Embosser-laminator unit with functional liquid applicator, and method

Abstract

The embosser-laminator unit comprises an embossing roller (21), supported on a stationary supporting structure (45), and an applicator roller (61) adapted to apply a glue on an embossed web-like material sent around the embossing roller (21). The applicator roller (61) is carried by a slide (41) which is movable with respect to the supporting structure (45) to move towards and away from the embossing roller (21). The embosser-laminator further comprises an actuation mechanism (51, 67), adapted to command a movement of juxtaposition and distancing of the slide (41) and the applicator roller (61) with respect to the embossing roller (21), and a position detector device (69), adapted to detect the relative position between the slide and the stationary supporting structure. A detection arrangement (75) is adapted to detect a contact condition between the applicator roller (61) and the embossing roller (21). A method for positioning the applicator roller (61) with respect to the embossing roller (21) is further described.

Description

EMBOSSER-LAMINATOR UNIT WITH FUNCTIONAL LIQUID APPLICATOR,AND METHODDESCRIPTIONTECHNICAL FIELD

[0001] The present disclosure relates to the field of machines for weblike material converting. Embodiments disclosed herein relate in particular to machines for the paper converting and in particular tissue paper converting for the production of toilet paper, paper towels, tissues and paper napkins and similar products.

[0002] Specifically, improvements to embosser or embosser-laminator units for converting a multi-ply web-like material, especially made of tissue paper, are disclosed herein.BACKGROUND ART

[0003] Products made of cellulosic material, for example toilet paper rolls, paper towel, tissues and paper napkins, are produced using a cellulosic web-like material, typically tissue paper, fed by one or more mother reels coming from a continuous production machine.

[0004] In some cases, the parent reels are unwound and rewound into reels or rolls of smaller diametrical and / or axial dimensions into what are called slitter-rewinders or in what are called rewinders.

[0005] The reels coming from the continuous papermaking machine or from the slit- ter-rewinder are intended to feed converting lines for the production of items intended for consumption, for example napkins, tissues or rolls of toilet paper, paper towels and similar.

[0006] The converting line usually contains an unwinding station, adapted to unwind one or more reels of cellulosic web-like material. One or more plies of cellulosic weblike material are fed, along the same path or along separate paths, to machines placed along the converting line downstream of the unwinding station, to undergo one or moreconverting operations, to finally obtain the products intended for sale and consumption.

[0007] Typically, a converting line comprises, downstream of the unwinding station, at least one embosser unit, which carries out an embossing operation on one or more plies forming the continuous cellulosic web-like material. Embossing consists of a permanent deformation of the cellulosic web-like material by passing the cellulosic web-like material into an embossing nip defined between an embossing roller, provided with embossing protuberances, and a pressure roller. The embossing roller is usually a roller made entirely of steel or having at least an external jacket made of steel, or other hard material, provided with said embossing protuberances. The pressure roller is a roller which can have a hard, engraved outer surface with engravings complementary to the embossing protuberances of the embossing roller. In more widespread embodiments, the pressure roller has a smooth outer surface, where smooth is intended as a surface generally free of engravings or protuberances, formed by a yielding layer, preferably an elastically yielding material.

[0008] In use, the pressure roller and the embossing roller are pressed against each other in the embossing nip. If the pressure roller is coated with a yielding material, the pressure between the embossing roller and the pressure roller is such that at least a partial penetration of the embossing protuberances of the embossing roller into the yielding coating of the pressure roller, while the embossing roller and the pressure roller rotate in opposite directions at substantially the same peripheral speed. This causes permanent deformation of the web-like material which is fed through the embossing nip at an advancement speed substantially equal to the peripheral speed of the embossing roller and the pressure roller.

[0009] In some cases, the converting line can comprise an embosser unit having a single embossing roller and a single pressure roller, which form a nip through which the web-like material passes, which can consist of one or more plies of cellulosic fibres.

[0010] More frequently, the converting line can comprise an embosser unit with more than one embossing roller, each cooperating with a respective pressure roller, so as to separately emboss two plies of cellulose fibres, each of which can in turn be madeof one or more layers of cellulosic fibres. An embosser unit of this type is more specifically called "embosser-laminator unit", as it comprises a lamination system, where the two (or more) separately embossed plies are bonded together by means of the application of a functional fluid, by means of mechanical ply-bonding or in other manner. The laminating system can comprise, for example, a nip defined between two opposite and counter-rotating embossing rollers, or between an embossing roller and a laminating roller. The result is a multi-ply embossed cellulosic web-like material.

[0011] In some embodiments, bonding of the plies in the embosser-laminator unit occurs using a glue, which can be in aqueous suspension. More in general, a functional fluid can be used, typically a functional liquid. In some cases, the functional fluid can simply be water, without the addition of glue. The functional fluid has the function of promoting formation of hydrogen bonds between the fibres of the cellulosic layers. Therefore, in the present context "functional fluid" means a generic fluid which, applied as described below, contributes to bonding the plies. The functional fluid is, in this sense, a glue and therefore (unless otherwise indicated) the term glue in the present description and in the claims indicates a fluid, typically in the liquid state, which acts as a functional fluid adapted to obtain, facilitate or promote the bonding of cellulosic plies.

