CONTAINER LABELING MACHINE
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- P E LABELLERS SPA
- Filing Date
- 2023-03-28
- Publication Date
- 2026-05-19
Smart Images
Figure MX434223B1
Abstract
Description
CONTAINER LABELING MACHINE DESCRIPTIVE MEMORANDUM The present invention relates to a container labeling machine and, specifically, to a labeling machine of the type known as roll-fed. As is known, machines for labeling containers in general, and bottles in particular, are widely used and have a conveyor belt to transport bottles along a forward path that is normally made up of a peripherally arranged rotating carousel with a plurality of supports for the individual bottles and which are suitable for rotating the bottles on their own axis. In addition, the labeling machines have, along a bottle feed path, at least one labeling unit equipped with a transfer drum that allows a respective label to be applied to each bottle that appears progressively in front of the transfer drum. Specifically, roll-fed labeling machines are known for producing labels by cutting a continuous strip of labels on which multiple labels are printed in succession and which are wound on a reel. More specifically, these types of labeling machines are equipped with an unwinding unit that allows the label strip to be taken from the reel and fed to a cutting drum, which cuts the label strip between each label, releasing the individual labels. Once separated after cutting, they are transferred to the drum, which guides the labels to adhere to the respective bottles transported by the carousel. It should be mentioned that the label tape has adhesive strips pre-applied to the face of the individual labels that is designed to make contact with the bottles, or they may not have adhesive and, in this case, a glue spreader roller facing the transfer drum laterally applies, respectively, to the front and back edges of the labels, two strips of glue before the labels are transferred to the bottles. Traditional machines are normally structured so that the label strip is cut by interference by passing the label strip through an intermediate space formed between two labels, one of which can be moved and fixed integrally in rotation with the cutting drum, while the other is stationary, fixed to the machine's support structure and oriented towards the side surface of the cutting drum. This method, in traditional machines, involves the presence of specialized personnel for the precise adjustment of the position of the fixed blade and one or more moving blades associated with the cutting drum to ensure the correct intermediate space between the blades that cut the label strip. Furthermore, this method also requires that the cutting drum, during its rotation, perform a movement that is as regular and precise as possible. Normally, and for this purpose, in known traditional machines, the cutting drum is rotatably supported by a considerably large structure, known as a support, which is provided as an individual metal casting. Typically, this structure has two bushing-shaped portions that are mutually and axially separated along the axis of the cutting drum and form respective rotation seats, where the opposite ends of the cutting drum support rod are coupled by virtue of bearings filled with pre-charged oil, again, to ensure the regularity of the rotary motion of the cutting drum. In turn, the two bushing-shaped portions are mutually connected by two elongated connecting arms that are mutually and diametrically opposed with respect to the axis of the cutting drum, oriented towards the lateral surface of the cutting drum and are extended substantially parallel to the axis of the cutting drum. The structure that supports the cutting drum also performs the important function of rigidly supporting, on one of the two elongated arms, the fixed blade by means of an adapted support body, which allows its adjustment in position with respect to the movable blade that is fixed to the cutting drum. The need for such support in traditional roll-fed machines implies a certain complexity of construction. In addition, traditional roll-fed machines have considerable maintenance problems and significant difficulty in blade replacement operations. Another drawback observed in traditional roll-fed machines arises from the structural complexity of the cutting drum structured in this way and its limited versatility, because it is provided with a fixed number of divisions and a non-variable diameter, which limits the variety of label lengths that can be processed by the labeling machine. The objective of the present invention is to provide a labeling machine that is capable of improving the prior art in one or more of the aspects indicated above. Within this objective, one object of the invention is to provide a labeling machine that is capable of ensuring the correct execution of the cutting of the label strip under any operating condition. Another object of the invention is to provide a labeling machine that is capable of providing the highest guarantees of efficiency in the operation of the cutting drum. Another object of the invention is to provide a labeling machine that allows easy replacement of the blades that cut the label strip, even by non-specialized operators. Another object of the invention is to provide a labeling machine that allows increasing the variety of label lengths that can be processed. Another object of the present invention is to