ES2965263T3 - Film rewinding machine comprising a misalignment detector and misalignment detection procedure in a film rewinding machine - Google Patents

Abstract

Film rewinding machine with misalignment detector comprising a rewinding station (10), connected to a transport track (3) of a film web (1), including at least one rewinding shaft (11a, 11b) configured to support and rotate at least one core. winding said at least one strip of film (1) around the core forming a roll (4); wherein the machine further comprises at least one laser rangefinder (20) configured to be placed in a measuring position and to project a laser beam directed towards at least one rewinder axis in a plane perpendicular to the at least one rewinder axis, in a displacement distance in a transverse direction over at least one predefined edge position, the laser rangefinder (20) being configured to detect any edge misalignment in the transverse direction (TD) equal to or greater than said compensation distance. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Film rewinding machine comprising a misalignment detector and misalignment detection procedure in a film rewinding machine

Technical field

The present invention is directed towards a film rewinding machine comprising a misalignment detector and a misalignment detection method for a film rewinding machine.

A film rewinding machine is a machine that transports a film web in a transport direction through a transport path reaching a rewinding station, where the film web is wound around a core to form a roller.

The machine can include several stations in successive segments of the transport path to carry out different operations on the film web, such as cutting, printing, laminating, among others.

The misalignment detector detects a side edge misalignment of the side edges of the film webs wound on the roller, resulting in a problem known as shrinkage.

State of the art

Rewinding machines are already known that receive one or more webs of film from a film feeder to rewind one or more rollers simultaneously.

In such machines, said film feeder transports the tensioned film web or webs through a defined transport path between parallel feeder shafts to a rewind station where each film web is wound around a supported core. on a winding tree forming a roller. The film material constituting the film web is fed into the film feeder from a unwinding roller supported on a unwinding shaft.

Precisely controlling the tension of the film material spanning between the unwind roller and rewind rollers is critical to ensure proper cutting and rewinding without edge misalignment, and change in diameter of the unwind roller and roll. of rewinding make such control very difficult. This is especially so in the case of lightweight web stretchable materials such as acetate. Generally, a relatively large amount of tensile force and resulting tension in the web are required to unwind the web from the unwind roller. The amount of tensile force required increases as the diameter of the unwinding roller decreases and the resulting leverage force decreases.

If the change in tensile forces required to unwind the film material is not properly coordinated with the change in diameter of the unwind roller, then over-rotation may occur and the film web may zigzag laterally, or the tension may be uneven. throughout the winding operation, producing changes in the width of the elastic materials, producing uneven rewind rollers. The resulting product rolls are not uniformly edge-aligned but instead have a collapsed or other undesirable configuration.

Typically, such problems are detected manually by an experienced machine operator who observes the side surfaces of the rewind rollers and determines adjustments to the machine's operating parameters based on his experience. But this process requires expert and highly trained personnel, takes a long time and produces different results depending on the operator in charge of the machine.

Various devices for detecting edge misalignments on a roller using light are also known, for example from KR20120023428A and KR20170022154A. Both documents describe the use of a light beam perpendicular to the side surface of a roller to detect unevenness of said side surface indicative of an edge misalignment of the wound film web.

When there are multiple rollers on the same axis, the solution described in these documents makes it necessary to place the sensor between two rollers.

Documents KR19970047895A and WO2020046010A1 describe an alternative solution for detecting an edge misalignment on a roller, using an oblique light and a camera facing the side surface of the roller to detect shadows cast by the edge misalignments. This detection system presents problems similar to those of the system described above. US 6595460 discloses another example of an edge alignment system in a printing unit.

The present invention solves the above and other problems.

Brief description of the invention

The present invention is directed, according to a first aspect, to a film rewinding machine comprising a misalignment detector.

The proposed machine comprises, in a manner known in the state of the art:

• a film feeder configured to provide a tensioned film web of a flexible sheet material transported in a transport direction along a transport path by maintaining two opposite side edges of said film web at predefined edge positions in a direction transversely perpendicular to the direction of transport, the film web feeder including an automatic film tensioning device to maintain the film web at a constant tension during its transportation;

• a rewinding station, connected to the transport path to receive said at least one tensioned film web, the rewinding station including at least one rewinding shaft with an axis parallel to the transverse direction and configured to support and rotate the at least one core for winding said at least one film strip around the core that forms a roller.