[0012] The embossed cellulosic web-like material which exits from the embosser unit is further converted in converting stations downstream of the embosser unit, for example wound in logs, i.e., rolls with a diameter equal to the diameter of the final rolls and an axial length which is a multiple of the axial dimension of the final rolls. Next, the logs are cut into individual rolls, which are then packaged for transport and distribution. In this case a rewinder is placed in the converting station.

[0013] In other converting lines, a converting station is arranged downstream of the embosser unit, which comprises an interfolding machine, or a cutting and folding machine, to produce paper tissue napkins or towels, which can possibly be interfolded together (in the case of interfolding machines).

[0014] The functional fluid is usually applied to a cellulosic ply after this has been embossed and is still in contact with the respective embossing roller, downstream of the embossing nip formed by the embossing roller and a respective pressure roller. Theapplication of the glue or in general of the functional fluid occurs by means of an applicator roller, which can have an interchangeable plate adapted to allow, for example, the application of the functional fluid according to a given pattern on the embossed layer and more exactly on at least some of the embossed protuberances of the ply. The functional fluid is usually distributed on the applicator roller by means of a dosing roller, for example an anilox roller, which is wetted with functional fluid by continuously rotating in contact with the applicator roller and drawing the functional fluid from a tank.

[0015] To optimise the application of functional fluid, it is advisable for the applicator roller to be at a precisely and stably defined distance from the embossing protuberances of the embossing roller with which the applicator roller cooperates. For this purpose, a functional fluid application nip, or gluing nip, is defined between the applicator roller and the embossing roller, which has a dimension equal to or slightly smaller than the thickness of the ply of cellulosic material at the embossing protrusions, so as to guarantee a contact with minimal pressure between the applicator roller and the embossed ply.

[0016] When the embossing roller, or the applicator roller, or a portion of the latter, for example the plate, is replaced, it is necessary to precisely adjust the mutual distance between the envelope surface of the embossing protuberances of the embossing roller and the envelope surface of the applicator roller.

[0017] EP-A-2815815 discloses an embosser-laminator with a glue applicator unit. The latter is provided with an actuator which pushes the glue applicator roller against the embossing roller around which a cellulosic ply is driven. This known device is configured to continuously control the pressure exerted by the glue applicator roller on the embossing roller during processing of the cellulosic web-like material.

[0018] An object of the subject disclosed herein is to provide an embosser-laminator unit and an adjusting method which allow an easy and automatic adjustment of the mutual position between the applicator roller and the embossing roller, so as to optimise the operation of the embosser-laminator, in terms of the correct application of the glue or functional fluid.SUMMARY

[0019] According to one aspect, disclosed herein is an embosser-laminator unit (hereinafter briefly referred to also simply as "embosser unit"), comprising an embossing roller, supported on a stationary supporting structure and a dispenser for applying a functional liquid to a web-like material guided around the embossing roller. The dispenser comprises an applicator roller, adapted to apply a functional fluid, for example a glue, on an embossed web-like material guided around the embossing roller. The applicator roller is carried by a slide movable on guides defining a prismatic pair or a rotoidal pair, to allow a movement of the slide with respect to the supporting structure so as to move the applicator roller closer and farther away from the embossing roller. The embosser further comprises an actuation mechanism adapted to command a movement of approaching and distancing of the slide and the applicator roller with respect to the embossing roller, and a position detector device adapted to detect the relative position between the slide and the stationary supporting structure. A detection arrangement is adapted to detect a contact condition between the applicator roller and the embossing roller.

[0020] The embosser, or embosser-laminator, thus configured can perform a positioning cycle of the applicator roller with respect to the embossing roller, in which a zero position, i.e., a reference position, is identified, typically a position of mutual contact between the applicator roller and the embossing roller. From such a position, by means of an actuator, the applicator roller is brought to a predetermined distance from the embossing roller, before starting the embosser.

[0021] In some embodiments, the position detector device is carried by the slide or by the stationary supporting structure. In such a case, the embosser unit comprises a first stop, fixed with respect to the stationary structure or to the slide. The position detector device is adapted to cooperate with the first stop, to measure the relative movement between the slide and the stationary supporting structure. In other embodiments, the position detector device can be integrated in the first actuator. In still other embodiments, the position detector device can be an optical device, with an optical source generating a beam hitting a detector which generates photo-currents as a function of the position of the optical beam hitting the detector. In still other embodiments, the position detector device can comprise a laser device, or a video camera.

[0022] The embosser unit can further comprise a control unit functionally connected to the first actuator, the position detector device and the detection arrangement. Functionally connected means that the control unit receives signals from the detector or transducer devices and sends commands to the actuators. The control unit can be programmed to command a controlled movement of the slide away from the embossing roller starting from a zero position, i.e., a reference position, defined by the position in which the applicator roller comes into contact with the embossing roller.

[0023] In some embodiments, the detection arrangement, which detects the contact condition between the applicator roller and the embossing roller, can comprise at least one load cell adapted to detect a force exerted on the applicator roller by the contact of the applicator roller with the embossing roller. Preferably, two load cells are provided, associated for example with bearings supporting the applicator roller.

