MACHINE AND METHOD FOR LABELING CONTAINERS
The present invention relates to a machine and a method for labeling containers. Labeling machines are known which make it possible to automatically carry out the application of printed labels on containers, in general, and bottles, in particular. Typically, the labeling machines are provided with a transfer drum that makes it possible to apply, on each bottle that is progressively presented before the transfer drum, a label which is obtained by cutting a continuous ribbon of labels which is unwound from a reel. Before being applied on the corresponding bottle, each label receives, along its leading, or front, edge and along its trailing, or rear, edge with respect to its advancement direction, a quantity of glue from a gluing assembly, which can be constituted by a gluing roller or by a spraying assembly. Generally, in this type of labeling machine, the bottles are conveyed by a rotating carousel which is provided with a plurality of supports for the individual bottles, which are adapted to rotate the bottles about their own axis, and is provided with an unwinding roller which makes it possible to take the ribbon of labels from the reel and feed it to a cutting drum, on which, by way of cutting means, the ribbon is cut between one label and the next. Subsequently, the individual labels, once separated after cutting, are transferred from the cutting drum to the transfer drum. In particular, the labels are arranged so that they adhere to the transfer drum at respective sectors of the outer lateral surface of the transfer drum. Such sectors are angularly mutually spaced apart about the axis of the transfer drum and are separated from each other by a separation segment. Typically the gluing assembly is arranged so as to face the transfer drum and apply the glue at the leading and trailing edges of the individual labels placed in the sectors of the outer lateral surface of the transfer drum, before the labels are brought by that transfer drum to adhere to the corresponding bottles carried by the rotating carousel. In particular, if the gluing assembly is constituted by a gluing roller, then at opposite ends of the various sectors of the transfer drum are two adhesive bonding regions, which are in relief with respect to the main lateral surface of the transfer drum and which are defined by respective blocks called runners, on which the leading and trailing edges of the labels come to rest, so that when the labels pass in front of the gluing drum, the latter applies only two strips of glue to those labels. In order to prevent the labels from remaining attached to the gluing roller, they are kept adhered to the lateral surface of the transfer drum by way of holes, provided on the lateral surface of the transfer drum, which are connected to air suction means. During the operation of the labeling machine, since individual separated labels adhere to the transfer drum, it often happens that the transfer drum can be smeared with glue, which results in the machine having to be shut down in order to carry out the necessary cleaning thereof. If on the other hand the gluing assembly is constituted by a spraying assembly, then the latter, in order to enable the application of the glue on the labels at the high speeds with which the labels move on the transfer drum, is usually made up of a battery of several spray guns which are arranged laterally to the transfer drum. In particular, each one of such spray guns is provided with a plurality of glue dispenser nozzles which are directed toward the outer lateral surface of the transfer drum and which, at each activation of the corresponding spray gun, are each capable of emitting a given quantity of glue which is sprayed on the labels being conveyed by the transfer drum. In particular, the dispenser nozzles of each spray gun are arranged mutually side-by-side along a row that extends parallel to the direction of transverse extension of the labels, i.e. substantially parallel to the axis of the transfer drum, and are mutually spaced apart, along the row, by a distance that is dictated by technical requirements aimed at ensuring a valid and regular operation of the spray gun at high speeds. In this manner, the dispenser nozzles of each spray gun apply a corresponding plurality of droplets of glue on the labels, called glue spots, which are arranged along a row that is parallel to the direction of transverse extension of the labels and which are spaced apart, from each other, by a distance that is practically equal to the distance between the dispenser nozzles. In order to be capable of applying a row of droplets of glue on the labels with a distance between two consecutive droplets along the row that is smaller than the distance between the dispenser nozzles of the spray guns, the spray guns are arranged side by side, one after the other, along a direction parallel to the advancement direction of the labels and are arranged differently beside each other along a direction parallel to the axis of the transfer drum, so that the dispenser nozzles of each spray gun are arranged offset with respect to those of the other spray guns. The spray guns, thus arranged, are activated sequentially one after the other so that the droplets of glue applied by the spray guns after the first spray gun encountered by the