Accordingly, the film feeder provides the rewinding station with a continuous supply of a tensioned film web transported in a transport direction following a transport path. Typically, the film feeder comprises a plurality of feeding shafts parallel to each other that support the film web that define said transport path.

The film rewinding machine may be, for example, a slitting machine, a laminating machine, or a printing machine, such as a digital printing machine, a flexographic printing machine or an offset printing machine.

The flexible sheet material may be, for example, a plastic film material which typically has some degree of elasticity, or a paper material.

Said film web is transported through the transport path maintaining two opposite side edges of the film web at corresponding predefined edge positions in a transverse direction.

Said transverse direction is a direction perpendicular to the transport direction and coplanar with the film web. Normally, the transverse direction is parallel to the feeder shafts. Accordingly, each lateral edge of the film web is kept, during its transportation along the transport path, in a plane perpendicular to said feed shafts, the film web being held between two of said mutually parallel planes spaced a distance apart. distance from the width of the film strip.

The rewind station includes at least one rewind shaft, typically parallel to the feed shafts, supporting at least one core connected to one end of the film web.

When said at least one rewinding tree is several rewinding trees, all said rewinding trees are parallel to each other.

Typically, the rewinding shaft includes a retaining device configured to retain the core in a predefined position in the transverse direction and also in an angular position, such that driven rotation of the rewinding shaft results in rotation of the at least one core, produces the winding of the film band around the core, generating a roller.

Preferably, the driven rotation of the rewinding shaft is coordinated, by a control device, with a driven rotation of at least some of the feed shafts to maintain the film web at a predefined tension, taking into account the variation of the diameter of the rolled roller.

The proposed invention also includes the following elements, not known in the state of the art:

• at least one laser rangefinder configured to be located in a measurement position and to project a laser beam directed towards the at least one rewind shaft in a plane perpendicular to the at least one rewind shaft when in said measurement position, being said plane at a distance offset in the transverse direction, over at least one of said predefined edge positions of said at least one web of film wound around the core, the laser rangefinder being configured to detect any edge misalignment in the transverse direction. equal to or greater than said displaced distance, with respect to the predefined edge position, of the lateral edges of the film strip wound on the roller.

A laser rangefinder is a device that includes a laser emitter and a laser receiver adjacent to each other configured to emit a narrow laser beam through the laser emitter and to detect, by means of the laser receiver, a light reflected from said laser beam that impacts against an object oriented toward the laser emitter. The time of flight of light between the emission of the laser beam and the detection of the reflected light allows a precise measurement of the distance between the laser emitter and the object that interrupts the laser beam.

The laser rangefinder is configured to emit a laser beam in a plane perpendicular to the at least one rewind shaft, in a plane perpendicular to the transverse direction, and directed towards the at least one rewind shaft, that is, the beam is emitted laser preferably against the at least one rewinding shaft or adjacent to said at least one rewinding shaft, preferably perpendicular thereto.

The laser rangefinder is also configured to be located, in the transverse direction, in a measurement position where said plane, through which the laser beam is emitted, is located at a displaced distance, in the transverse direction, with respect to the plane that contains a side edge of the film strip located at the predefined edge position. The laser beam, emitted at said measuring position, is parallel to a side surface of a roller formed on the at least one rewind shaft, the side surface being oriented towards said laser beam, and the laser beam being spaced from said side surface. the distance moved. Any deviation, equal to or greater than the offset distance, of the side edge of the film web wound on the roller from the predefined side edge position will interfere with the laser beam, producing edge misalignment detection.

Additionally, the laser rangefinder can detect the distance between the laser emitter and the side edge that causes such disruption and, therefore, can detect which portion of the roller includes the side edge misalignment.

According to a second aspect, the present invention is directed to a film rewinding operating method of a film rewinding machine. In a known manner, the procedure comprises:

• transporting at least one tensioned web of film of a flexible sheet material in a transport direction along a transport path while maintaining two opposite side edges of said film web in predefined edge positions in a transverse direction perpendicular to the direction Of transport;

• winding each of said at least one strip of film around a core that forms a roller.