[0024] In other embodiments, the detection arrangement, which detects the contact condition between the applicator roller and the embossing roller, can comprise detectors which cause a stop in the advancement of the applicator roller towards the embossing roller when the actuator is activated to command the approaching movement of the slide carrying the applicator roller towards the embossing roller.

[0025] In particularly simplified embodiments, the actuation mechanism can comprise a single actuator which performs all the mutual approaching and distancing movements between the applicator roller (and the slide carrying it) and the embossing roller. In such a case, for example, an electric actuator can be used. The position detector device can in such a case be incorporated in the single actuator.

[0026] In more efficient embodiments, the actuation mechanism of the embosserlaminator unit can comprise a first actuator, which forms for example a thrust actuator, adapted to bring the slide into a position approaching the embossing roller. The actuation mechanism further comprises a second actuator adapted to command a controlled movement of the slide, and therefore of the applicator roller, with respect to the embossing roller. In practice, in such a case the embosser-laminator unit comprises two actuators. The first actuator (thrust actuator) commands an approaching and distancing movement of the slide to / from the embossing roller to push and maintain the slide in a stop position. The distancing movement actuated by the first actuator can serve forexample to completely distance the functional fluid dispenser from the first embossing roller. The second actuator serves to impose a controlled approaching and distancing movement of the slide and therefore of the applicator roller with respect to the embossing roller starting from an approached position which can be reached with the first actuator.

[0027] In this embodiment, a second stop can be provided, carried by the slide or by the stationary supporting structure and cooperating with a third stop, carried by the stationary structure or by the slide. The second actuator is adapted to command a movement of the second stop, which causes a movement of the slide with respect to the stationary supporting structure when the second stop is in contact with the third stop.

[0028] The second actuator can be functionally connected to the control unit and the control unit is programmed to command the controlled distancing movement of the slide with respect to the embossing roller by means of the second actuator starting from a zero position, i.e., a reference position, which can be identified by means of a previous step of controlled approach of the applicator roller to the embossing roller commanded by the second actuator.

[0029] Further advantageous features and embodiments of an embosser unit disclosed herein are indicated in the attached claims and described in detail below, with reference to the attached drawings.

[0030] According to a different aspect, a method is disclosed herein for adjusting, in an embosser-laminator, the relative position between an embossing roller carried by a stationary supporting structure and an applicator roller carried by a slide which is movable with respect to the stationary supporting structure, comprising the following steps: approaching the applicator roller to the embossing roller until the applicator roller comes into contact with the embossing roller, detecting the contact by means of a detection arrangement and setting the position in which the applicator roller touches the embossing roller as the reference position; moving the applicator roller away from the embossing roller measuring the movement by means of a position detector device; stopping the applicator roller when the position detector device detects that a predefined distance from the reference position has been reached.

[0031] The contact between the embossing roller and the applicator roller can be detected by means of at least one load cell, or by means of a position detector device, i.e., an encoder, whose signal allows to identify when the approaching movement of the applicator roller to the embossing roller stops due to the mutual contact between such rollers.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Embodiments are illustrated in the attached drawing, in which:Fig. l shows an embosser-laminator unit;Fig. lA shows a schematic enlargement of the detail indicated with A in Fig.l; Fig. IB shows a schematic enlargement of the detail indicated with B in Fig. l;Fig.2A shows a detail of an embossing roller and the functional fluid dispenser in a first position; andFig.2B shows a detail of an embossing roller and the functional fluid dispenser in a second position.DETAILED DESCRIPTION

[0033] In the embodiment illustrated in Fig. l, an embosser-laminator unit 5 is shown (in the present context also briefly referred to as "embosser unit") comprising a first embossing roller 21 provided with embossing protuberances 21P (Fig. lA) and cooperating with a first pressure roller 23, which can have an outer surface 23A consisting up of a coating of yielding material, in particular elastically yielding, for example rubber. The embosser-laminator unit 5 also comprises a second embossing roller 25 provided with embossing protuberances 25P (Fig. IB) and cooperating with a second pressure roller 27, which can have an outer surface 27A consisting of a coating of yielding material, in particular elastically yielding, for example rubber.

[0034] In the illustrated embodiment, the first pressure roller 23 is supported at the ends thereof by respective pivoting arms 20, hinged by means of hinges 22 to the fixed supporting structure 45. Actuators 24, for example a pair of pneumatic or hydraulic cylinder-piston actuators, act on the pivoting arms 20 to press the pressure roller 23 against the embossing roller 21.

[0035] Similarly, in the illustrated embodiment, the second pressure roller 27 is supported at the ends thereof by respective pivoting arms 26, hinged by means of hinges 28 to the fixed supporting structure 45. Actuators 30, for example a pair of pneumatic or hydraulic cylinder-piston actuators, act on the pivoting arms 26 to press the pressure roller 27 against the embossing roller 23.