provide a solution that can also be used in existing roll-fed machines to offer the possibility of easily conditioning them. Another object of the present invention is to overcome the drawbacks of the prior art in a way that is an alternative to existing solutions. No less important is an object of the invention to provide a labeling machine that is highly reliable, relatively easy to provide, and easy to manufacture at low cost. This objective, as well as these and other objectives that will become more evident hereafter, are achieved by means of a labeling machine according to claim 1, optionally provided with one or more of the features of the dependent claims. Other features and advantages of the invention will become more evident from the description of a preferred but not exclusive embodiment of the labeling machine according to the invention, illustrated by way of non-limiting example in the accompanying drawings, where: Figure 1 is a schematic top plan view of the labeling machine according to the invention; Figure 2 is a perspective view of a cutting drum of the machine according to the invention; Figure 3 is a schematic cross-sectional view, taken along a diametric plane, of the cutting drum of the machine according to the invention; Figure 4 is an enlarged scale view of a detail of the cutting drum of the machine according to the invention, shown in cross-section along a plane that is perpendicular to the axis of the cutting drum; Figure 5 is a cross-sectional view, taken along a diametric plane, of the cutting drum of the machine according to the invention; Figure 6 is a top plan view of a vacuum distribution unit associated with the cutting drum of the machine according to the invention; Figure 7 is a sectional view, taken along plane VII-VII of the figure QbQQnn / QZnZ / B / YIAI 6; Figure 8 is a front elevation view of the cutting drum of the machine according to the invention; Figure 9 is a partial cross-sectional view of the cutting drum, taken along plane IX-IX of Figure 8; Figure 10 is a cross-sectional view of the cutting drum of the machine according to the invention, taken along a diametric plane that is different from that in Figure 5 and with parts omitted for simplicity; Figure 11 is a top plan view of a box-type blade support body of a cutting drum machine cutting device according to the invention; Figure 12 is a cross-sectional view, taken along plane XII-XII of Figure ii; Figure 13 is an exploded perspective view of the box-type blade support body; Figure 14 is a perspective view of elements that make up the cutting drum of the machine according to the invention. With reference to the figures, the labeling machine according to the invention, generally designated by reference number 1, comprises a conveyor belt 2 for the containers 3 to be labeled along a forward path 2a, which is conveniently constituted by a rotating carousel peripherally provided with plates 4 that can rotate and are designed so that each one supports a respective container 3. At least one labeling unit 5 exists along the forward path 2a, which comprises an unwinding unit 6 that may consist, for example, of a pair of traction rollers 6a, 6b and is designed to pick up a strip of labels 7 from a reel, on which the labels 8 to be applied to the containers 3 are continuously printed. The unwinding unit 6 feeds the label strip 7 to a cutting drum 9, which can rotate about its own axis 9a and is provided, on its side surface, with suction openings 10 to retain the label strip 7 in adhesion to its own side surface. Furthermore, the cutting drum 9 is provided with cutting means that allow the label strip 7 to be cut in the separation region between two consecutive labels 8 and is adapted to release the labels 8, obtained after being cut, to a transfer drum 11, which can rotate around its own axis, which, in turn, is designed to transfer the individual labels 8, received from the cutting drum 9, into contact with a respective container 3 coming from the conveyor belt 2. QbQQnn / QZnZ / B / YIAI Advantageously, the transfer drum 11 is circumferentially divided into sectors, each of which is designed to receive in adhesion an individual label 8 from the cutting drum 9. If the label strip 7 is not provided with pre-applied adhesive, there is conveniently an adhesive roller 12 located laterally to the transfer drum 11, which is designed to apply at least one strip of adhesive to each end of the labels 8. For this purpose, in the regions of each of the sectors of the transfer drum 11 on which the ends of the labels 8 are designed to rest, there are respective sliders 13 which are arranged in relief on the lateral surface of the transfer drum 11 with respect to the remaining part of the corresponding sector so that, after passing through the adhesive roller 12, the latter can apply a strip of adhesive to the labels 8. According to the invention, the cutting drum 9 supports at least one cutting device 14, which has an air suction chamber 15, which is substantially open on the lateral surface of the cutting drum 9 and within which at least one blade 16 is received, conveniently arranged so that its plane of arrangement is substantially parallel to a diametric plane of the cutting drum 9. Specifically, the suction chamber 15 can be connected to air suction means 17 to generate a force capable of attracting the label strip 7 against the blade 16, thereby cutting it to obtain the labels 8. Advantageously, the cutting