Labelling machine

Abstract: Labelling machine for the attachment, with intermediate distances, of self-adhesive labels (4) which are situated successively on a substrate (3) in the shape of a band, on a continuously moving strip (24), which machine, thus, comprises a peeling and attaching unit (7-8) consisting of a peeling mechanism (7) for peeling the labels (4) off this substrate (3), and a transport mechanism (8) for bringing the substrate (3) to the aforementioned peeling mechanism (7) and putting the peeled labels (4) onto the strip (24), characterized in that the transport mechanism (8) for bringing the substrate (3) to the aforementioned peeling mechanism (7) and to bring the peeled-off labels (4) on the strip (24) comprises at least one transport element (13;14) for the transport of the substrate (3) with labels (4) to the peeling mechanism (7) or a peeled-off label (4) to the strip (24); driving means (15-17;16-17) for driving this transport element (13;14) with a variable speed and means (18-19-20;21-22-23) for holding the substrate (3) with labels (4), without a direct contact, against a part of the transport element (13) and/or for holding a peeled-off label (4), with its adhesive side directed outward, against a part of the transport element (14) as long as the label (4) is not glued onto the strip (24).

Description: The invention relates to a method for attaching self-adhesive labels which are situated successively on a substrate in the shape of a band, according to which method the substrate with labels is fed by means of at least a first transport element to a peeling mechanism, the labels are peeled off from the substrate and the labels are transported by means of a second transport element to a second substrate whereon it is glued, the labels being hold with their adhesive side directed outward, against a part of the second transport element as long as they are not glued to said other substrate. A method of this kind, intended for the attachment of self-adhesive labels to bottles, is disclosed in GB-A-2.221.206. The substrate with labels situated at a relatively great distance one from the other, is supplied from a continuously driven supply drum by means of a continuously rotating feeder roller engaging the substrate after the peeling off of the labels. The peeled-off labels are also continuously transported by the second transport element which is a vacuum drum. The speed of the vacuum drum is adjusted such that its outer surface travels at the same speed as the speed of advance of the conveyor supporting the bottles. The speed of the feeder roller is also adjusted and this adjustment is controlled by a label position sensor and a sensor detecting pitch marks on the vacuum drum, such that the front edge of each successive label arrives at the peeling mechanism exactly is a vacuum passage of the vacuum drum arrives at this peeling mechanism. Labelling machines are also used for attaching address address labels on letters which are printed as a continuous strip and subsequently cut to length. The problem with such machines is that the labels are situated on the substrate at a much smaller distance, mostly only 2 to 4 mm, from each other than the distance which has to remain between them when they are glued onto the strip and which may, for example, be 30 cm. In known labelling machines, the peeling mechanism is a knife situated directly above the strip, such that the peeled labels directly drop onto the strip where they are pressed on this strip by means of a roller. The transport mechanism consists of a winding mechanism with a driven roller on which the empty substrate is wound up, as a result of which, consequently, the substrate with labels is wound off from the roll at which it had been wound up and is drawn over the knife. In these known labelling machines, the aforementioned problem is solved by driving the drawing mechanism intermittently and thus drawing the substrate successively over a distance over the knife. This means, that each time a label has to be glued on the strip, the roll of the winding mechanism, during the actual attachment, has to be accelerated very fast from a standstill up to its circumferential speed, and consequently the speed of the substrate, is equal to the speed of the strip, and consequently has to move for a short period of time with this speed, and thereafter must come back to a standstill very fast. This sequence of accelerations and decelerations of the band with labels has as a consequence that it is impossible to realize high speeds of the strip. This strip, coming from the printing machine with a speed which amounts to 375 m/min, must be decelerated. This invention aims at a method for attaching self-adhesive labels which does not show this disadvantage and other disadvantages and allows a very high speed of the strip on which the labels have to be attached. According to the invention, this aim is achieved in that that the substrate with the labels is successively accelerated to an intermediate speed and decelerated by the first transport element, the peeled off labels being accelerated by means of the second transport element from the intermediate