to a label 15 on which a plurality of data or parameters 16 related to the reel 10 of paper is present , for example reproduced by printing or carving or applying elements in relief .

In particular, as shown in detail in the figures from 2 to 4 , each datum or parameter 16 is graphically represented by at least one graphic element . This can be, for example , an alphabetic character 17 and/or at least a numeric character 19 , but also a barcode or a QR code or similar codes , cases that are not shown in figure for simplicity . For example, as diagrammatically indicated in figure 4 , each datum or parameter 16 , in the example the parameter 16f "core" intended as the external diameter of the tubular body about which the paper of the reel 10 is wound, can be graphically represented by a plurality of alphabetic characters 17a, ..., 17n, in the case of figures 4 , 5 alphabetic characters 17a- 17e . In particular, each datum or parameter 16 can be , furthermore , associated to a respective numeric value 18 , in the case of figure 4 comprising two numeric characters 19a and 19b .

In particular, on label 15 at least one datum or parameter 16 can be present that is selected from paper weight , i . e . the weight in grams of a sheet of 1 m ² , the diameter of the reel , the number and the position of the defects , the number of veils , the elongation percentage , i . e . the maximum elongation expressed in % that can be tolerated by the paper, the diameter of the core of the reel 10 , the height of the reel 10 , residual moisture of the or each veil of paper, the air permeability of each single veil of paper, and the height of the reel . More in particular, each parameter can be graphically represented by a series of alphabetic characters and to each parameter can be associated a respective numeric character which, advantageously, defines its value . In general , the machine 1 comprises an unwinding group 20 , described in detail below, configured to unwind the reel of paper 10 obtaining a web of paper 100 . A displacement group 30 is , furthermore , provided comprising, for example , a series of rolls 35 some of which operated in particular by motors , some others , instead, idle , which together define a predetermined advancement path for the web of paper 100 along the machine 1 . In particular, the displacement group 30 is configured to cause the web of paper 100 to advance at a determined advancement speed along a predetermined advancement path 101 through the dif ferent sections of the paper converting machine 1 . This can, furthermore , comprise a control unit 300 configured to operate the displacement group 30 in such a way to adj ust the advancement speed of the web of paper 100 through the di f ferent sections of machine 1 , in particular according to the aforementioned data or parameters 16 indicated on the label 15 . According to the present invention, an optical detection device 50 is , furthermore , provided configured to detect and acquire the or each graphic element indicated on the label , such as one or more alphabetic characters 17 and/or one or more numeric characters 19 of at least one datum or parameter 16 of the aforementioned plurality of data or parameters indicated on the label 15 associated to the reel of paper 10 . In particular, the optical detection device 50 can be arranged to detect and acquire the or each graphic element which is present on the label 15 before actuating the unwinding group 20 for unwinding the reel 10 .

The aforementioned optical detection device 50 can comprise a device for acquiring images , for example a digital video camera, advantageously associated to a software for the optical character recognition or OCR . More in detail , the device for acquiring images can be configured to acquire images from the label 15 and to send corresponding data to a microcontroller configured to process the acquired images with a software of OCR type and to convert the data into at least one alphanumeric character . In an embodiment provided, the image acquisition device can be provided with the aforementioned software for optical character recognition or OCR .

Advantageously, the optical detection device 50 can move with respect to the reel 10 in such a way to be able to position at the label 15 . For example , as diagrammatically shown in the figures 15 and 16, the optical detection device

50 can be mounted on a support frame 55 in such a way to be able to move with respect to the same . In particular, the support frame 55 can be configured to guide the optical acquisition device 50 along at least one sliding direction 56 with respect to the reel 10 , for example parallel to the longitudinal axis 110 of the reel 10 ( figure 15 ) .

In particular, the optical detection device 50 can be configured to be able to automatically detect the position of the label 15 once positioned at the same . Alternatively, the optical detection device 50 can be associated to a detection member, not shown in the figures for simplicity, arranged to identi fy the position of the label 15 and to transmit the position of the same to a processing unit which, then, causes the optical acquisition device 50 to move accordingly, in order to position the same at the aforementioned position .

In an embodiment provided, the optical acquisition device 50 and the reel 10 can be adapted to rotate one with respect to the other . In particular, as diagrammatically shown in figure 16 , the support frame 55 can be provided with a curvilinear guide portion 57 along which the optical acquisition device 50 can slide . More in particular, in this case , can be the curvilinear guide portion 57 to be slidingly mounted along at least the sliding direction 56.

In an embodiment not shown in the figure , the reel 10 can be mounted on a rotating platform, in such a way to rotate with respect to the optical acquisition device 50 .