label come to be positioned in an interleaved position between the droplets applied by each preceding spray gun. In order to enable the spray guns to dispense the glue one after the other very quickly, given the high speed of the labels conveyed by the transfer drum, they must work at relatively high levels of pressure of the glue, with consequent considerable production of glue vapors and risk of unwanted smearing of the components of the machine. The aim of the present invention is to provide a machine for labeling containers which is capable of improving the known art in one or more of the above mentioned aspects. Within this aim, an object of the present invention is to provide a machine for labeling containers that makes it possible to prevent unwanted smearing of the transfer drum or other components of the machine with glue. Another object of the present invention is to provide a machine for labeling containers that constitutes a considerable simplification in terms of construction and operation compared to traditional machines of this type which are fitted with a glue spraying assembly. Another object of the present invention is to provide a machine for labeling containers that can operate positively using only one spray gun. Another object of the present invention is to provide a machine for labeling containers that is capable of offering the widest guarantees of reliability and safety in its operation. Another object of the present invention is to provide a method for labeling containers that makes it possible to execute an optimal application of glue on the labels. Another object of the present invention is to provide a machine for labeling containers that is of low cost, so as to be competitive from a purely economic viewpoint as well. This aim and these and other objects which will become better apparent hereinafter are achieved by a machine for labeling containers, according to the invention, as defined in claim 1. Further characteristics and advantages of the present invention will become better apparent from the description of a preferred, but not exclusive, embodiment of the machine according to the invention, which is illustrated by way of non-limiting example in the accompanying drawings wherein: With reference to the figures, the machine for labeling containers, according to the invention, generally designated with the reference numeral 1, comprises conveyor means 2 that make it possible to move one or more labels 3 to be applied on the containers 4 to be labeled according to a advancement direction 100. Such conveyor means 2 comprise a transfer drum 5 which is actuated in rotation about its own axis 5 A spraying assembly 7 faces the transfer drum 5 and is intended to apply glue on the labels 3, in order to allow the subsequent adhesion of the latter to the corresponding containers 4. According to the invention, the spraying assembly 7 comprises at least one spray gun 8 which has a plate-like glue dispensing body 9 which faces the lateral surface of the transfer drum 5 and is passed through by a plurality of dispensing ports 10, which are adapted to connect the inside of the spray gun 8 with the outside. The dispensing ports 10 are, in particular, arranged mutually spaced apart along at least one row which extends substantially parallel to the axis 5 Control means 12 are further provided, which conveniently comprise an electronic controller and are functionally connected to the conveyor means 2 and to the spray gun 8 and the function of which is to actuate a slowing of the advancement speed of the labels 3, with respect to the spray gun 8, before actuating the activation of the spray gun 8 for executing the application of the glue on the labels 3. It should be noted that, according to a preferred embodiment, the spraying assembly 7 can be provided with only a single spray gun 8. With reference to the embodiment shown in Conveniently, the unwinding assembly 13 comprises two feeding rollers 13 Advantageously, in order to allow to the transfer drum 5 to receive the labeling ribbon 13 by making it adhere to its lateral surface, the transfer drum 5 is provided, on its lateral surface, with a plurality of suction holes, which are connected to air suction means. In particular, the transfer drum 5 is further rotationally actuated at a constant speed, which is synchronized with the speed of the conveyor 6, so as to be in phase with it and be able therefore to deliver a label to a corresponding container 4 arriving on the conveyor 6. Conveniently, the transfer drum 5 is provided with means for cutting the labeling ribbon 13, which are arranged on its lateral surface and can be activated on command by activation means, in order to carry out the cutting of the labeling ribbon 13 at the connecting region 15 between two consecutive labels 3 that are present along the labeling ribbon 14. In particular, the control means 12 activate the spray gun 8 so as to apply the glue on at least one of the labels 3 that are present along the labeling ribbon 14, before the cutting means are activated by the corresponding activation means, for the purpose of carrying out the separation of the label or labels 3, on which the spray gun 8 has applied the glue, from the labeling ribbon 14. Preferably, the means for cutting the labeling ribbon 13 are constituted by a plurality of cutting