speed to the speed sequence at the moment of applying the label to the second substrate, whereafter the second transport element is decelerated to the intermediate speed for catching another peeled off label. A peeled-off label is not directly attached to the substrate but to the second transport element, with its adhesive side directed outward. The acceleration of the labels is performed in two steps, a first step by the first transport element and a second step by the second transport element, as a result of which the two transport elements have each to perform a smaller acceleration than in the case that a single transport element has to realise the complete acceleration. The second transport element stays in motion with as its minimum circumferential speed the maximum circumferential speed of the first transport element. Preferably each label peeled off by the peeling mechanism is individually accelerated, by means of the second transport element from the intermediate speed to the speed sequence at the moment of applying the label to the second substrate, whereafter the second transport element is decelerated to the intermediate speed for catching the following peeled off label. The labels may be accelerated as well before peeling off as thereafter by means of a rotating drum, and during acceleration of the peeled off labels these labels are hold with their adhesive side directed outward by means of a vacuum or an electrostatic charge. This invention also relates to a labelling machine for the attachment, with intermediate distances, of self-adhesive labels which are situated successively on a substrate in the shape of a band, which machine comprises a peeling mechanism for peeling the labels off this substrate, and a transport mechanism comprising at least one transport element for the transport of the substrate with labels, driving means for driving this first transport element, a second transport element for the transport of a peeled-off label to another substrate, driving means for driving separately this second transport element, and means for holding without a direct contact a peeled-off label, with its adhesive side directed outward, against a part of the second transport element as long as the label is not glued to said other substrate. Without means for holding the label without direct contact against part of the second transport element, the transport of peeled-off labels would not be possible. Means requiring a direct contact to the labels are not useful, in consideration of the fact that the peeled-off labels are transported through the transport element with their adhesive side directed outward. A labelling machine of this kind is disclosed in the already discussed GB-A-2.221.206. For the transport of the peeled-off labels, the machine comprises a vacuum drum, the means for holding a peeled-off label against this drum being means for creating a vacuum inside the drum. The use of means for holding labels without direct contact against a transport drum in a labelling machine, more particularly the use of means for creating a vacuum in said drum is known from DE-U-91 02 676.8. However the labels are not self-adhesive and are not peeled-off. In a labeling machine according to the invention, particularly suitable for performing the above mentioned method of the invention, the means for holding without a direct contact the substrate and/or a peeled-off label are means for electrostatically charging at least a part of the exterior side of this transport element, for example, in order to charge an electrically nonconducting exterior surface of the transport element. Without the last-mentioned means for holding, a transport of the substrate by means of a transport element which is fast accelerated an decelerated again, is not possible in a precise manner, due to the slippage which inevitably will be created. The second transport element may be a drum and also the first transport element may be a drum. When the transport element is a drum, the driving means of it may comprise an electric motor which is situated within the drum. This drum can be executed in a light manner from composite material, this is synthetic material reinforced with fibers, which is coated at the exterior side with an electrostatically chargeable layer. With the intention of better showing the characteristics of the invention, a preferred form of embodiment of a labelling machine according to the invention is described hereafter, by means of example without any limitative character, with respect to the accompanying drawings, wherein: figure 1 schematically represents a front elevational view of a labelling machine according to the invention; figure 2, at a larger scale, represents the part which is indicated by F2 in figure 1; figure 3 represents a cross-section according to the line III-III in figure 2, drawn at a still larger scale; figure 4 represents a diagram of the motors of the labelling machine of figures 1 to 3 in function of the time. The labelling machine represented in figure 1 comprises a locomotive frame 1 on which, from the top to the bottom, substantially the following parts are mounted: a carrier 2 for a wound-up