Advantageously, the optical detection device 50 can move with respect to the reel 10 in such a way to be able to position at the label 15 . For example , the optical detection device 50 can be mounted on a support frame 55 in order to be able to move with respect to the same . In particular, the support frame 55 can be configured to guide the optical acquisition device 50 along at least a sliding direction with respect to the reel 10 .

In particular, the recognition of the or each graphic element , for example one or more alphabetic characters 17 and/or one or more numeric characters 19 , can be carried out by the optical detection device 50 before positioning the reel of paper 10 on the unwinding group 20 , for example at a store area . Alternatively, the recognition can be carried out before or after having positioned the reel of paper 10 at the unwinding group 20 of the machine 1 .

As diagrammatically shown, for example, in figure 1 , the aforementioned optical detection device 50 can be , furthermore , configured to send the or each, alphabetic character 17 and/or numeric character 19 of the recognized datum or parameter to the control unit 300 . Alternatively, or in addition, the aforementioned optical detection device 50 can be adapted to send the acquired graphic elements , such as alphabetic characters 17 and/or numeric characters 19 , to a display device . In this case , a worker can be provided for veri fying that the optical detection device 50 has correctly "read" and acquired the characters indicated on the label 15 . In particular, the worker can, in case, correct any reading errors and confirm the read data or parameters before sending the same to the control unit 300 .

In particular, a support group 70 comprising a first and a second support member 71 and 72 can be provided positioned at opposite sides with respect to the reel 10 . More in particular, the first and second support members 71 and 72 can be provided with respective engagement portions 73 and

74 adapted to engage the reel 10 to a tubular core 12 of which the same is provided with ( figure 8 ) , in such a way that the reel 10 is free to rotate about its longitudinal axis 110 . By the unwinding of the reel 10 carried out by the unwinding group 20 , a web of paper 100 is obtained that is worked through the di f ferent sections of the machine 1 . In particular, the first and second support members 71 and 72 can be slidingly mounted on a guide 78 ( along respective direction parallel to the axial direction of the reel 10 to move from a respective position external to the tubular core 12 ( condition indicated in figure 8 with a broken line ) to a respective position internal to the same ( condition indicated in figure 8 with an unbroken line ) .

As diagrammatically shown in figure 9, the unwinding group 20 can provide at least one unwinding member 22 , advantageously a flexible unwinding member, for example a belt 22 , preferably a plurality of unwinding members 22 parallel to each other . More in particular, the or each, unwinding member 22 is mounted on a series of deflection members , for example 5 deflection rolls 21a-21e , at least one of which, in the case of figure 9 the deflection member 21d, operatively connected to a motor 25 , for example by a transmission belt 23 , in such a way to cause the same to rotate about a respective rotation axis . The or each, unwinding member 22 is positioned in contact with the reel 10 and is , advantageously, provided with a surface having a high friction in such a way to transmit to the reel 10 same the motion and to cause the same to be unwound .

A push member 75 is , advantageously, furthermore , provided configured to keep the periphery of the reel 10 in contact with the or each unwinding member 22 during the unwinding of the same in such a way to assure that during the unwinding of the reel 10 , the or each unwinding member is able to exert the unwinding action on the same, in particular for the presence of the high friction surface of which it is provided with . In particular, the push device 75 can comprise a first actuator 75a associated to the first support member 71 and a second actuator 75b associated to the second support member 72 . More precisely, the first and second actuators 75a and 75b are adapted to exert a push action, respectively, on the first and the second support member 71 and 72 , in such a way that these rotate about a respective fulcrum 76 and 77 to push in a controlled way the reel 10 against the or each unwinding member 22 . More in detail , the unwinding of the reel 10 is caused by the or each unwinding member 22 operated by the motor 25. In this way, the web of paper 100 is fed along an advancement path 101 . During the unwinding of the reel 10 , the diameter of the same gradually decreases , but the unwinding action is , however, assured by the action of the first and second actuators 75a and 75b which cause the reel 10 to lower towards the or each unwinding member 22 thus causing a rotation of the first and second support members 71 and 72 about the fulcra 76 and 77 as described above . Furthermore , a device can be provided for tensioning the or each unwinding member 22 , not shown in the figure 9 for reasons of clarity, adapted to contribute to compensate the aforementioned reduction of the diameter of the reel 10 .