The present invention also proposes, in a manner not known in the state of the art, the following steps:

• analyze at least one side edge of the at least one film web using at least one laser rangefinder to detect any edge misalignment in the transverse direction equal to or greater than a given offset distance, with respect to the predefined edge position, of the side edges of the film web wound on the roller; and

• associating operating parameters of the machine during winding of said at least one film web with information provided by the at least one laser rangefinder and using said information and associated operating parameters to at least automatically regulate the operating parameters of subsequent film winding operations. said machine to reduce or avoid said edge misalignments.

Accordingly, the proposed method, which can be applied to a machine such as the machine described above, includes a first step for detecting an edge misalignment using at least one laser rangefinder.

Subsequently, the information obtained by said laser rangefinder is associated with the operating parameters existing in the machine during the winding of the film web. Using a closed-loop analysis of machine operating parameters and edge misalignments detected by the laser rangefinder, operating parameters can be modified to prevent or reduce the presence of edge misalignments in future winding operations.

The analysis of the at least one lateral edge can be carried out by projecting at least one laser beam towards the at least one rewind shaft in a plane perpendicular to the at least one rewind shaft, said plane being at a displaced distance, in the direction transversal, over the predefined edge position and measuring the time of flight of said laser beam.

Other features of the invention emerge from the following detailed description of an embodiment.

Brief description of the figures

From the following detailed description of an embodiment the above and other advantages and features will be more fully understood with reference to the accompanying drawings, which are to be taken in an illustrative and non-limiting manner, in which:

Fig. 1A shows a schematic perspective view of the proposed film rewinder according to a first embodiment in which the film web is divided between upper and lower film webs that are wound around an upper rewinding shaft and a shaft. lower rewinding shaft formed by upper rollers and lower rollers, and in which the upper laser rangefinders emit laser beams towards the upper rewinding shaft and the lower laser rangefinders emit laser beams towards the lower rewinding shaft, the upper laser rangefinders being supported and the lower laser rangefinders on the same carts;

Fig. 1B shows an embodiment similar to that shown in Fig. 1A, in which the upper laser rangefinders are supported on upper carriages and the lower laser rangefinders are supported on lower carriages;

Figures 2A and 2B show an embodiment similar to that shown in Figures 1A and 1B, in which the same laser rangefinders emit laser beams towards the upper rewind shaft, as shown in Fig. 2A and, subsequently, the same Laser rangefinders are set to emit laser beams toward the lower rewind shaft, as shown in Fig. 2B;

Figures 3A and 3B show an embodiment similar to that shown in Figures 1A and 1B, in which a single laser rangefinder is automatically actuated to move along said transverse guide in the transverse direction and to stop by placing the al at least one laser rangefinder over different measuring positions for measuring misalignments of different side edges of the film webs wound on the rollers;

Figures 4A and 4B show a schematic cross section of the film rewinder shown in any of the preceding claims, wherein Fig. 4a shows upper and lower rollers formed on the upper and lower rewinding shafts located in the rewinding position, and Fig. 4B shows a later stage when said rollers have been moved to the extraction position and new empty cores are placed in the rewinding position, reversing the positions of the upper first and second rewinding shafts and the lower rewinding shafts. first and second rewind.

Detailed description of an embodiment

From the following detailed description of an embodiment the above and other advantages and features will be more fully understood with reference to the accompanying drawings, which are to be taken in an illustrative and non-limiting manner.

The proposed misalignment detector film rewinding machine includes a film feeder (not shown) that transports a film web 1 of a flexible sheet material in a transport direction CD along a transport route 3 towards a rewinding station 10.

Said film feeder also includes an automatic film tensioning device to maintain the film web 1 at a constant tension during its transport, avoiding variations in the tension of the film web 1, which could produce elastic elongation of the web. 1 film, causing a reduction in width. This automatic film tensioning device is well known in the state of the art and many different approaches are possible which usually include very precise control of the rotation speeds of several cylinders on which the film web 1 is supported along of transport route 3.

The film feeder is also configured to maintain the two opposite side edges E of the film web 1 at predefined edge positions in the transverse direction TD. Said transverse direction Td is a direction perpendicular to the transport direction CD. This can be achieved, for example, by using an optical detector to determine the precise position of the lateral edge E of the film web 1.