[0036] A first embossing nip 31 is formed between the first embossing roller 21 and the first pressure roller 23, and into which the first ply VI is fed. A second embossing nip 33 is formed between the second embossing roller 25 and the second pressure roller 27, and into which the second ply V2 is fed. The two embossed plies are bonded together in a laminating nip which can be formed between the first embossing roller 21 and the second embossing roller 25, for example in the case of what is called a a tip- to-tip embosser unit. Alternatively, as illustrated in Fig.1, the embossed ply V2 can be detached from the second embossing roller 25 and guided around the first embossing roller 21, to pass together with the ply VI through a laminating nip 36, formed between the first embossing roller 21 and a laminating roller 35.

[0037] In the illustrated embodiment, the laminating roller 35 is supported at the ends thereof by respective pivoting arms 34, hinged by means of hinges 38 to the fixed supporting structure 45. Actuators 40, for example a pair of pneumatic or hydraulic cylinder-piston actuators, act on the pivoting arms 34 to press the laminating roller 35 against the embossing roller 21.

[0038] To join the two plies VI, V2, a functional liquid can be used, for example a glue, applied to the ply VI, when this is guided around the first embossing roller 21 and engaged therewith after having been permanently deformed in the embossing nip 31, so that embossed protuberances are formed in the ply VI and are adherent to the embossing protuberances 21P of the first embossing roller 21.

[0039] To apply a functional liquid, for example, a dispensing unit for glue or other functional liquid, for example simply water, is provided. In the following, this dispensing unit of adhesive or other functional fluid will be referred to simply as "dispenser" or "dispensing unit" and is indicated overall with 37 in Fig. l.

[0040] The main components of the dispenser 37 are visible in greater detail in Figs. 2 A and 2B.

[0041] In embodiments described herein, the dispenser 37 comprises a slide 41 guided along guides 43, which can be integral with a stationary supporting structure 45 which supports the embosser-laminator unit 5. The slide 41 can be engaged with the guides 43 by means of skids 47. In other embodiments, it is possible to constrain the dispensing group 37 to the stationary supporting structure 45 by means of a rotoidal joint so as to rotate the dispensing unit 37 around a rotation axis and cause it to move towards and away from the first embossing roller 21.

[0042] In the illustrated embodiment, the slide 41 is divided into two slide portions, and more precisely a first slide portion 41 A and a second slide portion 4 IB, for the purposes which will become clear below. In other embodiments, not shown, the slide 41 can be monolithic. The first slide portion 41 A and the second slide portion 41B are located at a mutual distance which can be adjusted by means of stops 49A, 49B. One of the two stops is mounted on one of the two slide portions 41 A, 4 IB and can be fixed with respect to such a slide portion. The other stop is carried by the other slide portion and can be adjustable with respect to such a slide portion on which it is mounted. By acting on the adjustable stop (in the illustrated example the stop 49A) the mutual distance of the two slide portions 41 A, 41B can be adjusted.

[0043] In the illustrated embodiment the two slide portions 41A, 41B are pushed towards the embossing rollers 21, 25 by means of a first actuator. In embodiments, the first actuator can comprise a linear actuator or a pair of linear actuators, one on each side of the slide 41. Each linear actuator is indicated with 51. For example, the linear actuator or each linear actuator 51 can be a cylinder-piston actuator. Each linear actuator 51 can be constrained to the slide portion 41 A and to a point 53 integral with the stationary supporting structure 45. By acting on the linear actuators 51 and commanding the retraction thereof, the slide 41 is pushed towards the embossing rollers 21, 25, into a position which is defined in the manner which will be described below. If, as in the illustrated example, the slide 41 is divided into two portions 41 A, 41B, by anchoring the actuator or actuators 51 to the slide portion 41 A farthest from the embossing rollers 21, 25, it is possible to move both slide portions 41A, 41B into a maximum approaching position to the embossing rollers 21, 25, with the slide portion 41A pushed abutting against the slide portion 41B thanks to the stops 49A, 49B.

[0044] The dispenser 37 can comprise a dosing roller, hereinafter referred to asanilox roller, indicated with 57, which withdraws functional liquid, for example a glue, from a tank or other source of functional liquid indicated with 59. The anilox roller 57 transfers the functional liquid to an applicator roller 61, which can be equipped with an interchangeable plate, not shown in detail. The applicator roller, or plate roller, 61 is configured to transfer functional liquid received from the anilox roller 57 to the embossed ply VI and more precisely onto at least some of the embossed protuberances of such a ply VI which are engaged to the embossing protuberances 2 IP of the first embossing roller 21. For this purpose, the applicator roller 61 is located with the outer surface thereof, on which the anilox roller 57 doses the functional liquid, at a distance from the heads of the embossing protuberances 2 IP which is equal to or preferably less than the thickness of the ply VI at the embossing protuberances 2 IP. This distance is adjusted in the manner described below.

[0045] The provision of two slide portions 41A, 41B and of a system of stops 49A, 49B in combination with the linear actuator 51 allows the distance between the axis 61A of the applicator roller 61 and the axis 57A of the anilox roller 57 to be adjusted (acting on the adjustable stop 49A). Thereby, acting on the stop 49A the quantity of functional liquid transferred from the anilox roller 57 to the applicator roller 61 can be dosed.