substrate 3 with labels 4, a supply mechanism 5 for this substrate 3, a vacuum chamber 6, and a peeling and attaching unit consisting of a peeling mechanism 7 and a transport mechanism 8. The carrier 2 is a horizontal shaft which is fixed at the top of the frame 1 and upon which a band, wound-up upon itself or upon a roller, is placed, which band consists of a substrate 3, for example, of paper coated with silicones, and of labels 4 which are attached thereupon at a small mutual distance of several millimeters, for example 3,16 mm, and which are directed with their longitudinal direction perpendicular to the longitudinal direction of the substrate 3. The supply mechanism 5 comprises a drum 10 which is borne on the frame 1 and driven by an electric motor 9, and a tensioning roller 11 between the drum 11 and the carrier 2. The vacuum chamber 6 is connected to a vacuum pump 12 and is sufficiently large in order to contain a buffer supply of the substrate 3 with labels 4. In this vacuum chamber 6, detectors, not represented in the figures, such as photocells, are installed which control the motor 9 of the supply mechanism 5 in function of the supply of substrate 3 in the vacuum chamber 6. The transport mechanism 8 comprises two transport elements, namely a first transport element formed by a drum 13, and a second transport element formed by a drum 14, between which the peeling mechanism 7 is situated. The transport mechanism 8 also comprises driving means 15-16-17 for driving the drums 13 and 14, consisting of motors 15 and 16 and of a control 17 for these motors. Furthermore, the transport mechanism 8 comprises means 18-19-20 for holding the substrate 3, without direct contact to this latter, during its transport against a part of the drum 13, and means 21-22-23 for holding, without direct contact to the peeled-off labels 4, these labels 4 against a part of the drum 4 until they are glued to the strip 24. This strip 24, for example, is a chain form onto which, at regular distances from each other, for example, on each page, a label 4 has to be glued. As shown in detail in figure 2, the aforementioned means 18-19-20 are means for electrostatically charging a part of the exterior of the drum 13, namely its shell, and these means 18-19-20 consist of, on the one hand, an electrically nonconductive and electrostatically chargeable coating 18 of the shell of the drum 13 and, on the other hand, of two electrodes 19 and 20 between which a voltage field is created and which are arranged diametrically opposed to each other at a small distance to the circumference of the drum 13, in such a manner that one of the electrodes is situated opposite to a part of the drum 13 with which the substrate 3 is in contact during its transport. These electrodes 19 and 20 are in contact with a voltage supply, not represented in the drawings, with a very high voltage of, for example, 15 kV which gives to the electrodes 19 and 20 an opposed, but cyclically altering polarity. These electrodes 19 and 20 cause a positive and a negative voltage or electrostatic charge on different parts of the coating 18 of the drum 13. The electrostatically chargeable coating 18, in particular, is a coating from synthetic material, for example, a foil of high-pressure polyethylene. The means 21-22-23 belonging to the drum 14 are, in an analogous manner, means for electrostatically charging the exterior of the drum 14 which are formed of, on the one hand, a similar electrically nonconductive and electrostatically chargeable coating 21 of the shell of the drum 14, and, on the other hand, of two electrodes 22 and 23 between which a voltage field cyclically altering its direction is formed, whereby an electrode is arranged opposite to the part of the drum 14 through which a label 4 is transported, and the other electrode is situated diametrically opposed thereto. In a variant, the electric charging of the electrostatically chargeable coating 18 or 21 can be obtained by using instead of two electrodes only a single electrode which, for the largest part, surrounds the drum 13 or 14, whereas a discharger then is installed between the extremities of this electrode. The drum 13 consists of a very thin wall with, for example, a thickness of 0,6 mm, of a very strong and light-weight material, in particular a composite material, this is synthetic material reinforced with fibers, such as glass fibers or carbon fibers, whereby the shell is coated at its exterior with the aforementioned coating 18, 21 respectively. The total weight of the drum 13 is extremely small, for example, less than 50 g, so that the inertia of this drum 13 also is very small. The drum 13, as represented in detail in figure 3, is open at one extremity and borne in the proximity of this extremity by means of bearings 25 around the housing 26 of the motor 15 driving this drum 13 and thus situated within the drum 13. This motor 15 is fixed, by the intermediary of its housing 26, at the frame 1. The shaft 27 of this motor 15 is fixed at the closed extremity of the drum 13. The drum 14 is identical to the drum 13 and mounted turnable in the same manner around the motor 16 driving it. The speed with which the