The rewinding station 10 is fed with the film web 1 from the film feeder and rewinds said film web 1 around at least one core supported on a rewind shaft 11a, 11b perpendicular to the transport direction CD.

The machine further comprises at least one laser rangefinder 20 configured to project a laser beam towards the rewinding shaft 11a, 11b, in a plane perpendicular to the rewinding shaft 11a, 11b.

Said laser rangefinder 20 is located in a measurement position at a displaced distance from the film edge, so that a misalignment of said film edge equal to or greater than said displaced distance will interrupt the laser beam, producing its detection.

According to one embodiment, the at least one laser rangefinder 20 are two laser rangefinders 20 configured to project parallel laser beams spaced a distance, in the transverse direction TD, equal to the distance between the two opposite edges of the film web 1 in the transverse direction TD. transverse TD plus twice the displaced distance to detect any edge misalignment simultaneously on both side surfaces of the same roller 4.

It is also proposed to transport several film webs through said transport path 3. In this case, each film strip 1 will be wound around an independent core supported on the at least one rewinding shaft 11a, 11b, defining a roller 4.

The machine may comprise a carriage 21, which supports said at least one laser rangefinder 20, slidably fixed to a transverse guide and automatically driven to move along said transverse guide in the transverse direction TD and to stop by positioning the at least a laser rangefinder 20 over at least one of said measuring positions to measure misalignments of different side edges E of the film webs 1 wound on the rollers. For example, Figures 3A and 3B show different stopping positions of the same laser rangefinder 20 on the same machine. In this way, a single laser rangefinder 20 can analyze all the side edges of all the rolled rollers simultaneously on the same axis.

Furthermore, if the at least one laser rangefinder 20, or a mirror affecting the laser beam emitted by the at least one laser rangefinder 20, is pivotally mounted about an axis parallel to the at least one rewind shaft 11a, 11b and is automatically driven to alternately direct the laser beam toward the at least one upper rewinding shaft 11a and toward the at least one lower rewinding shaft 11b, a single laser rangefinder 20 can analyze all side edges of all wound rollers. simultaneously on several axes.

If such an analysis is carried out during the final moments of the winding process before the roll is completed, this analysis can be carried out simultaneously with the winding process, without affecting the productivity of the machine.

Said carriage 21 can support one or more laser rangefinders 20, for example, two laser rangefinders 20 that emit parallel laser beams as described above. The carriage 21 is automatically driven to move in the transverse direction TD along the transverse guide, to place the laser rangefinders 20 in different measuring positions to detect misalignments on different side surfaces of the same roller 4 or different rollers.

According to a further embodiment of the present invention, the at least one rewinding shaft 11a, 11b includes at least one upper rewinding shaft 11a and at least one lower rewinding shaft 11b parallel to each other, where the transport path 3 is divided between an upper transport path 3a, which transports one or more upper film webs 1a, connected to the at least one upper rewinding shaft 11a and a lower transport path 3b, which transports one or more lower film webs 1b, connected with at least one lower rewind shaft 11b.

The at least one upper rewinding shaft 11a supports a core for each upper strip of film 1a, which is wound around said core defining an upper roller. The at least one lower rewinding shaft 11b supports a core for each lower strip of film 1b, which is wound around said core defining a lower roller. The at least one upper film strip 1a and the at least one lower film strip 1b are alternating film strips 1 so that the upper film strips 1a forming the upper rollers are separated, in the transverse direction TD, by an equal distance to the width of the lower film strips 1b, and the lower film strips 1b are separated, in the transverse direction TD, by a distance equal to the width of the upper film strips 1a.

The at least one laser rangefinder 20 includes at least one upper laser rangefinder 20a, directed towards the at least one upper rewind shaft 11a and configured to detect any edge misalignment of the side edges E of the upper webs 1a of film wound on the upper rollers, and at least one lower laser rangefinder 20b, directed towards the at least one lower rewinding shaft 11b to detect any edge misalignment of the side edges E of the lower film webs 1b wound on the lower rollers. According to this, the at least one upper laser rangefinder 20a is responsible for detecting edge misalignments affecting the at least one upper film band 1a, and the at least one lower laser rangefinder 20b is responsible for detecting edge misalignments affecting the at least one lower band 1b of film.