drum 9 has, for each cutting device 14, at least an auxiliary region 18 to retain the label strip 7 in contact with the cutting drum 9, which is provided with auxiliary suction holes 19 and is arranged directly in front of the respective cutting device 14 with respect to the direction of rotation of the cutting drum 9. Specifically, the auxiliary retention region 18 can be connected to the suction means 17 before the connection of the suction chamber 15 of the respective cutting device 14 with the suction means 17 to produce, together with the unwinding unit 6, the tension of the label strip 7 before it is cut by the corresponding cutting device 14. In this way and thanks to the auxiliary retention region 18, a greater force is ensured to attract the label strip 7 towards the cutting drum 9 with respect to the portions of it affected only by the suction openings 10 and, consequently, a greater effectiveness of the cutting in the part of the blade 16, even under conditions of a not perfect sharpening of said blade and especially at very high machine speeds. More specifically, the suction means 17 conveniently comprise a fixed vacuum distribution unit 20 on which the cutting drum 9 is rotatably mounted and in which there is a cutting region 21, which has a vacuum chamber 22 connected to means QbQQnn / QZnZ / B / YIAI vacuum generating 23, consisting, for example, of a vacuum pump or the like, conveniently by means of a first coupling connector 24a, and provided with a vacuum opening 25 that is formed on the face of the distribution unit 20 that is directed towards the cutting drum 9. In the cutting region 21 of the distribution unit 20 there is also an auxiliary vacuum chamber 26 which is also connected to the vacuum generating means 23, for example, by means of a second coupling connector 24b, and is provided with an auxiliary vacuum opening 27, again formed on the face of the distribution unit 20 which is directed towards the cutting drum 9 and angularly separated from the vacuum opening 25 with respect to the direction of rotation of the cutting drum 9. In turn, the suction chamber 15 of each cutting device 14 has, on the face of the cutting drum 9 that is directed towards the distribution unit 20, at least one communication opening 28, which is designed to be oriented towards the vacuum opening 25 during the rotation of the cutting drum 9, to establish a connection between the suction chamber 15 and the vacuum generating means 23, while the auxiliary retention region 18 comprises an auxiliary suction chamber 29 that communicates with the auxiliary suction ports 19 and with an auxiliary communication opening 30, which is also formed on the face of the cutting drum 9 that is directed towards the distribution unit and is designed, during the rotation of the cutting drum 9, to be oriented at least partially towards the auxiliary vacuum opening 27 to establish a connection between the auxiliary vacuum chamber 29 and the vacuum generating means 23 and, consequently,activate the auxiliary retention region 18 before the communication opening 28 of the suction chamber 15 of the corresponding cutting device 14 reaches the vacuum opening 25 and therefore before the cutting device 14 cuts the label strip 7. Advantageously, to ensure the correct tension of the label strip 7, there are automatic control means 31 which are constituted, for example, by an electronic controller, are functionally connected to the unwinding unit 6 and, in addition, are conveniently connected at the input to a detector of the angular position of the cutting drum 9 with respect to the support structure 5a of the labeling unit 5. Conveniently, the automatic control means 31 can be programmed to instruct the unwinding unit 6 to reduce the speed at which the unwinding unit 6 feeds the label strip 7 to the cutting drum 9 when the auxiliary communication opening 30 reaches the auxiliary vacuum opening 27 during the rotation of the cutting drum 9, so that as a consequence of the slowing of the supply speed of the label strip 7 in the unwinding unit 6 and the increased retention of the label strip 7 on the cutting drum 9, due to the activation of the auxiliary retention region 18, QbQenn / oznz / B / YiAi obtained by connecting the auxiliary suction chamber 29 to the vacuum generating medium 23, while the cutting drum 9 continues to rotate, a tension is produced in the label strip 7 between the unwinding unit 6 and the auxiliary retention region 18, which is greater than the tension produced by the dynamic friction generated by the sliding of the cutting drum 9 in the label strip 7. It should be mentioned that the auxiliary retention region 18 may consist of a block 32 forming the auxiliary suction chamber 29 with the corresponding auxiliary communication opening 30 and, on an outer face thereof, the auxiliary suction holes 9 and is received, preferably in a detachable manner, by the cutting drum 9 in a receiving notch 33, which is formed on the lateral surface of said cutting drum so that the outer face of the block 32 provided with the auxiliary suction holes 19 is aligned with the lateral surface of the cutting drum 9. Advantageously, the use of block 32 to provide the auxiliary retention region 18 allows, by varying the material from which block 32 is made, the provision of the auxiliary retention region 18 with a coefficient of friction, relative to the label strip 7, which is different from the coefficient of friction, again