motor 15 drives the drum 13 or the motor 16 drives the drum 14 might be restricted by overheating of the motor 15 or 16. In order to allow for a higher speed, in such cases a cooling mechanism may be provided for undercooling the motor 15 or 16 to negative temperatures. The peeling mechanism 7 consists of a knife 28 which is fixed at the frame 1 between the drums 13 and 14 and, practically against the drum 14, has an edge around which the substrate 3, by means of a roller 29 placed above the knife 28, is forced to bend over an angle of approximately 180 degrees. Between its aforementioned edge and the drum 13, the knife 28 forms a guidance for the substrate 3 with the labels 4. Above the drum 13, also a number of guiding rollers 30 is installed for guiding the substrate 3 from the vacuum chamber 6 to the drum 13, and a number of guiding rollers 31 for guiding the empty substrate 3 starting from the roller 29, over a part of the circumference of the drum 13 and further to a discharge mechanism 32 consisting of two rollers 33 and 34 between which the substrate 3 is clamped and which are driven by motors 35. In a variant, these rollers 33 and 34 may be replaced by knives. Beneath this discharge mechanism 32, a discharge channel 36 is situated which ends up in a waste container or at a windup mechanism for the empty substrate 3. The aforementioned control 17 controls the motors 15 and 16 for driving the drums 13 and 14 separately, in function of data which are put in by the user on a control panel 27 which is connected therewith, and in function of data from two detectors 38 and 39 and an encoder 40. The detectors 38 and 39 which can detect a label 4 and, for instance, are photocells, are respectively placed just past the edge of the knife 28, where a loosened label 4 touches the drum 14, and at a distance therefrom, opposite to the drum 14. The encoder 40 is situated opposite to the strip 24 and detects markings in order to give in this manner information of the position and, thereby, of the speed of the strip 24. The control 17 controls the motors 15 and 16 in such a manner that the drums 13 and 14 are driven in a contrary sense with varying speed, whereby the drum 13 can be accelerated from a standstill to a well-defined speed and the drum 14 can be accelerated from approximately this well-defined speed to its circumferential speed which is equal to the speed of the strip 24, as will be described hereafter, in the explanation of the functioning, in a more detailed manner. The functioning of the labelling machine described above is simple and as follows. A roll of substrate 3 with labels 4 is placed onto the carrier 2, and the front end of the substrate 3 is brought over the supply mechanism 4 and the vacuum chamber 6 up into the peeling and attaching unit 7-8. The strip 24 on which the labels 4 have to be attached is guided along the bottom side of the drum 14. On the control panel 37, the various parameters are regulated, such as dimensions of the labels 4, their mutual distance and the distance between the labels on the strip 24. After the machine has been started, the supply mechanism 5 provides in that a sufficient supply of the substrate 3 is present in the vacuum chamber 6 in order to provide for a tensionless supply of the substrate 3 to the transport mechanism 8. The control 17 controls the motor 15 of the drum 13 in such a manner that the rotational speed thereof varies according to the line 41 in the diagram represented in figure 4 which shows the number of revolutions per minute V in function of the time t in milliseconds. As a result of this, the substrate 3 with the labels 4 on top thereof, which, due to the electrostatic charging of the coating 18 as a result of the electric field between the electrodes 19 and 20, is drawn against the drum 13, is moved along with this drum 13 without any slippage, as indicated in figure 2 by the arrows 42. Hereby, the drum 13 is accelerated from the standstill to a maximum speed V1 which corresponds to an intermediary speed of a label 4 and is, for example, 800 revolutions per minute. This acceleration is started by the control 17 at the moment when it receives a signal from the encoder 40. The drum 14 is revolved at its aforementioned maximum speed for a short period of time and subsequently stopped. The complete above-described acceleration and deceleration of the drum 13 takes place in several milliseconds and corresponds to the dimension according to the circumference of the drum 13 of one label 4 and an intermediate distance between two labels 4. This means that during this cycle one label 4 is pushed and drawn past the edge of the knife 28 and therefore one label 4 is peeled off by this knife 28 and, in the period of time in which the drum 13 revolves with its maximum speed V1 and the label 4, thus, is moved at the intermediary speed, is transferred to the drum 14. The empty substrate 3 is moved over the same distance as the label 4 during the above-described displacement thereof, and the empty substrate 3, by means of the electrostatic charge of the coating 18 of the drum 13, is drawn against this latter, at the opposite side in respect to the substrate 3 