As described above, the upper laser rangefinder 20a may include two upper laser rangefinders 20a spaced apart, in the transverse direction TD, and emit parallel laser beams, and the lower laser rangefinder 20b may include two lower laser rangefinders 20b spaced apart. , in the transverse direction TD, and emit parallel laser beams.

Alternatively, the at least one laser rangefinder 20 or a mirror affecting the laser beam emitted by the at least one laser rangefinder 20, is pivotally mounted about an axis parallel to the at least one rewind shaft 11a, 11b. and is automatically actuated to alternately direct the laser beam towards the at least one upper rewinding shaft 11a and towards the at least one lower rewinding shaft 11b.

Said at least one laser rangefinder 20 may also be two laser rangefinders 20 that emit parallel laser beams.

According to another embodiment, the carriage 21 supports the at least one upper laser rangefinder 20a and the at least one lower laser rangefinder 20b. Alternatively, the carriage 21 includes an upper carriage 21a that supports the at least one upper laser rangefinder 20a and a lower carriage 21b that supports the at least one lower laser rangefinder 20b, said upper carriage 21a and said lower carriage 21b being driven by independently allowing independent detection of lateral misalignments of the upper film bands 1a and the lower film bands 1b.

The at least one rewinding shaft 11a, 11b can be removable between a roller winding position, where at least a part of the film web 1 is attached around the core, and a roller extraction position where a finished roller of the film web 1 transported through the transport path 3 and is removed from the rewinding shaft, for example, by a free end of said shaft. The at least one laser rangefinder 20 may be configured to emit the laser beam preferably towards the at least one rewind shaft 11a, 11b when located in the roller winding position, allowing detection to be carried out simultaneously with winding, increasing productivity, but alternatively said laser beam can be emitted towards the at least one rewinding shaft when it is located in the roller extraction position.

The at least one rewinding shaft 11a, 11b may also include a first rewinding shaft 11a, 11b and a second rewinding shaft 11a', 11b', parallel to each other and with interchangeable positions between the roller winding position and the position roller extraction.

When the machine includes at least one upper rewinding shaft 11a, it may be removable between an upper roller winding position, where a part of the upper film web 1a is attached around the core, and an upper roller extraction position. where a finished upper roller is decoupled from the upper web 1a of film transported through the upper transport path 3a and is extracted from the at least one upper rewinding shaft 11a.

For example, the first and second rewinding shafts 11a, 11a', the first and second upper rewinding shafts 11a, 11a', or the first and second lower rewinding shafts 11b, 11b' may be cantilever supported in a rewinding mechanism. rotation with a center of rotation located between both rewinding shafts, allowing the exchange of their positions by rotating around said center of rotation. Once their positions have been exchanged, the rollers recently located in the extraction position are decoupled from the respective upper or lower film band 3a, 3b, connecting said upper or lower film band 3a, 3b with respective new empty cores supported on the rewinding shaft newly positioned in the winding position, allowing uniform winding, and allowing the removal of the newly formed rolls from the rewinding shaft located in the pulling position while forming new rolls.

The at least one laser rangefinder 20 may be configured to emit the laser beam towards the at least one upper rewind shaft 11a when it is located in the upper roller winding position or when it is located in the upper roller extraction position.

Similarly, the at least one lower rewinding shaft 11b may be movable between a lower roller winding position, where part of the lower film web 1b is attached around the core, and a lower roller removal position where A finished lower roller is decoupled from the lower film web 1b transported through the lower transport path 3b and is removed from the at least one lower rewinding shaft. In this case, the at least one laser rangefinder 20 is configured to emit the laser beam towards the at least one lower rewinding shaft 11b when it is located in the winding position of the lower roller or when it is located in the extraction position of the roller. lower.

The at least one upper rewinding shaft 11a may include a first upper rewinding shaft 11a and a second upper rewinding shaft 11a', parallel to each other and with interchangeable positions between the upper roller winding position and the roller extraction position. upper, and the at least one lower rewinding shaft 11b includes a first lower rewinding shaft 11b and a second lower rewinding shaft 11b', parallel to each other and with interchangeable positions between the winding position of the lower roller and the extraction position of the lower roller.