relative to the label strip 7, of the material from which the remaining part of the cutting drum 9 is made. Conveniently, both the vacuum opening 25 and the auxiliary vacuum opening TI have a substantially slot-type shape. Specifically, the vacuum opening 25 extends longitudinally along a direction that is substantially perpendicular to the rotation axis 9a of the cutting drum 9, whereas, conversely, the auxiliary vacuum opening 27 extends longitudinally along a circular arc around an axis that substantially coincides with the rotation axis 9a of the cutting drum 9. Advantageously, the auxiliary vacuum opening 27 is located at a greater distance from the rotation axis 9a of the cutting drum 9 with respect to the vacuum opening 25 so that the auxiliary communication opening 30, which is at a distance from the rotation axis 9a of the cutting drum 9 that corresponds substantially to the distance of the auxiliary vacuum opening 27, does not pass through the region of the vacuum opening 25 during the rotation of the cutting drum 9. Conveniently, the vacuum opening 25 and the communication opening 28 have substantially the same shape and size, whereas the auxiliary communication opening 30 may have the same transverse dimension and smaller dimensions in a longitudinal direction with respect to the auxiliary vacuum opening 27 and, optionally, a shape that may be different from that of the auxiliary vacuum opening 27, such as, for example, a circular shape. Advantageously, the cut-off region 21 is made up of at least a portion QfrQrnn / cznz / E / YiAi of the distribution unit 20 that is elastically loaded against the cutting drum 9, to obtain greater adhesion between the cutting region 21 and the cutting drum and to optimize the friction between the surfaces of the cutting drum 9 and the distribution unit 20. Specifically, and as can be seen in Figure 7, the cutting region 21 is provided in a separate body 34 with respect to the main body 35 of the distribution unit 20. Conveniently, the separate body 34 is mounted so that it can slide relative to the remaining part of the distribution unit 20 along a direction that is substantially parallel to the axis 9a of the cutting drum 9 and is held pushed towards the cutting drum 9 by elastic means. More specifically, the separate body 34 is provided with sliding coupling seats 36 for guide pins 37, which are fixed to the main body 35 of the distribution unit 20 and around which pusher springs 38 are mounted and interposed between the separate body 34 and the main body of the distribution unit 20. Advantageously, the distribution unit 20 is supported, as a whole, by ball-type clamps 60, which are distributed around an axis that substantially coincides with the axis 9a of the cutting drum 9, act on the support structure 5a and, thanks to the respective helical springs 61, allow the distribution unit 20 to be pressed against the cutting drum 9. Conveniently, in the distribution unit 20 there is also at least one first retaining slot 39a, which extends through at least one circular arc around an axis that is substantially parallel to the rotation axis 9a of the cutting drum 9 and is connected, by means of a third coupling connector 24c, to a vacuum generating means 23 and communicates with the suction openings 10 provided on the side surface of the cutting drum 9 to keep the label strip 7 and the labels 8, separated after cutting, in adhesion on the cutting drum 9. Optionally, in the body of the distribution unit 20, outside the cutting region 21, there may be a second retaining groove 39b, which extends along a circular arc having a larger diameter than the first retaining groove 39a, is substantially circumferentially aligned with the auxiliary vacuum opening 27, and allows a connection to be established between the vacuum generating means 23 and the auxiliary suction holes 19 of the auxiliary retaining region 18 to keep the auxiliary retaining region 18 active even after the latter has moved beyond the cutting region 21 during the rotation of the cutting drum 9 around its own axis 9a. Advantageously, and again in the distribution unit 20, in a position that is already angularly separated from the cutting region 21 with respect to the axis of rotation Qbaenn / Qznz / B / YiAi 9a of the cutting drum 9, there is a blowhole 40 that is connected to a pressurized air source, not shown, and is designed, during the rotation of the latter around axis 9a, to establish a connection with the suction openings 10, so that they emit a jet of air to allow the passage of the labels 8 obtained after cutting onto the transfer drum 11. Advantageously, and to facilitate the operation of setting up the machine in case of a change in the format of the labels 8 that must be transferred to the containers 3, and to provide the possibility of conditioning machines fed with existing rolls, by providing them with a system for cutting the labels 8, which is different from traditional interference cutting, the cutting drum 9 can be provided with at least two frames 42a and 42b that are fixed around a rotating drive frame 43, which in practice forms, with its axis, the rotation axis 9a of the cutting drum 9. Specifically, frames 42a, 42b are fixed to the drive rod 43 by means of detachable coupling means that extend substantially radially with respect to the axis of said drive rod. As shown in Figure 10, the detachable coupling means are advantageously constituted by screws 44, which are