[0046] In other embodiments, not shown, the slide 41 can be made monolithic and the adjustment of the distance between the axes 57A and 61 A can be performed for example by envisaging that the anilox roller 57 is carried by supports which are adjustable with respect to the slide 41.

[0047] To set the correct position of the applicator roller 61 with respect to the embossing roller 21, a second actuator can be provided, which adjusts the position of a movable stop, which cooperates with a respective fixed stop. By keeping these movable and fixed stops in contact with each other and moving the movable stop, the distance between the applicator roller 61 and the first embossing roller 21 is adjusted, ensuring that one of the two stops is integral with the slide 41 (and more precisely the slide portion 4 IB) and the other is integral with the stationary supporting structure 45.

[0048] In the illustrated embodiment, a fixed stop 63 is envisaged, integral with the stationary supporting structure 45 and cooperating with a movable stop 65, carried bythe slide 41, and more precisely by the portion 41B of the slide 41.

[0049] In the illustrated embodiment, the movable slide 65 is controlled by a second actuator 67. In some embodiments, the second actuator 67 can be an electric actuator. The double arrow f65 indicates the movement imparted by the actuator 67 to the stop 65. The actuator 67 and the arrangement of stops 63, 65 can be double, one on each side of the slide 41. In other embodiments, a single actuator 67 with a single arrangement of stops 63, 65 is provided.

[0050] The arrangement of stops and actuator can be reversed. In such a case, the fixed stop is integral with the slide 41 and more precisely with the slide portion 4 IB and is "fixed" in the sense that it does not move with respect to the slide carrying it. The movable slide can be carried by the stationary supporting structure 45 and is "movable" in the sense that it moves, under the command of the actuator 67, with respect to the stationary supporting structure 45.

[0051] In both cases, keeping the movable stop 65 and the fixed stop 63 in contact with each other and acting on the actuator associated with the movable stop, it is possible to move the slide 41 (and more precisely the slide portion 4 IB) with respect to the stationary supporting structure 45 and therefore with respect to the first embossing roller 21 in a controlled manner. Since the axis 61A of the applicator roller 61 is in a fixed position with respect to the slide 41 (and more precisely with respect to the slide portion 4 IB), by means of the actuator 67 it is possible to adjust the distance between the cylindrical surface of the applicator roller 61 and the cylindrical surface of the first embossing roller 21, which cylindrical surface is in practice the surface which envelops the embossing protuberances 2 IP. If the embossing protuberances 2 IP are of different heights from each other, the cylindrical surface of the first embossing roller 21 is intended as the enveloping surface of the embossing protuberances of greater height.

[0052] The arrangement described above can be associated with a detector device which detects the relative position between the slide 41 (and more in particular slide portion 41B) and the embossing roller 21, i.e., the relative position between the slide 41 and the stationary supporting structure 45.

[0053] In the illustrated embodiment, this position detector device comprises an en-coder. The encoder can be associated with the actuator 67, for example it can be integrated therein. Conversely, in the illustrated embodiment an encoder 69 is provided outside the actuator 67 and carried by the slide 41, and more precisely integral with the slide portion 41B. In some embodiments the encoder 69 can cooperate with a fixed stop 71. In this embodiment, the fixed stop 71 is integral with the stationary supporting structure 45. For example, the stop 71 can be integral with the stop 63 or integral therewith. In other embodiments, the position detector device can comprise a sensor or transducer adapted to measure a distance, even without contact, for example a capacitive or eddy current system.

[0054] In other embodiments, the encoder 69 can be carried by the stationary supporting structure 45 and the stop 71 can be integral with the slide 41 (and more precisely with the slide portion 4 IB).

[0055] The use of an encoder integrated in the actuator 67, or outside the actuator and cooperating with a respective stop 71, can be particularly advantageous as it constitutes a simple device for detecting the position of the slide 41, and of the applicator roller 61, with respect to the first embossing roller 21. However, other position detector devices or transducers can also be used. For example, a capacitive sensor can be provided. In some embodiments, a laser device can be provided, with an emitter / receiver integral with the slide portion 4 IB and a reflecting surface integral with the stationary supporting structure 47, or vice versa. In still further embodiments, the mutual distance between slide 41 (or slide portion 4 IB) and first embossing roller 21 can be detected by means of a video camera and an image processing system.

[0056] Instead of a contact encoder, like the one illustrated, an encoder of another type can be used, for example an encoder which uses an optical emitter in combination with a detector which generates photo-currents depending on the position of a light spot generated by the optical emitter onto a detectable surface of the detector.

[0057] In some embodiments, one or more force sensors are associated with the applicator roller 61, referred to herein as load cells for simplicity. Such a term indicates any transducer device adapted to detect a force and emit a signal, typically an electrical signal, as a function of the detected force. At least one load cell is associated with the applicator roller 61 so as to detect a force exchanged between the applicator roller 61and the first embossing roller 21, when the applicator roller 61 is in contact with the first embossing roller 21

[0058] For a more precise measurement, two load cells can be provided, one on each support with which the applicator roller 61 is brought to the slide 41, i.e., by the slide portion 41B. In Figs. 2A, 2B a single load cell 75 is schematically indicated.