with the labels 4, and thereby brought to the supply mechanism 32. At the moment of the transfer of the peeled-off label 4, the control 17 is controlling the motor 16 of the drum 14 in such a manner that this drum 14, at the aforementioned maximum speed, revolves in the opposite sense and therefore the circumferential speed of this drum 14 is equal to V1. Just before that, as represented by line 43 in the diagram of figure 4, the drum 14 has been decelerated from a higher number of revolutions, for example, 1150 revolutions per minute, to the aforementioned speed. As soon as the detector 38 detects that a label 4 has passed, which means that this label 4 is situated completely on the drum 14, with its glue layer directed outward, the control 17 accelerates the motor 16 up to its maximum speed V2. By means of the electrostatic charge of the coating 21 as a result of the electric field between the electrodes 22 and 23, this label 4 is drawn against the drum 14 and moved along with this drum 14, as represented in figure 2 by means of the arrows. The acceleration starts when the detector 29 detects the front end of the label 4, this is after a revolution of approximately 38° of the drum 14, after which this drum 14 is driven further with its maximum speed V2 corresponding to a circumferential speed which is equal to the speed of the strip 24, during a sufficient period of time so that the label 4 will reach the strip 24 and, by the contact of this strip 24 with the drum 14, will be glued upon the strip 24. Subsequently, the control 17 again commands the deceleration of the motor 16 up to the intermediate speed V1, as represented by line 43 in figure 4. The above-described cycle is repeated for the attachment of a succeeding label 4 on the strip 24. The speeds of the drums 13 and 14 are mutually coordinated by the control 17 in such a manner that a label 4, thus, first is accelerated to an intermediate speed on the drum 13, at this speed is taken over by the drum 14 and subsequently is further accelerated to the speed of the strip 24 in order to be glued at this speed onto the continuously moving strip 24. Due to the acceleration in two steps and the small inertion of the drums 13 and 14 which enable a fast acceleration, the speed of this strip 24 be relatively high. In an alternative embodiment, the drum 10 of the supply mechanism 5 can be contructed in an analogous manner around the motor 9, such as the drums 13 and 14, and thus also comprise an electrostatically chargeable coating which can be charged by electrodes. It is not necessary that the substrate 3 with the labels 4 is held against a part of the drum 13 by means of electrostatic charging. Other means may be applied to this end insofar they offer little or no resistance against the speed alterations of the drum 13 or, in other words, do not directly touch this substrate. The same is valid for the labels 4 against the drum 14, however, it has to be considered that the label is directed with its glue towards the outside and therefore no elements may be brought against this glue layer. This invention is in no way limited to the form of embodiment described heretofore and represented in the figures, on the contrary may such labelling machine be constructed in various variants without leaving the scope of the invention as disclosed in the following claims.

Claims: Method for attaching self-adhesive labels (4) which are situated successively on a substrate (3) in the shape of a band, according to which method a first substrate (3) with labels (4) is fed by means of at least a first transport element (13) to a peeling mechanism (7) the first substrate (3) with labels (4) being held against said first transport element (13), the labels (4) are peeled off from the first substrate (3) and the labels (4) are transported by means of a second transport element (14) to a second substrate (24) whereon they are glued, the labels (4) being held with their adhesive side directed outward, against a part of the second transport element (13) as long as they are not glued to said second substrate (24), characterized in that the first substrate (3) with labels (4) and/or the peeled-off-labels are held against a part of the respective first and/or second transport element (13, 14), and the first substrate (3) with the labels (4) is successively accelerated to an intermediate speed and decelerated by the first transport element (13), the peeled off labels (4) being accelerated by means of the second transport element (14) from the intermediate speed to the speed sequence at the moment of applying the label (4) to the second substrate (24), whereafter the second transport element (14) is decelerated to the intermediate speed for catching another peeled off label (4). Method of claim 1, characterized in that each label (4) peeled off by the peeling mechanism (7) is individually accelerated by means of the second transport element (14) from the intermediate speed to the speed sequence at the moment of applying the label (4) to the second substrate (24), whereafter the second transport element (14) is decelerated to the intermediate speed for catching the following peeled off label (4). Method according to claim 1 of 2, characterized in that during the first acceleration, the labels (4) are intermittently accelerated from a standstill to the intermediate speed. Method according to any one of claims 1 to 3, characterized in that the labels (4) are accelerated before peeling off by means of a rotating drum (13). Method according to any one of claims 1 to 4, characterized in that the labels (4) are accelerated after peeling off by means of a rotating drum (14). Method according to any one of claims 1 to 5, characterized in that during acceleration of the peeled off labels (4) these labels (4) are held with their adhesive side directed outward by means of a vacuum or an electrostatic charge. Method according to any one of claims 1 to 6, characterized in that during acceleration of the substrate (3) with the labels (4) this substrate (3) is held on the first transport element (13) by means of a vacuum or an electrostatic charge. Labelling machine for the attachment, with intermediate distances, of self-adhesive labels (4) which are situated successively on a first substrate (3) in the shape of a band, which machine comprises a peeling mechanism (7) for peeling the labels (4) off the first substrate (3), and a transport mechanism (8) comprising at least one transport element (13) for the transport of the first substrate (3) with labels (4), driving means (15-17) for driving this first transport element (13), a second transport element (14) for the transport of a peeled-off label (4) to a second substrate, driving means (16-17) for driving separately this second transport element (14), and means (21-22-23) for holding without a direct contact a peeled-off label (4), with its adhesive side directed outward, against a part of the second transport element (14) as long as the label (4) is not glued on the second substrate, characterized in that the means (18-19-20;21-22-23) for holding the first substrate (3) with labels (4) against a part of the first transport element (13) and/or the peeled off labels (4) against a part of the second transport element (14) without direct contact are means for electrostatically charging at least a part of the exterior side of the respective first and/or second transport element (13,14). Labelling machine according to claim 8, characterized in that the aforementioned means (18-19-20;21-22-23) are means for electrostatically charging an electrically nonconductive exterior surface of this transport element (13;14). Labelling machine according to claim 9, characterized in that the aforementioned means (18-19-20;21-22-23) for electrostatically charging comprise an electrostatically chargeable coating (18;21) of the transport element (13;14) and two electrodes (19 and 20; 22 and 23) placed opposite to each other at opposite sides of this transport element (13;14). Labelling machine according to any one of the claims 8 to 11, characterized that the second transport element (14) comprises a drum. Labelling machine according to claim 11, characterized in that also the first transport element (13) comprises a drum. Labelling machine according to claim 12, characterized in that the driving means (15-16-17) comprise an electric motor (15,16) for each of the drums (13,14) of the transport elements and a control (17) controlling these motors (15,16) in such way that the motor (15) driving the drum (13) of the first transport element is accelerated and decelerated between a minimum circumferential speed, which may be zero, and an intermediate circumferential speed, while the motor (16) driving the other drum (14) of the second transport element is accelerated and decelerated between this intermediate circumferential speed and the desired circumferential speed which coincides with the speed of the label (4) during its attachement to the other substrate, which consists of a strip (24). Labelling machine according to claim 13, characterized in that the control (17) is connected to an encoder (40) which detects data on the strip (24) and to two detectors (38,39) which are installed opposite to the drum (14) of the second transport element, whereby one of the detectors (38) is installed opposite to the place where a peeled-off label (4) comes into contact with this drum (14). Labelling machine according to any one of claims 11 to 14, characterized in that the driving means (15-17; 16-17) of a drum (13;14) comprise an electric motor (15;16) which is installed within the drum (13;14). Labelling machine according to any one of claims 11 to 15, characterized in that the drum (13;14) is manufactured of composite material. Labelling machine according to any of claims 8 to 16, characterized in that it comprises a vacuum chamber (6) which is installed before the transport element (13;14), and a supply mechanism (5) for supplying substrate (3) with labels (4) to the vacuum chamber (6), in such a manner that a buffer supply of substrate (3) with labels (4) is always present therein.

Inventors: VAN DEN BERGH MARC FRANS STEFA, VAN DEN BERGH, MARC FRANS STEFAAN MARIA
Applicants: DEN BERGH ENGINEERING VAN, VAN DEN BERGH ENGINEERING
Application year: 1997
Main classification: B65C9
IPC codes: B65C9