For the aims of the invention, also other types of unwinders of prior art can be used . In particular, an unwinder can be provided which progressively draws each unwinding member 22 near to the reel 10 as the diameter decreases . Alternatively, it is possible to have an unwinder 20 which actuates the reel by putting in rotation the core 110 of the reel 10 directly by a motor . In this case the j argon expression central unwinders is used, whilst in the previous cases , the j argon expression peripheral unwinders is used . It is possible also to use central-peripheral unwinders without changing the aims of the invention .

In particular, the paper converting machine 1 can comprise at least one tension measurement group 40 configured to measure the tension to which the web of paper 100 moved along the aforementioned predetermined advancement path 101 is subj ected to , and to send corresponding data to the control unit 300 . More in particular, the control unit 300 , in this case , can be configured to operate the unwinding group 20 and/or the displacement group 30 in such a way that the value of the tension measured by the tension measurement group 40 is kept within a predetermined range of values . More precisely, the aforementioned predetermined range of values of the tension can be computed on the basis of the value of the elongation percentage that is read as parameter indicated on the label 15 by the optical detection device 50 . The tension to which the web of paper 100 is subj ected, is a very important operative parameter for the correct functioning of the machine 1 and for obtaining a high quality product and its value have to be kept within a determined range for the reasons indicated below . A too low tension, in particular less than a lower threshold value , can cause the paper to deviate from the correct line, to form wrinkles and to incorrectly work the same in particular at determined sections , such as for example at the printing or the embossing sections . On the other side, i f the paper tension is too high, in particular higher than an upper threshold value, the paper can be broken or torn . In this case, it is necessary to move the web of paper 100 again through the line , at least downstream of the breaking point . This unavoidably implies to stop the machine and to have long stop times during production . The elongation percentage datum is also important at the cutting station in order to divide the web 100 into a series of sheets of predetermined length . I f the paper has a high elongation percentage value and is subj ected to a high tension, it is likely that the cut-of f , i . e . the length of each single sheet , can be reduced after the cut and, therefore , that, at the suction rolls , i f present , some suction holes can be covered causing paper am due to the fact that the sheets are no more kept by the suction holes on the external surface of the roll same . In practice, if a veil of paper that is very long because of the tension, is cut, it is very likely that after the cut , the paper can go back to a tension equal to zero , thus shortening . The cut-of f is , therefore , shorter causing the above disclosed problems .

In the example diagrammatically shown in figure 9 , a group 40 for measuring the tension is provided positioned downstream of the unwinding group 20 before that the web 100 moved along the advancement path 101 , is positioned at a first working station .

In particular, the group 40 for measuring the tension of the web of paper 100 can be associated to a deflection member 35 ' , for example a deflection roll of a series of deflection members 35 of the displacement group 30 , preferably deflection rolls 35 adapted to guide the web of paper 100 along the aforementioned predetermined advancement path 101 . More in detail , the deflection roll 35 ' can be supported by at least one support arm 45 , advantageously by two support arms arranged at opposite sides with respect to the deflection roll 35 ' . The or each support arm 45 can be hinged about an axis 105 parallel to the aforementioned longitudinal axis 110 about which the reel 10 rotates during its unwinding . The or each support arm 45 is , advantageously, associated to a force detection member, for example a load cell 47 . Furthermore, the or each support arm 45 can be associated to a member for detecting the angular position of the same, for example an encoder 46 . In particular, the or each support arm 45 can be kept in a predetermined position by an actuator 43 . In this way, the or each member for detecting the force 47 is able to detect the reaction force of the or each support arm 45 responsive to the force exerted by the same by the deflection roll 35 ' which is function of the tension of the web of paper 100 .

According to the present invention, on the basis of the value of the elongation percentage that is read by the optical detection device 50 on the label 15 , the control unit 300 is adapted to set a predetermined value of the tension, preferably a predetermined range of values of the tension, to which the web of paper 100 can be subj ected to during its movement along the advancement path 101 . In particular, the tension can be controlled setting by the aforementioned actuator 43 , for example a motor, a pneumatic actuator, or other similar devices , a determined intermediate position of the support arm 45. During the unwinding of the reel 10 , a controlled oscillation of the or each support arm 45 about axis 105 will occur, with a determined amplitude ±a with respect to the aforementioned intermediate position . I f , during the unwinding of the reel 10 , the device for detecting the angular position 46 , for example an encoder, detects a deviation from the aforementioned predetermined intermediate position greater than a determined threshold range , the control unit 300 is adapted to operate the unwinding group 20 , more precisely the motor 25 of the same, in order to cause the or each unwinding member 22 and, therefore , the reel 10 , to accelerate or decelerate , in order to bring the value of the tension measured by the force detection member 47 back within a predetermined range of admissible values .