inserted into radial receiving seats 45 formed in housings 42a and 42b, have a transverse variation to form a splice region for the head 44a of the screws 44 and are coupled into radial female threads 46 provided on the outer side surface of the drive stem 43. Conveniently, the detachable coupling means further comprises centering pins 47 that project radially from the drive stem 43 and are designed to engage with coupling seats 48 formed in housings 42a and 42b. Advantageously, and as can be seen in Figure 5, the drive rod 43 passes axially through a central passage 49 formed in the distribution unit 20 and is conveniently supported, advantageously thanks to the interposition of bearings 50, by means of a bushing or collar element 51 which, in turn, is fixed to the machine support structure and, more specifically, to the support structure 5a of the labeling unit 5, by means of a flanged coupling 52. This method achieves a considerable simplification, with respect to the previous technique, of the machine parts designed to support the cutting drum 9, as well as a simplification of its mounting on the fixed parts of the machine. Furthermore, it should be mentioned that each cutting device 14 advantageously comprises a respective box-type blade support body 53, which defines the respective suction chamber 15 and is detachably received in a corresponding receiving seat 54 formed in the cutting drum 9. Conveniently and as specifically shown in Figure 4 and Figure 14, respective portions 54a, 54b of the receiving seat 54 of the box-type blade support body 53 of each cutting device 14 are formed in mutually facing regions of the frames 42a, 42b. Advantageously, the blade 16 of each cutting device 14 is detachably fixed to the box-type blade support body 53 by means of retaining pins 55, which are inserted through respective coupling openings 56, which are formed in the blade 16 and detachably couple to corresponding support seats 57, which are formed in the box-type blade support body 53 and can be accessed from the outside of the box-type blade support body 53 to allow the removal of the retaining pins 55 from the support seats 57. In this way, once the box-type blade support body 53 has been decoupled from the cutting drum 9, it is possible to remove the blade 16 from the box-type blade support body 53, after decoupled the retaining tabs 55 from the coupling openings 56 because they are pulled out of the support seats 57. Conveniently, on the outer surface of the box-type blade support body 53 there are, on mutually opposite sides, longitudinal grooves 58 that extend substantially parallel to the axis of rotation 9a of the cutting drum 9 and can be slidably coupled by respective ribs 59 formed in the inner walls by the receiving seat 54 of the box-type blade support body 53 and, more specifically, in the mutually oriented regions of the housings 42a, 52b where the portions 54a, 54b of the receiving seats 54 of the box-type blade support bodies 53 are formed. In this way, the coupling and uncoupling of the box-type blade support bodies 53 from the corresponding receiving seats 54 can occur by means of a relative sliding between the box-type blade support body 53 and the cutting drum 9, guided by the coupling of the ribs 59 along the grooves 58. It should be mentioned that the slots 58 are open at their end designed to be directed towards the distribution unit 20, while they are closed at the other end to block relative sliding between the box-type blade support body 53 and the cutting drum 9 in the direction of insertion of the box-type blade support body 53 into its own receiving seat 54 when the box-type support body 53 reaches the correct position with respect to the cutting drum 9. Advantageously, and to keep the retaining pins 55 in the respective support seats 57, when the box-type support body 53 is arranged in the corresponding receiving seat 54, the openings for accessing the support seats 57 from the outside The QbQQnn / QZnZ / B / YIAI retaining pins 54 are formed on the bottom of the grooves 58 so that they can be closed by the ribs 59. The operation of the container labeling machine according to the following is as follows. The unwinding unit 6 picks up the label strip 7 from the corresponding reel and, as is normal in traditional roll-fed machines, feeds it to the cutting drum 9 at the preset feed speed, which is less than the peripheral speed of the cutting drum 9 to compensate for any length difference that exists between the divisions of the cutting drum 9, formed by the space that is circumferentially present between the corresponding cutting devices and the length of the labels 7. Specifically, if the machine is operated at high speeds when, during the rotation of the cutting drum 9, the auxiliary communication opening 30 of the auxiliary retention region 18 directly preceding one of the cutting devices 14 reaches the auxiliary vacuum opening 27, the auxiliary retention region 18 is activated as a consequence of the connection of the auxiliary suction holes 19 with the generating means 23. Meanwhile, although the communication opening 28 of the suction chamber 15 of the cutting device 14 corresponding to the auxiliary retention region 18 that has been activated reaches the vacuum opening 25, its blade 16 is arranged in the separation region between two consecutive labels 8. At this point, the automatic control means 31 instructs the unwinding unit 6 to accelerate the feed speed of