[0059] Fig.2A schematically indicates a control unit 77 functionally connected to the encoder 69 (or other generic position detector device), see connection C, and with the load cell(s) 75, see connection D, to receive signals related to the mutual position between the slide 41 (and thus the applicator roller 61) and the first embossing roller 21, and related to the contact force between the applicator roller 61 and first embossing roller 21. The control unit 77 is also interfaced (connection E) with the actuator 67.

[0060] The set of devices and members described so far serves to adjust the position of the applicator roller 61 with respect to the first embossing roller 21 with the following procedure, which can be performed whenever it is necessary to adjust such a position, for example after changing a plate fixed on the applicator roller 61, after replacing the first embossing roller 21, or for any other reason.

[0061] In a first step, the movable stop 65 is extracted by means of the actuator 67 and the actuator 51 moves the slide 41 towards the embossing rollers 21, 25 until the movable stop 65 is in contact with the fixed stop 63.

[0062] At this point, the actuator 51 is kept active, in the sense that it continues to keep the slide 41 in the maximum approach position to the embossing rollers 21, 25, allowed by the presence of the pair of stops 63, 65. The actuator 67 is then activated, which begins to gradually retract the stop 65. If the actuators 67 and the stops 65, 63 are double, the command is given by the control unit 77 to both actuators 67.

[0063] The retraction of the stops 65 causes a gradual approach of the cylindrical surface of the applicator roller 61 to the cylindrical surface of the first embossing roller 21. The gradual approaching movement is obtained in the same manner even if the movable stop 65 is carried by the stationary supporting structure 45 and the fixed stop 63 is integral with the slide 41 (i.e., with the slide portion 41B).

[0064] This movement is continued until the control unit 77 detects a mutual contactbetween the cylindrical surface of the applicator roller 61 and the cylindrical surface of the first embossing roller 21. In the illustrated embodiment, this contact can be detected by means of the signal generated by the load cell(s) 75 (signal D). In fact, the mutual contact between the first embossing roller 21 and the applicator roller 61 generates a force on each support of the applicator roller 61, detected by the load cell 75.

[0065] In other embodiments, the mutual contact can also be detected indirectly. In fact, when the applicator roller 61 contacts the first embossing roller 21, this contact hinders further advancement of the slide 41 towards the embossing rollers 21, 25, along the guides 43. This stop can be detected by means of the encoder 69, or other position detector device as mentioned above.

[0066] For this purpose, the system can operate as follows. The movable stops 65 are extracted and brought into contact with the stops 63 and the encoder 69 is brought into contact with the stop 71. The control unit 77 sends a gradual retraction command of the movable stops 65. Until the applicator roller 61 touches the first embossing roller 21, the encoder generates a movement (or position) signal which varies over time, corresponding to the retraction movement of the movable stops 67. In other words: each movement of the movable stops 63 corresponds to a movement detected by the encoder 69 (or other device adapted to such a function).

[0067] When the applicator roller 61 touches the first embossing roller, the retraction movement of the movable stops 65 continues, but the position detector device (i.e., the encoder 69 or other device) no longer detects a variation in the mutual position between the applicator roller 61 and first embossing roller 21, or detects a smaller variation, for example due to the yielding of the outer surface of the applicator roller 61. This condition is indicative of a contact between the applicator roller 61 and the first embossing roller 21.

[0068] In both embodiments, the embosser-laminator generally comprises a detection arrangement adapted to detect a contact condition between the applicator roller 61 and the first embossing roller 21.

[0069] Regardless of the technique used, the control unit 77 detects the instant in which contact occurs between the first embossing roller 21 and the applicator roller 61. This position is detected by the encoder 69, or other position detector device, andis taken as a zero value.

[0070] The working position of the applicator roller 61 cannot be this contact position, since it would exert excessive pressure on the first embossing roller 21. The working position is set at this point by moving the slide 41 (or more precisely the slide portion 4 IB) backwards from the zero position defined above by an amount equal to the desired distance between the cylindrical surface of the applicator roller 61 and the cylindrical surface of the first embossing roller 21. The backward movement is commanded by the control unit 77 which activates the actuator 67, causing a reversal of its movement from the zero position reached as described above. By means of the encoder 69, the movement in the distancing direction is detected and this data is communicated to the control unit 77, which stops the actuator 67 when a movement equal to the desired mutual distance between the applicator roller 61 and the first embossing roller 21 has been performed. Typically, this retraction stroke will be equal to the thickness of a ply VI or slightly less.

[0071] The procedure described above is summarized in Figs.2A, 2B: in Fig.2A the slide 41 is spaced from the embossing rollers 21, 25, the movable stop 65 is extracted and the applicator roller 61 is spaced from the first embossing roller 21. Fig.2B illustrates the instant of contact between the applicator roller 61 and the first embossing roller 21 (zero point). From this moment, the movable stops 65, which have been retracted passing from Fig. 2A to Fig.2B, begin to be extracted until reaching the required distance between the cylindrical surface of the applicator roller 61 and the cylindrical surface of the first embossing roller 21.