According to a further embodiment, the at least one laser rangefinder 20 is connected to a control device configured to monitor operating parameters of the machine and configured to operate adjustment devices included in the machine to modify said operating parameters in response to measurements obtained from said laser rangefinder 20.

The operating parameters may include the constituent material of the film web, the transport speed, or parameters indicative thereof, the tension of the film web 1 or parameters indicative thereof, the torque of the at least one shaft 11a, 11b of rewinding and/or feeding shafts, the compression of the film strip in a contact line between two feeding shafts or parameters indicative thereof, among others, and the adjustment devices may include several motors driving the rewinding shafts and/or the feeding shafts, adjustment motors that drive a movement of one feeding shaft against another feeding shaft to regulate the compression force in the contact line between them.

Preferably, the predefined edge positions of the at least one film web 1 are defined by multiple blades, integrated in a cutting station, which interfere with the transport path 3 to cut a film material, wider than the web 1. of film and transported through said transport path 3, on one or more film strips 1. This type of machine is known as a cutting machine.

The cutting station may be integrated into the film feeder, and film material may be fed into the film feeder from a feed roller that is unwound to feed the film into the transport path 3.

The present invention is also directed to a film rewinding operating method of a film rewinding machine. First, at least one tensioned film web 1 of a flexible sheet material is transported in a transport direction CD along a transport path 3, maintaining two opposite side edges E of said film web 1 in predefined positions. of edge in a transverse direction TD perpendicular to the transport direction CD. Then, each of said at least one film strip 1 is wound around a core that forms a roller.

The method then further includes analyzing at least one side edge E of at least one film web 1 using at least one laser rangefinder 20 to detect any edge misalignment in the transverse direction equal to or greater than a given offset distance, with respect to the predefined edge position, of the side edges E of the film web 1 wound on the roller.

Then, the operating parameters of the machine during winding of said at least one film web 1 are associated with information provided by the at least one laser rangefinder 20 and use said information and associated operating parameters to at least automatically adjust the operating parameters of subsequent winding operations of said machine to reduce or avoid said edge misalignments.

Accordingly, the proposed method, which can be applied to a machine such as the machine described above, includes a first step for detecting an edge misalignment using at least one laser rangefinder 20.

Subsequently, the information obtained by said laser rangefinder 20 is associated with the operating parameters existing in the machine during the winding of the film band 1. Using a closed loop analysis of the machine operating parameters and the edge misalignments detected by the laser rangefinder 20, the operating parameters can be modified to prevent or reduce the presence of edge misalignments in future winding operations.

The method may further comprise automatically comparing machine operating parameters when edge misalignments are detected and when edge misalignments are not detected to determine the automatic adjustments required to reduce or avoid said edge misalignments.

The at least one laser rangefinder 20 will preferably be used to detect edge misalignments on the roller while winding of the film web 1 on the roller is carried out.

Multiple side edges E of the at least one film strip 1 can be analyzed successively by the same laser rangefinder 20, by moving the laser rangefinder 20 from one measurement position to another measurement position.

When the at least one winding shaft is removable between the roller winding position and the roller extraction position, edge misalignments can be measured by directing the laser beam towards the at least one winding shaft located in the winding position. of the roller. In this case, the laser beams will be redirected towards the at least one winding shaft located in the roller extraction position to allow its use as a visual reference.

Such reorientation of the laser beam can be achieved by tilting the laser rangefinder 20 or tilting a mirror that affects the laser beam.

Alternatively, the detection of edge misalignments and visual reference can both be carried out on the at least one winding shaft while it is located in the roller extraction position.