devices 16, which are mutually angularly spaced apart about the axis 5 For example, the cutting devices 16 can each be provided by a respective cutting knife 16 According to a possible alternative embodiment, shown in With reference to In practice, the first row 16 In particular, the two rows 16 Advantageously, the control means 12 are adapted to actuate the activation of the spray gun 8 in order to enable the application of such lines 17 In detail, the lines 17 More precisely, the line 17 Conveniently, the control means 12 are adapted to drive the unwinding assembly 13 in order to vary the speed with which the labeling ribbon 14 is fed to the transfer drum 5 by the unwinding assembly 13, during the rotation of the transfer drum. In particular, the control means 12 are capable of controlling the unwinding assembly 13 so as to be able to vary the speed of feeding the labeling ribbon 14 to the transfer drum 5 between at least two speeds, respectively a first speed, which is synchronized with respect to the speed of the transfer drum 5, so that the labeling ribbon 14 is entrained by the transfer drum 5 without sliding, and at least one second speed, which is lower than the first speed and, preferably, nil i.e. equal to zero. More specifically, the control means 12 actuate a slowing of the speed of feeding the labeling ribbon 14 to the transfer drum 5, in order to take it from the first speed to the second speed, at least at the arrival, at the spray gun 8, of the trailing edge 3 Once such slowing of the speed of feeding the labeling ribbon 14 has been actuated, the control means 12 actuate the activation of the spray gun 8, in order to apply, proximate to the trailing edge 3 Conveniently, such increase of the speed of feeding the labeling ribbon is actuated by the control means 12 after they actuated the activation of the cutting means in order to carry out the cutting of the labeling ribbon 14 at the connecting region 15 between the two consecutive labels 3 on which the spray gun 8 has applied the glue. More preferably, upon arrival, at the spray gun 8, of the trailing edge 3 During the stop or, in any case, the slowing of the advancement of the labeling ribbon 14, the transfer drum 5, continuing to rotate about its own axis 5 As a consequence, the label 3 that, of the two consecutive labels 3, is in front of the other, with respect to the advancement direction 100, no longer being connected to the labeling ribbon 14, can be entrained by the transfer drum 5 toward the corresponding container 4. Delving deeper into the details of the spray gun 8, the dispensing ports 10 each comprise a respective spray nozzle that makes it possible to create a glue spot 11 of uniform dimensions on the labels 3. Conveniently, the spray gun 8 is provided by a main body 8 It should be noted that the dispensing ports 10 can optionally be arranged along the respective row 16 In particular, conveniently, the distance between at least two dispensing ports 10 of one row 16 It is also possible for the dispensing ports 10 of one row 16 More specifically, for example, the distance between the dispensing ports 10 of one row 16 It should be noted that, according to a possible embodiment, the dispensing ports 10 at least of the second row 16, i.e. of the row intended to apply the line 17 Operation of the machine according to the invention is the following. In a first step of operation, the unwinding assembly 3 feeds the labeling ribbon 14 to the transfer drum 5 at a first speed which substantially corresponds to the peripheral speed of the transfer drum 5, so that the labeling ribbon 14 and the transfer drum 5 are synchronized with each other. With reference to At this point, as shown in In the meantime, the swiping of the transfer drum 5 on the labeling ribbon 14 which occurs as a result of reducing the advancement speed of the labeling ribbon 14 enables one of the cutting devices 16 on the transfer drum 5 to be brought toward the connecting region 15 between the two consecutive labels 3 which have received, respectively, the lines 17 At this point, the control means 12 actuate the unwinding assembly 13 in order to obtain the increase of the speed of the labeling ribbon 14, so that it can be progressively brought from the second speed up to the first speed. The increase in the speed of the labeling ribbon 14 by the unwinding assembly 13 occurs in such a way that, while the labeling ribbon 14 moves at a speed comprised between the second speed and the first speed, one of the cutting devices 14 will continue to progressively approach the connecting region 15 of the two consecutive labels 3 that have received the glue, as shown in Subsequently, as shown in At this point, operation resumes as described above. From the foregoing it can be seen that the invention is capable of fully achieving the set aim and objects. All the characteristics of the invention, indicated above as advantageous, convenient or similar, may also be missing or be substituted by equivalent characteristics. The individual characteristics set out in reference to general teachings or to specific embodiments may all be present in other embodiments or may substitute characteristics in such embodiments. The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. In practice the materials employed, provided they are compatible with the specific