[0072] In the described embodiment, two actuators (or pairs of actuators) 51 and 67 are provided: the first actuator 51 keeps the stop 65 in contact with the stop 63; the second actuator moves the stop 65 to translate the slide 41 first towards and then away from the first embossing roller 21. By using a thrust actuator (for example a hydraulic or pneumatic cylinder-piston) for the first actuator 51 and an electronically controlled electric actuator for the second actuator, an extremely accurate control is obtained with a limited cost structure.

[0073] In theory, a single actuator or pair of actuators 51 could be used, in combination with a detector device which detects the relative position between the stationarysupporting structure 45 (and thus the first embossing roller 21) and the slide 41, and in particular the slide portion 4 IB, and in further combination with a contact condition detection arrangement, adapted to detect a contact condition between the applicator roller 61 and first embossing roller 21. The single actuator 51 approaches the slide 41 and thus the applicator roller 61 until it contacts the first embossing roller 21. Once this position has been reached, which is assumed by the control unit 77 as the zero point, the actuator distances the slide 41 (slide portion 4 IB) in a controlled manner and thus the applicator roller 61 from the first embossing roller 21 by a predefined amount which corresponds to the desired distance between the cylindrical surface of the applicator roller 61 and the cylindrical surface of the first embossing roller 21.

[0074] Thereby, the mutual positioning between the applicator roller 61 and the embossing roller 21 is achieved, which from this moment can be modified at will by an operator by means of a human-machine interface (HMI) schematically indicated in Fig.2A with 78, or can be varied automatically by the control unit 77 according to the type of product which must be made or according to the quality of the product produced at that moment.

Claims

Claims1. An embosser-laminator unit (5), comprising: a first embossing roller (21), supported on a stationary supporting structure (45), and a first pressure roller (23), supported on the stationary supporting structure (45), cooperating with the first embossing roller, and defining with the first roller embosser (21) a first embossing nip (31) for a first web-like material (VI); a dispenser (37) adapted to dispense a functional fluid, having an applicator roller (61) adapted to apply the functional fluid on the first embossed web-like material (VI), guided around the first embossing roller (21); wherein the applicator roller (61) is carried by a slide (41) which is movable with respect to the supporting structure (45) to move towards and away from the first embossing roller (21); an actuation mechanism (51 , 67) adapted to command a movement of approaching and distancing of the slide (41) and the applicator roller (61) with respect to the first embossing roller (21); a position detector device (69), adapted to detect the relative position between the slide (41) and the stationary supporting structure (45); a contact condition detection arrangement (75), adapted to detect a contact condition between the applicator roller (61) and the first embossing roller (21).

2. The embosser-laminator unit (5) comprising a second embossing roller (25), supported on the stationary supporting structure (45), and a second pressure roller (27) supported on the stationary supporting structure (45), cooperating with the second embossing roller (25), and defining with the second embossing roller (25) a second embossing nip (33) for a second web-like material (V2).

3. The embosser-laminator unit (5) of claim 1 or 2, comprising at least one of the following features: each pressure roller (23, 27) is supported by a respective pair of pivoting arms, hinged to the supporting structure and operated by respective actuators, to be pressed against the respective embossing roller;each pressure roller (23, 27) is coated with an elastically yielding material, such that the pressure between the embossing roller (21, 25) and the respective pressure roller (23, 27) is such as to cause at least partial penetration of embossing protuberances (2 IP; 25P) of the respective embossing roller (21, 25) in the elastically yielding coating of the corresponding pressure roller (23, 27), while the embossing roller (21, 25) and the pressure roller (23, 27) rotate in opposite directions at substantially the same peripheral speed; the first embossing roller (21) cooperates with a laminating roller (35), defining with the first embossing roller (23) a laminating nip (36), through which the first web-like material (V2) and the second web-like material (V2) pass; and the first embossing roller (21) cooperates with the second embossing roller (25), defining therebetween a laminating nip through which the first web-like material (VI), embossed between the first embossing roller (21) and the first pressure roller (23), and the second web-like material (V2), embossed between the second embossing roller (25) and the second pressure roller (27), pass.

4. The embosser-laminator unit (5) of any one of the preceding claims, wherein the position detector device (69) is carried by one of said slide (41) and said stationary supporting structure (45) and is adapted to cooperate with a fixed reference, which is stationary with respect to the other of said slide (41) and with respect to said stationary supporting structure (45), to measure the relative movement between the slide (41) and the stationary supporting structure (45).

5. The embosser-laminator unit (5) of claim 4, wherein the fixed reference is a stop (71) with which the position detector device (69) comes into contact.

6. The embosser-laminator unit (5) of claim 4 or 5, wherein the position detector device (69) is carried by the slide (41) and the first stop (71) is fixed with respect to the stationary supporting structure (45).

7. The embosser-laminator unit (5) of one or more of the preceding claims, further comprising a control unit (77) functionally connected: to the actuation mechanism (51, 67), to the position detector device (69), and to the contact conditiondetection arrangement (75); wherein the control unit (77) is programmed and configured to command a controlled movement of the slide (41) away from the first embossing roller (21) by means of the actuation mechanism (51, 67), starting from a zero position defined by the position in which the applicator roller (61) comes into contact with the first embossing roller (21).