Claims (15)

1. A film rewinding machine comprising a misalignment detector and further comprising: a film feeder configured to provide at least one web (1) of tensioned film of a flexible sheet material transported in a transport direction (CD) along a transport path (3) and to maintain two side edges (E ) of said film web (1) at predefined edge positions in a transverse direction (TD) perpendicular to the transport direction (CD), the film feeder including an automatic film tensioning device to maintain the web (1) of film with a constant tension during transport; a rewinding station (10), connected to the transport path (3) for receiving said at least one web (1) of tensioned film, the rewinding station (10) including at least one rewinding shaft (11a, 11b). with an axis parallel to the transverse direction (TD) and configured to support and rotate at least one core to wind said at least one band (1) of film around the core that forms a roller (4); characterized in that the misalignment detector comprises: at least one laser rangefinder (20) configured to be placed in a measuring position and to project a laser beam directed towards the at least one rewind shaft (11a, 11b) in a plane perpendicular to the at least one rewind shaft when is in said measuring position, said plane being at a distance displaced in the transverse direction, on at least one of said predefined edge positions of said at least one strip of film wound around the core, the laser rangefinder (20) being configured ) to detect any edge misalignment in the transverse direction (TD) equal to or greater than said displaced distance, with respect to the predefined edge position, of the side edges (E) of the film web wound on the roller. 2. The film rewinding machine according to claim 1, wherein the at least one laser rangefinder is configured to emit the laser beam against the at least one rewinding shaft. 3. The film rewinding machine according to claim 1 or 2, wherein the at least one laser rangefinder is two laser rangefinders configured to project parallel laser beams spaced a distance apart, in the transverse direction, equal to the distance between the two. opposite edges of the film web in the transverse direction plus two times the displaced distance to detect any edge misalignment simultaneously at both side edges of the film web. 4. The film rewinding machine according to claim 1, 2 or 3, wherein the film web feeder transports several film webs through said transport path; wherein each film web is wound around an independent core supported on the at least one rewind shaft defining a roller; and in which The machine further comprises a carriage (21), which supports said at least one laser rangefinder, slidably fixed to a transverse guide and automatically driven to move along said transverse guide in the transverse direction and to stop by placing the at least one laser rangefinder over at least one of said measuring positions for measuring misalignments of different side edges of the film webs wound on the rollers. 5. The film rewinding machine according to any preceding claim wherein The at least one rewinding shaft (11a, 11b) includes at least one upper rewinding shaft (11a) and at least one lower rewinding shaft (11b) parallel to each other, where the transport path (3) is divided between an upper transport path (3a), which transports at least one upper strip (1a) of film, connected to the at least one upper rewinding shaft (11a) and a lower transport path (3b), which transports at least one lower film band (1b), connected to at least one lower rewinding shaft (11b); in which the at least one upper rewinding shaft (11a) supports a core for winding each upper web (1a) of film defining an upper roller and the at least one lower rewinding shaft (11b) supports a core for winding each lower web (1a). 1b) of film defining a lower roller, the at least one upper band (1a) of film and the at least one lower band (1b) of film being alternating bands of film; and in which The at least one laser rangefinder (20) includes at least one upper laser rangefinder (20a), directed towards the at least one upper rewind shaft (11a) configured to detect any edge misalignment of the side edges (E) of the bands upper rollers (1a) of film wound on the upper rollers, and at least one lower laser rangefinder (20b), directed towards the at least one lower rewinding shaft (11b) to detect any edge misalignment of the side edges (E) of the lower webs (1b) of film wound on the lower rollers, or the at least one laser rangefinder (20) or a mirror that affects the laser beam emitted by the at least one laser rangefinder (20) is pivotally mounted around a parallel axis on the at least one shaft (11a, 11b) of rewinding and is automatically actuated to alternately direct the laser beam towards the at least one upper rewinding shaft (11a) and towards the at least one lower rewinding shaft (11b). 6. The film rewinding machine according to claim 5, when dependent on claim 4, wherein the carriage supports the at least one upper laser rangefinder and the at least one lower laser rangefinder; either The carriage (21) includes an upper carriage (21a) that supports the at least one upper laser rangefinder (20a) and a lower carriage (21b) that supports the at least one lower laser rangefinder (20b), said upper carriage (21a) ) and lower carriage (21b) driven independently. 