the label strip 7 to the cutting drum 9 by means of an increase in the rotation speed of the traction rollers 6a and 6b to bring the feed speed of the label strip 7 to a value that is closer to that of the peripheral speed of the cutting drum 9. At the same time, the communication opening 28 of the suction chamber 15 of the cutting device 14, which corresponds to the auxiliary retention region 18 that has been activated, reaches the vacuum opening 25, thus establishing a connection between the vacuum chamber 15 and the vacuum generating means 23 to attract the label strip 7 towards the suction chamber 15 and push it against the blade 16 to cut it. At the same time, the automatic control means 31 instructs the unwinding unit 6 to slow down the feed speed of the label strip 7 towards the cutting drum 9, so that while the cutting drum 9 continues its rotation around its own axis 9a at the same speed, with the label strip 7 held in the auxiliary holding region 18, tension is produced on the portion of the label strip 7 that is between the unwinding unit 6 and the auxiliary holding region 18, which facilitates the execution of a clean and regular cut of the label strip 7 by the blade 16. The automatic control means 31 then instructs the unwinding unit to feed the label strip to the cutting drum 9, returning the feed speed of the label strip 7 to the cutting drum 9 to its initial value, thus resynchronizing the label strip 7 with the cutting drum 9 while the label 8, which is separated after cutting, continues its movement while remaining adhered to the cutting drum 9. Alternatively, nothing prohibits, especially at low speeds, the feed speed of the label strip 7 from being maintained by the automatic control means 31, even during the cutting steps of the label strip 7, at a substantially constant value that is less than the value of the peripheral speed of the cutting drum 9, as is conventionally the case in traditional roll-fed machines. When the portion of the cutting drum 9 in which the label 8 is located, separated from the label strip 7, reaches the blow mold 40, the label 8 is released from the transfer drum 11, which first transfers it to the adhesive roller 12 so that two adhesive strips are applied to the ends of the labels 8, and then moves it to be attached to the respective container 3 transported by the conveyor belt 2. It has been discovered in practice that the invention achieves the intended objective and objects and, specifically, it is highlighted that the container labeling machine according to the invention allows changing the number of divisions of the cutting drum very easily depending on the format of the labels, something that is practically impossible to carry out in traditional roll-fed machines. Another advantage offered by the machine according to the invention with respect to traditional roll-fed machines is the ability to vary the diameter of the cutting drum as needed, without having to make structural modifications to the machine and without having to resort to highly qualified operators. The invention thus conceived is susceptible to various modifications and variations, all of which are within the scope of the attached claims; all details may also be replaced with other technically equivalent elements. In practice, the materials used, as long as they are compatible with the specific use, as well as the contingent shapes and dimensions, can be any in accordance with the requirements and the latest technology. The disclosures in the Italian patent application no. 102020000022882, from which this application claims priority, are incorporated herein as if inserted verbatim. Whenever technical features are mentioned in any claim, they are followed by reference numbers, and these reference numbers have been included with the sole Qbaenn / Qznz / B / YiAi purpose of increasing the comprehensibility of the claims and, consequently, said reference numbers have no limiting effect on the interpretation of each element identified by example by said reference numbers.
Claims
1. A labeling machine comprising a conveyor belt (2) for containers (3) to be labeled along a forward path (2a) and at least one labeling unit (5) arranged along said forward path (2a) of the containers (3), said at least one labeling unit (5) comprising an unwinding unit (6) adapted to pick up a label strip (7) from a reel, which has printed thereon a continuous series of labels (8) to be applied to the containers (3), and to feed said label strip (7) to a cutting drum (9) which is provided, on its lateral surface, with suction openings (10) for retaining said label strip (7) in adhesion to the lateral surface of said cutting drum (9), and provided with cutting means for cutting said label strip (7) in the region of separation between two consecutive labels (8),said cutting drum (9) is adapted to release the labels (8) obtained after cutting to a transfer drum (11) intended to transfer the individual labels (8) so that they can be affixed to a respective container (3) coming from said conveyor belt (2), characterized in that said cutting drum (9) supports at least one cutting device (14) provided with an air suction chamber (15) that is substantially open on the lateral surface of said cutting drum (9) and receives inside at least one blade (16), said suction chamber (15) can be connected to air suction means (17) to draw said strip of labels (7) against said blade (16), to cut said strip of labels (7).