8. The embosser-laminator unit (5) of claim 7, wherein the control unit (77) is configured to perform the following steps: by means of the actuation mechanism (51, 67), bringing the applicator roller (61) closer to the first embossing roller (12) until the applicator roller (61) comes into contact with the first embossing roller (21), detecting the contact by means of the contact detection arrangement (75), and set the position in which the applicator roller (61) touches the first embossing roller (21) as the reference position; by means of the actuation mechanism (51, 67), moving the applicator roller (61) away from the first embossing roller (21), measuring the movement by means of the position detector device (69); stopping the applicator roller (61) when the position detector device (69) detects that a predetermined distance from the reference position has been reached.

9. The embosser-laminator unit (5) of any one of the preceding claims, wherein the contact condition detection arrangement (75) comprises at least one load cell adapted to detect a force exerted on the applicator roller (61) by the first embossing roller (21).

10. The embosser-laminator unit (5) of claim 9, comprising two load cells (75), each associated with a respective support of the applicator roller (61).

11. The embosser-laminator unit (5) of any one of the preceding claims, wherein the actuation mechanism comprises at least one actuator (51) adapted to bring the first embossing roller (21) and the slide (41), with the applicator roller (61), closer and farther away from each other in a controlled manner.

12. The embosser-laminator unit (5) of any one of claims 1 to 11, wherein the actuation mechanism comprises: a first thrust actuator (51), adapted to push the slide (41) towards a position approaching the first embossing roller (21); and a second actuator (67), adapted to command a controlled movement of the slide (41) towards and away from the first embossing roller (21).

13. The embosser-laminator unit (5) of claim 12, comprising a second stop (65), carried by one of said slide (41) and said stationary supporting structure (45) and cooperating with a third stop (63), carried by the other of said slide (41) and said stationary structure (45), the second actuator (67) being adapted to command a movement of the second stop (65); wherein the movement of the second stop (65) causes a movement of the slide (41) with respect to the stationary supporting structure (45) when the second stop (65) is in contact with the third stop (61).

14. The embosser-laminator unit (5) of claim 13, wherein the third stop (63) is carried by the stationary structure (45); and wherein the second stop (65) and the second actuator (67) are carried by the slide (41).

15. The embosser-laminator unit (5) of claim 12, 13 or 14, when dependent at least on claim 7, wherein the second actuator (67) is functionally connected to the control unit (77) and the control unit (77) is programmed to command the controlled movement of the slide (41) towards and away from the first embossing roller (21) by means of the second actuator (67).

16. The embosser-laminator unit (5) of any one of claims 12 to 15, wherein the position detector device is integrated in the second actuator (67).

17. The embosser-laminator unit (5) of any one of claims 12 to 16, wherein the second actuator (67) is an electric actuator.

18. The embosser-laminator unit (5) of any of claims 13 to 17, wherein the first stop (71) and the third stop (63) are integrated with each other.

19. The embosser-laminator unit (5) of claim 11, wherein the position detector device is integrated in said at least one actuator (51).

20. A method for adjusting, in an embosser-laminator (5), the relative position between a first embossing roller (21) carried by a stationary supporting structure (45) and an applicator roller (61), carried by a slide (41), which is movable with respect to the stationary supporting structure (45), and adapted to apply a functional fluid to an embossed web-like material guided around the first embossing roller (21); wherein the method comprises the following steps: bringing the applicator roller (61) closer to the first embossing roller (12) until the applicator roller (61) contacts the first embossing roller (21), detecting the contact by means of a contact detection arrangement (75), and setting the position in which the applicator roller (61) touches the first embossing roller (21) as the reference position; moving the applicator roller (61) away from the first embossing roller (21) measuring the movement by means of the position detector device (69); stopping the applicator roller (61) when the position detector device (69) detects that a predetermined distance from the reference position has been reached.

21. The method of claim 20, wherein the contact between the first embossing roller (21) and the applicator roller (61) is detected by means of at least one load cell (75).

22. The method of claim 21, wherein the load cell is associated with at least one support of the applicator roller (61).

23. The method of claim 20, 21, or 22, wherein the position detector device (69) is mounted on the slide (41) or the stationary supporting structure (45), and cooperates with a stop (71) mounted on the stationary supporting structure (45) or on the slide (41).

24. The method of any one of claims 20 to 23, comprising the following steps: pushing the slide (41) towards the first embossing roller (21) by means of a first actuator (51), the first actuator keeping the slide juxtaposed to a stop (63) integral with the stationary load-bearing structure (45); using a second actuator (67), moving theapplicator roller (61) closer to the first embossing roller (21) until the applicator roller (61) contacts the first embossing roller (21); when the contact is detected between the applicator roller (61) and the first embossing roller (21), moving the slide (41) and the applicator roller (61) away from the first embossing roller (21) by means of the second actuator (67) up to a preset distance between the applicator roller (61) and the first embossing roller (21).

25. The method of claim 24, wherein the second actuator (67) moves a movable stop (65) carried by the slide (41) or by the stationary supporting structure (45) and cooperating with a fixed stop (63) carried by the stationary supporting struc- ture (45) or by the slide (41).

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