7. The film rewinding machine according to any preceding claim wherein the at least one rewinding shaft (11a, 11b) is removable between a roller winding position, where a part of the film web is attached around the core, and a roller extraction position, where a finished roller is decoupled from the film web (1) transported through the transport path (3) and is extracted from the rewinding shaft (11a, 11b), and in the that the at least one laser rangefinder (20) is configured to emit the laser beam towards the at least one rewind shaft (11a, 11b) when it is placed in the roller winding position or when it is placed in the roller extraction position. roller; or in which The at least one upper rewinding shaft (11a) is removable between an upper roller winding position, where a part of the upper film web is attached around the core, and an upper roller extraction position, where it is disengaged an upper finished roller of the upper web (1a) of film transported through the upper transport path (3a) and is extracted from at least one upper rewinding shaft (11a), and in which the at least one laser rangefinder ( 20) is configured to emit the laser beam towards the at least one upper rewinding shaft (11a) when it is placed in the upper roller winding position or when it is placed in the upper roller extraction position, and the at least one Lower rewind shaft (11b) is movable between a lower roller winding position, where a part of the lower film web (1b) is attached around the core, and a lower roller extraction position, where a finished lower roller of the lower web (1b) of film transported through the lower transport path (3b) and is extracted from the at least one lower rewinding shaft (11b), and in which the at least one laser rangefinder (20 ) is configured to emit the laser beam towards the at least one lower rewinding shaft (11b) when it is placed in the lower roller winding position or when it is placed in the lower roller extraction position. 8. The film rewinding machine according to claim 7, wherein The at least one rewinding shaft includes a first rewinding shaft (11a, 11b) and a second rewinding shaft (11a', 11b'), parallel to each other and with interchangeable positions between the roller winding position and the roller winding position. roller extraction; or in which The at least one upper rewinding shaft (11a) includes a first upper rewinding shaft (11a) and a second rewinding shaft (11a'), parallel to each other and with interchangeable positions between the upper roller winding position and the upper roller winding position. upper roller extraction and the at least one lower rewinding shaft (11b) includes a first lower rewinding shaft (11b) and a second rewinding shaft (11b'), parallel to each other and with interchangeable positions between the winding position of lower roller and lower roller extraction position. 9. The film rewinding machine according to any preceding claim wherein the at least one laser rangefinder is connected to a control device configured to monitor operating parameters of the machine and configured to operate adjustment devices included in the machine to modify said operating parameters in response to measurements obtained from said laser rangefinder. 10. The film rewinding machine according to any preceding claim wherein the predefined edge positions of the at least one film web are defined by multiple blades, integrated in a cutting station, which interfere with the transport path for cutting. a film material, wider than the film web and transported through said transport path, in one or more film webs. 11. A misalignment detection procedure for a film rewinding machine, the procedure comprising: transport at least one tensioned band (1) of film of a flexible sheet material in a transport direction (CD) along a transport path (CP) maintaining two opposite lateral edges (E) of said band (1) of film at predefined edge positions in a transverse direction (TD) perpendicular to the transport direction (CD); winding each of said at least one strip (1) of film around a core that forms a roller; characterized in that the procedure also includes: analyze at least one side edge (E) of the at least one film strip (1) using at least one laser rangefinder (20) to detect any edge misalignment in the transverse direction (TD) equal to or greater than a displacement distance given, with respect to the predefined edge position, of the side edges (E) of the film web (1) wound on the roller; and associate operating parameters of the machine during winding of said at least one web (1) of film with information provided by the at least one laser rangefinder (20) and use said information and associated operating parameters to at least automatically regulate the operating parameters of subsequent winding operations of said machine to reduce or avoid said edge misalignments. 12. The misalignment detection method according to claim 11, wherein the analysis of the at least one side edge (E) is carried out by projecting at least one laser beam towards the at least one rewind shaft (11a, 11b). in a plane perpendicular to at least one rewinding shaft, said plane being at a displaced distance, in the transverse direction (TD), about the predefined edge position and measuring the time of flight of said laser beam. 13. The misalignment detection method according to claim 11 or 12, wherein the method further comprises automatically comparing the operating parameters of the machine when edge misalignments are detected and when edge misalignments are not detected to determine automatic adjustments required to reduce or avoid such edge misalignments. 14. The misalignment detection method according to claim 11, 12 or 13, wherein the at least one laser rangefinder (20) is used to detect edge misalignments in the roller while winding of the belt is carried out ( 1) film on the roller. 15. The misalignment detection method according to claim 11, 12, 13 or 14, wherein multiple side edges of the at least one film web are successively analyzed by the same laser rangefinder (20).