use, and the dimensions and shapes, may be any according to requirements. Moreover, all the details may be substituted by other, technically equivalent elements. The disclosures in Italian Patent Application No. 102018000006434 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs. A machine for labeling containers conveys, along an advancement direction, the labels to be applied, which have a transfer drum which is adapted to bring individual labels into contact with corresponding containers which are supported by a conveyor. A spraying assembly faces the transfer drum and is adapted to apply glue on the labels; the spraying assembly includes at least one spray gun which has a plate-like glue dispensing body which faces the lateral surface of the transfer drum and is passed through by a plurality of dispensing ports, which are arranged mutually spaced apart along at least one row which extends substantially parallel to the axis of the transfer drum; a controller is configured to actuate a slowing of the advancement speed of the labels with respect to the spray gun before actuating the activation of the spray gun for the application of the glue on the labels. 1-15. (canceled) 16. A machine for labeling containers, which comprises conveyor means for conveying, along an advancement direction, the labels to be applied, said conveyor means being provided with a transfer drum which is adapted to bring individual labels into contact with corresponding containers which are supported by a conveyor, a spraying assembly facing said transfer drum and being adapted to apply glue on the labels, wherein said spraying assembly comprises at least one spray gun which has a plate-like glue dispensing body which faces a lateral surface of said transfer drum and is passed through by a plurality of dispensing ports, which are configured to connect an inside of said spray gun to an outside and are mutually spaced apart along at least one row which extends substantially parallel to an axis of said transfer drum, in order to enable the application on the labels of at least one line of glue spots which extends transversely to the advancement direction of the labels, control means being provided which are functionally connected to said conveyor means and to said spray gun and being configured to actuate a slowing of an advancement speed of the labels with respect to said spray gun before an activation of said spray gun for the application of the glue on the labels. 17. The machine according to 18. The machine according to 19. The machine according to 20. The machine according to 21. The machine according to 22. The machine according to 23. The machine according to 24. The machine according to 25. The machine according to 26. The machine according to 27. A method for labeling containers, which comprises the steps of:
conveying at least one label by way of a transfer drum at a first advancement speed, substantially upon arrival or prior to the arrival of at least one portion of said at least one label substantially at a spray gun which faces said transfer drum, slowing the first advancement speed of said at least one label in order to bring it to a second advancement speed which is lower than said first advancement speed, applying at least one line of glue spots to said at least one label by way of said spray gun, increasing the advancement speed of said at least one label until said advanced speed returns to said first advancement speed, bringing, by way of said transfer drum, said at least one label with the glue applied into contact with a corresponding container. 28. The method according to feeding, at said first advancement speed, by way of an unwinding assembly, said transfer drum with at least one portion of a labeling ribbon on which a plurality of labels are printed continuously along its extension, slowing the first advancement speed at which the labeling ribbon is fed to the transfer drum down to said second advancement speed when the trailing edge and the leading edge of two consecutive labels which are present on the labeling ribbon reach said spray gun, activating said spray gun in order to apply a respective line of glue spots on the trailing edge and on the leading edge of said consecutive labels, increasing the speed at which said labeling ribbon is fed to said transfer drum up until said first speed. 29. The method according to cutting, by way of cutting means, said labeling ribbon at the connecting region between said consecutive labels on which the glue has been applied, conveying, by way of said transfer drum, the labels, separated after cutting, into contact with corresponding containers supported by a conveyor. 30. The method according to after the application of said lines of glue spots on the trailing edge and on the leading edge of said consecutive labels, feeding said labeling ribbon to said transfer drum at a speed that is substantially comprised between said first advancement speed and said second advancement speed, in order to allow a cutting device which is associated with said transfer drum to reach a connecting region between said consecutive labels, and with said cutting device at the connecting region between said consecutive labels, activating said cutting device in order to cut said labeling ribbon at the connecting region between said consecutive labels.