2. The machine according to claim 1, further characterized in that said cutting drum (9) has, for each cutting device (14), at least an auxiliary region (18) for retaining said label strip (7) which is provided with auxiliary suction holes (19) and is arranged directly in front of the respective cutting device (14) with respect to the direction of rotation of said cutting drum (9), said auxiliary retention region (18) can be connected to said suction means (17), prior to the connection of the suction chamber (15) of the respective cutting device (14) to said suction means (17), to produce, in cooperation with said unwinding unit (6), the tension of said label strip (7).
3. The machine according to one or more of the preceding claims, further characterized in that said suction means (17) comprise a fixed vacuum distribution unit (20) on which said cutting drum (9) is rotatably mounted, a cutting region (21) is formed in said distribution unit (20) and has a vacuum chamber (22) connected to vacuum generating means (23) and provided with a vacuum opening (25) formed on the face of said distribution unit (20) facing the cutting drum (9), and an auxiliary vacuum chamber (26) connected to said vacuum generating means (23) and provided with an auxiliary vacuum opening (27) formed on the face of said distribution unit (20) facing the cutting drum (9), said suction chamber (15) having,On the face of said cutting drum (9) that is oriented towards said distribution unit (20), at least one communication opening (28) which is designed to face said vacuum opening (25), during the rotation of said cutting drum (9) to establish a connection between said suction chamber (15) and said vacuum generating means (23), said auxiliary retention region (18) comprises an auxiliary suction chamber (29) that communicates with said auxiliary suction orifices (19) and with an auxiliary communication opening (30) that communicates with said auxiliary suction orifices (19), to be oriented, at least partially, towards said auxiliary suction opening (27), before said communication opening (28) reaches said vacuum opening (25).
4. The machine according to one or more of the preceding claims, further characterized in that it comprises automatic control means (31) that are functionally connected to said unwinding unit (6) and are adapted to instruct a reduction of the speed at which said unwinding unit (6) supplies said label strip (7) to said cutting drum (9) when said auxiliary communication opening (30) reaches said auxiliary vacuum opening (27) during the rotation of said cutting drum (9).
5. The machine according to one or more of the preceding claims, further characterized in that said vacuum opening (25) and said auxiliary vacuum opening (27) have a substantially slot-type shape, said vacuum opening (25) extends along a direction that is substantially perpendicular to the axis of rotation (9a) of said cutting drum (9), said auxiliary vacuum opening (27) extends along a circular arc around the axis of rotation (9a) of said cutting drum (9).
6. The machine according to one or more of the preceding claims, further characterized in that said auxiliary vacuum opening (27) is arranged at a greater distance from the axis of rotation (9a) of said cutting drum (9) than said vacuum opening (25).
7. The machine according to one or more of the preceding claims, further characterized in that said cutting region (21) is formed by at least a portion of said distribution unit (20) that is elastically loaded against said cutting drum (9).
8. The machine according to one or more of the preceding claims, further characterized in that said cutting drum (9) comprises at least two frames (42a, 42b) that are fixed around said rotating drive rod (43) by means of detachable coupling means that are substantially and radially extended with respect to the axis of said drive rod (43).
9. The machine according to one or more of the preceding claims, further characterized in that said drive rod (43) is rotatably supported 5 by a bushing element (51) which is fixed to the machine support structure by means of a flange coupling (52).
10. The machine according to one or more of the preceding claims, further characterized in that each cutting device (14) comprises a respective box-type blade support body (53), which forms the respective suction chamber (15) and is detachably received in a corresponding receiving seat (54) formed in said cutting drum (9).
11. The machine according to one or more of the preceding claims, further characterized in that the respective portions (54a, 54b) of the receiving seat (54) of the box-type blade support body (53) of each cutting device (14) are formed in mutually facing regions 15 of said frames (42a, 42b).