According to the invention, on the basis of the value of the elongation percentage which is read by the optical detection device 50 on the label 15 , the control unit 300 is adapted to set a predetermined value of the force that the actuator 43 has to exert on the web of paper 100 to which corresponds a determined position of the or each support arm 45 and, therefore , a determined tension of the web of paper 100 . In this way, it is possible to control the elongation of the web of paper 100 thus avoiding to have a too high tension applied, for example , to a paper having a high elongation, allowing to avoid the problems above described . Vice versa, it is possible to apply the right tension to a web of paper 100 which is very sti ff and that have a short elongation, and that , preferably, needs a higher tension, obviously, without reaching the maximum tensile stress of the paper same . In an embodiment provided and diagrammatically shown in figure 10 , the displacement group 30 can comprise a first and a second roll 36 and 37 , at least one of which operatively connected to a motor 56 , for example by a transmission belt 57 , which causes it to rotate about a respective rotation axis . Preferably, however, as in the case of figure 10 , both the first roll 36 and the second roll 37 can be motori zed, i . e . connected to the motor 56 . For example, the first roll 36 can be connected to the motor 56 by a transmission belt 57 and can transmit the motion to the second roll 37 by motion transmission gears , advantageously a couple of toothed wheels 58a and 58b, respectively coaxially arranged with respect to the first roll 36 and to the second roll 37 , that cause a rotation of the same in the opposite direction . The aforementioned first and second rolls 36 and 37 are, advantageously, positioned close to , preferably downstream of , a tension measurement group 40 . In particular, at least one of the aforementioned rolls 36 and 37 can be provided with an external surface having a high friction, for example covered by rubber, or knurled . Preferably, the web o f paper 100 can "bandage" at a certain angle the rolls 36 , 37 in order to optimize the traction exerted on the web of paper 100 . In this case , the control unit 300 can be configured to accelerate or decelerate the motor 56 and, therefore, the rolls connected to the same in order to increase or decrease the tension of the web of paper 100 if the values of tension received from the group 40 for measuring the tension do not belong to the aforementioned range of admissible values .

In alternative embodiments , the tension measurement group 40 can be formed by a deflection roll 35 , preferably idle , that is mounted with a fixed axis , that means not mounted on the support arms 45 . In this case , the deflection roll 35 on which the web of paper 100 is wound, can be provided with a load cell which measures the load or force exerted by the web of paper 100 same on the idle roll 35 , to which a respective tension of the paper corresponds .

Advantageously, as diagrammatically shown in figure 11 , a first tension measurement group of the web of paper 100 as described above with reference to figure 10 , can be provided upstream of a section or station 80 of the machine 1 where a predetermined operation is carried out on the worked web of paper 100 , and a second tension measurement group 40b can be provided downstream of the same station 80 . Analogously to what has been described above with reference to figure 9, the first and second tension measurement groups 40a e 40b can comprise a force detection member 47 associated to a respective deflection roll 35 . This can be supported by at least one support arm 45 , preferably by a couple of support arms 45 positioned at opposite sides of the roll 35 ' same . The member for detecting the force 47 , for example a load cell , can be adapted to measure the force of reaction of the or each support arm 45 responsive to the force exerted on the same by the deflection roll 35 ' which is function of the tension of the web of paper 100 . Also in this case an actuator, for example a motor 43 , can be provided arranged to keep the or each support arm 45 in position in such a way that the detection member 47 is able to detect the force of reaction of the or each support arm 45 responsive to the force applied on the same by the deflection roll 35 that is function of the tension of the web of paper 100 . In practice, the higher is the tension on the web of paper 100 the higher will be the force measured by the member for detecting the force 47 .

In an embodiment provided by the invention, a first tension measurement group 40a can be positioned upstream of a printing group to apply a predetermined number of colours , in particular from 1 to 4 , or even more colours , on a web of paper 100 and a second tension measurement group 40b can be positioned upstream of the printing group same . The printers , typically flexographic printers , are known machines and will not be described here in detail .

In addition or alternatively, a first tension measurement group 40a can be positioned upstream and a second tension measurement group 40b can be positioned downstream of an embossing group configured to emboss and j oin together one or more webs 100 of paper . Many embossing devices exist to obtain a great variety of di f ferent products which will not be described in detail here .

According to an embodiment of the invention, on the label 15 at least the number and the position of the or each defect can be indicated as datum or parameter 16 . In this case , the control unit 300 can be arranged to operate the displacement group 30 in such a way to decrease or bring to zero the advancement speed when the or each defect of the web of paper 100 reaches predetermined positions of the aforementioned advancement path 101 .

In the embodiment diagrammatically shown in figure 7 , the paper converting machine 1 comprises a folding or interfolding group configured to fold or interfold a sheet or web of paper 100 according to a predetermined folding or interfolding configuration in such a way to obtain stacks 150 of folded or interfolded products , such as packages of tissue papers , napkins , towels etc . , and wherein on the label 15 as datum or parameter 16 at least the value of the elongation percentage can be indicated . In this case, the control unit 300 can be configured to operate the folding or interfolding group in such a way to avoid that the sheet or the web of paper is subj ected to a tension such to reach the maximum elongation percentage .

Still as diagrammatically shown in figure 7 , the control unit 300 can be configured to store in a database 350 the or each alphabetic and/or numeric character of the or each datum or parameter recogni zed and acquired by the optical detection device 50 .

In a further alternative embodiment of the invention, on the label 15 at least the value o f the paper weight , in particular expressed in g/m ² , can be indicated . In this case , the control unit 300 can be configured to operate the displacement group 30 in order to increase the advancement speed of the web of paper 100 along the advancement path 101 as the paper weight increases and, vice versa, decreasing the advancement speed as the paper weight decreases .

In general , the control unit 300 can compute a maximum threshold value or an optimal production speed, on the basis of one or more parameters read on the label 15 .

Advantageously, the values of the paper weight , the number of veils and the width of the reel 10 detected by the optical detection device 50 on the label 15 , can be used by the control unit 300 to set the tension measurement group 40 , in particular to set a starting value of the aforementioned intermediate position of the support arms 45.

In practice , the control unit 300 according to one or more parameters selected among the value of the elongation percentage, the value of the paper weight , the number of veils and the width of the reel 10 , can compute the optimal reference value of the tension of the web of paper 100 . Advantageously, the central control unit 300 can adj ust and operate the displacement group 30 to keep the tens ion of the web of paper 100 equal to the computed optimal value . In particular, the central control unit , once computed the optimal value of the tension of the web of paper 100 , executes a control algorithm of known type in loop, for example a PI , PID or an algorithm of another type , to keep the tension of the web 100 equal to the optimal value , showing the actual value of the tension by the tens ion measurement group 40 and adj usting the tension by the displacement group 30 .

As diagrammatically shown in the figures 12 and 13 , the aforementioned support group 70 can be conf igured to move , in particular to translate , along a direction axial to the reel 10 . In particular, the optical detection device 50 can be adapted to detect at least the value of the height (H ) of the reel 10 indicated on the label 15 and, in case , to send the same to the control unit 300 . In this case , the control unit 300 can be configured to operate the support group 70 to move , in particular translate , along the axial direction, to move the reel 10 along the longitudinal axis 110 up to positioning the reel 10 same in a predetermined centred position ( Pc ) at which the reel 10 i s axially centred with respect to the machine 1 , that means that the transversal plane 115 of the reel 10 is positioned at the aforementioned centring position Pc ( situation shown in figure 13 with a broken line ) .

In a further alternative embodiment of the invention diagrammatically shown in figure 14 , the machine 1 can be equipped with at least one device for generating a determined vacuum degree, for example a vacuum pump 60 . The device for generating vacuum 60 can be operatively connected to at least one section 80 of the paper converting machine 1 , for example a cutting section at which a cutting roll , or a folding or interfolding section comprising a couple of folding or interfolding counter-rotating rolls can be positioned . In this case, the control unit 300 can be configured to set the aforementioned vacuum degree on the basis of the value of air permeability and/or paper weight detected by the optical detection device 50 on the label 15 .

In a further alternative embodiment of the invention, the control unit 300 can veri fy i f the type of product to be converted by the paper converting line 1 is compatible with the reel 10 mounted on the machine according to one or more parameters selected among the value of the elongation percentage , the value of the paper weight , the number o f veils , the width of the reel 10 , the typology of paper . In case that the reel of paper 10 i s not compatible with the data for producing the paper product , the control unit 300 can generate an alert to advise the worker to mount a suitable reel or to change the type of product to be produced .

The foregoing description exemplary embodiments of the invention will so fully reveal the invention according to the conceptual point of view, so that others , by applying current knowledge , will be able to modi fy and/or adapt for various applications such embodiment without further research and without parting from the invention, and, accordingly, it is therefore to be understood that such adaptations and modi fications will have to be considered as equivalent to the specific embodiments . The means and the materials to reali ze the di f ferent functions described herein could have a dif ferent nature without , for this reason, departing from the field o f the invention . It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation .