Abstract:
A method and apparatus for applying individual flat material segment to be separated from a flat material web to products. The products are moved continuously past the application device. The device includes a separation unit for separating the flat material segment from the flat material web. The device also includes an application unit for applying the flat material segment to the product, and a buffer unit between the separation unit and the application unit for the intermediate storage of the flat material segment so as to decouple the feeds at the separation unit and the application unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a National Phase Patent Application of International Application Number PCT/EP03/01134, filed on Feb. 5, 2003, which claims priority of German Patent Application Number 102 06 705.8, filed Feb. 18, 2002. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to an application device for applying segments of flat material, in particular labels, and a method of applying such segments of flat material to a product.  
       BACKGROUND  
       [0003]     Conventional self-adhesive labels are customarily made by firstly producing a flat material web of which one side has an adhesive layer and the other side can be printed upon by means of a printing unit. In order to ensure that the self-adhesive flat material web does not adhere to conveyor rollers, printing rollers, and the like in the printing unit for printing the labels, the self-adhesive flat material web is covered with a carrier material web at the side of the adhesive layer. That self-adhesive flat material web is generally wound up to form a roll whereby handling of the self-adhesive flat material web and its storage are facilitated.  
         [0004]     Application devices have previously been used to apply predominantly pre-stamped, self-adhesive labels having predetermined dimensions of length and width. The maximum width of a label is predetermined by the width of the flat material web. Pre-stamped labels of that kind can be applied continuously without stopping the product to be labelled. If, however, labels of a different length are to be applied to products, the application device or labelling machine has to be reconfigured, which requires the application device to be stopped and results in an increase in labelling costs per product.  
         [0005]     In conventional “linerless” labels, the self-adhesive flat material web does not have any carrier material web. Such a flat material web can be rolled up like a conventional adhesive strip. This permits an increased level of productivity by virtue of more efficient rolling and, thus, shorter setting times. In addition, linerless labels are particularly environmentally-friendly, as there is no waste of silicone-bearing carrier material. Further advantages are reduced cost in stockkeeping, transport, and waste disposal due to the processing of up to 50% more label material. In addition, linerless labels are not pre-stamped but are continuously drawn off a roll and cut to the required length. In that case, labels of differing lengths can be advantageously produced from the same flat material web.  
         [0006]     Just as in the case of the linerless labels, labels are also produced from a flat material web with a carrier material that are not pre-stamped, but cut off the flat material web at a desired length.  
         [0007]     If in industrial manufacture, for example, large numbers of products are to be provided with labels of varying lengths at a high throughput rate, the use of a self-adhesive flat material web lends itself to labels, with or without a carrier material web, in a non-pre-stamped form. Accordingly, an application device in that use can produce labels of the desired dimensions in an extremely flexible fashion and apply them to products.  
         [0008]     The necessary cutting operation in that case, which separates a flat material segment from a flat material web with or without a carrier material for the production of a label, suffers from a serious disadvantage. For each individual label, the feed of the flat material web must be stopped in order to permit the label to be separated in a trouble-free manner. This procedure involves stopping, or at least decelerating, the products to be labelled at the application device. The consequence of this is a lower product throughput rate. Accordingly, such a stop-and-go mode of operation involves a higher level of material wear and energy consumption.  
       OBJECT  
       [0009]     The object of the present invention is to provide a device and a method of applying or putting on self-adhesive labels, wherein, in particular, the labels can be continuously applied without stopping the products to be labelled. The invention further seeks to provide a simple structure for the application device and easy and trouble-free handling. In addition, the invention seeks to maximize the flexibility with which different length labels can be applied. One or more of the objects may be met with various embodiments of the invention.  
       SUMMARY  
       [0010]     One embodiment of an application device according to the invention has a buffer or a buffer unit between a separation unit for separating a flat material segment from the flat material web. The embodiment also includes an application unit for applying such a flat material segment in the form of a label to a product. The buffer or the buffer unit advantageously decouples the operation of applying the labels to the products from the separation operation which takes a finite period of time. The cycle rate of the products to be labelled is thus independent of the duration of the separation operation for a label.  
         [0011]     The buffer or the buffer unit of the application device according to various embodiments of the invention may include a variable loop formed from the flat material web between the separation unit and the application unit prior to each separation operation. The length of that loop represents the flat material web portion which can be taken from the buffer unit. The loop is at least as long as the distance that is covered by the surface of a product to be labelled at the application unit during the duration of the separation operation of the flat material segment.  
         [0012]     The loop is formed in the buffer unit by controlling the feed speed of the flat material web in such a way that, at least temporarily, between two separation operations, it runs at a higher feed speed than the speed of the products to be labelled, as they move past the application device.  
         [0013]     For that purpose, the buffer unit has a controlledly driven feed roller and a pressure roller that is spaced from the feed roller in the feed direction of the flat material web. The feed roller can be arranged in a detachment unit and can advance the flat material segment at a speed that is predetermined at any time. The pressure roller is provided for pressing the flat material segment against the surface of the product at the application unit. Both the feed roller and also the pressure roller are arranged parallel to each other and to the plane defined by the surface of the product. In that way, a dispensed label is discharged by the application device, advantageously aligned with respect to the surface to be labelled. It is also possible to provide a controlled drive at the pressure roller.  
         [0014]     For controlling the feed speed, the application device can have a control unit. The control unit controls the speed of the driven feed roller of the buffer unit as described above so that, between two separation operations, the arrangement guarantees the formation of the loop of the required length from the flat material web. To detect the feed speeds of the flat material web at the detachment unit, a sensor can be provided at the detachment unit. The sensor communicates the detected speed to the control unit. Alternatively, a sensor can be provided at the application unit or the conveyor device for detecting the speed of the products at the application unit, which transmits the speed to the control unit.  
         [0015]     The flat material web can comprise both a carrier material web, on which a self-adhesive label material web is disposed, and a carrier material-less label web. In the embodiment with a carrier material web, it is removed from the flat material web upstream of the separation unit.  
         [0016]     In one embodiment of a method of applying individual flat material segments, the flat material web is fed by a feed unit. Each flat material segment is separated by a separating unit and applied to a product by an application unit. The feed of the flat material web is then decoupled from the feed of the flat material segments by a buffer unit.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a schematic side view of an application device according to one embodiment of the invention; and  
         [0018]      FIG. 2  shows an exploded detail view D of the embodiment shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0019]      FIGS. 1 and 2  show an application device  10  according to one embodiment of the invention. The device  10  is used to apply labels E or the like to at least a part of the surface O of products P which are moved by a conveyor device F past the application device  10  from right to left in a horizontally extending plane. The housing  11 , which surrounds the assemblies of the device  10 , is partially removed in  FIGS. 1 and 2 . Only the substantially vertically extending rear wall  11   a  and a carrier plate  11   b  mounted thereon are illustrated.  
         [0020]     In the illustrated embodiment of the application device  10 , the labels E are made from a flat material web  20 , which comprises a self-adhesive label web  22  and a carrier material web  24  that is disposed on the adhesive side  22   a  of the self-adhesive label web  22 . The flat material web  20  is loaded in the form of a supply roll RV into the device  10  by fitting the roll RV on a spindle A 1 , which is shown at the top right in  FIG. 1 , and which projects perpendicularly from the rear wall  11   a.  The flat material web  20  is fed from the supply roll RV by way of horizontally oriented guide rollers R 1 , R 2 , R 3  to a detachment unit  30 . In the detachment unit  30 , the label web  22  is detached from the carrier material web  24  by being pulled therefrom at a dispensing edge. The carrier material web  24 , without the label web  22 , is then guided from the detachment unit  30  to a waste roll RA, which is shown at the right in  FIG. 1 , and which is fitted on a spindle A 2  projecting perpendicularly from the rear wall  11   a,  and is wound up by the roll RA.  
         [0021]     Adjoining the detachment unit  30  in the direction of conveying movement of the flat material web  22  is a printing unit  40 . In the printing unit  40 , segments of the label web  22  can be printed upon with the desired information. Printing can take place, for example, with a known thermotransfer printing process. A segment of the label web  22 , which is printed upon in that way, is then fed to a separation unit  50 .  
         [0022]     The detachment unit  30  includes a controlledly driven feed roller  30   a  for the controlled advancement of the label web  22  in the direction of the separation unit  50  or an application unit  60  adjoining the separation unit  50  in the feed direction. The label web  22  that is supplied from the printing unit  40  is engaged by a guide, and then fed without slippage, by the controlled feed roller  30  to the application unit  60 . The feed roller  30   a  is controlled by a control unit. The feed speed can be defined at any time.  
         [0023]     The application unit  60  substantially comprises a pressure roller  60   a,  which is oriented horizontally in relation to the plane defined by the product surface O to be labelled, and which presses the label E against the surface O of the product P. The free-running pressure roller  60   a  can be resiliently mounted to be reversibly displaceable in the direction of the surface of the product P so that, at any time, a sufficient pressing force can be applied by way of the pressure roller  60   a  for fold-free application of the label E. The free-running pressure roller  60   a  can additionally be provided with a sensor element  62  in such a way as to permit the speed of the products P to be labelled to be detected. The sensor may also detect faults and problems with the system, such as an absence of the products P. It will be appreciated that such a sensor system can also be provided independently of the pressure roller  60   a.    
         [0024]      FIG. 2  shows additional detail of the application device  10  of  FIG. 1 , including the separation unit  50 , which adjoins the printing unit  40 ; the application unit  60 ; and one embodiment of a buffer unit  70  arranged therebetween. The buffer unit  70  comprises the controlled feed roller  30   a  and the pressure roller  60   a,  between which a loop  80  of the flat material web  22  can be formed as a buffer, the loop  80  being variable from the label E to be applied. The buffer unit  70  makes it possible to decouple the application operation from the separation operation in respect of a label E. This is achieved by the specific and targeted co-operation of the controlled feed roller  30   a  and the pressure roller  60   a  of the buffer unit  70 . The necessary co-ordination between the feed speed at the feed roller  30   a  and the conveyor speed of the product or products P is ensured by the control unit  34  in the application device.  
         [0025]     The control unit  34  ensures suitable time control of the feed speed of the label web  22  in the separation unit  50  by means of the controlledly driven feed roller  30   a  in relation to the speed of the product or products P to be labelled on the conveyor device F at the application unit  60 . This provides for filling the buffer unit  70 , that is to say forming the loop  80 , between two separation operations in the separation unit  50 . In that respect, in principle the feed speed of the flat material web  20  or the label web  22  between two separation operations can be constantly higher than the speed of the products P on the conveyor device F. This corresponds to a constant speed profile (v E (t)=constant) of the feed speed v E  between two separation operations. It is, however, also possible to ‘fill up’ the buffer unit  70  with a loop  80 , with a speed profile of a different configuration (v E =v E (t)). For example, immediately after a separation operation, beginning with a strongly accelerated feed movement, the flat material web  20  or the label web  22  can be advanced very quickly and then braked linearly or exponentially. As a feedback means, the current speeds of the product or products P at the application device  10  and the label web  22  at the separation unit  50  can be made available to the control unit by way of sensors  32 ,  62 , F 2  which can be provided, for example, at the feed roller  30   a,  the pressure roller  60   a,  and the conveyor device F.  
         [0026]     If the speed of the products P at the application device  10  is v p  and if the separation operation for separating a label E, requires the period of time Δt, then the loop length L s1  which is to be accommodated in the buffer unit  70  approximately corresponds to v p ·Δt. With the period of time t E  for applying a label E the feed speed v E  in a first approximation for forming the loop is at least (v P ·t E )/(t E −Δt). Due to dead time in the feed speed control procedures, the speed in practice is to be selected at a higher value.  
         [0027]     The control unit  34  guarantees the formation of the respectively required loop lengths between two separation operations, by way of the drive speed of the feed roller  30   a.  If a constant feed speed (v E =constant) is not selected, then the length l S2  of the loop  80  produced in the buffer unit corresponds to the integral over the speed profile v E =v E (t):  
         l   S2     =       ∫   0       t   E     -     Δ   ⁢           ⁢   t         ⁢         v   E     ⁡     (   t   )       ⁢           ⁢     ⅆ   t             
 
         [0028]     The desired decoupling effect can be satisfied by l S1 ≦l S2 .  
         [0029]     When applying a label E, first a printed segment of the label web  22  is fed to the separation unit  50  from the printing unit  40 . The segment of the label web  22  is passed by the feed roller  30   a  in the direction of the surface O to be labelled of the product P. Due to the self-adhesive property of the side  22   a  of the label web  22 , it remains adhering to the product P upon coming into contact with the surface O thereof. To ensure that the label web  22  adheres securely and without folds, it is pressed against the surface O of the product P by the pressure roller  60   a,  in the application unit  60 . From that moment on, the end of the label web  22  moves with the surface O of the product P at the conveyor speed v p . The control unit  34  for less than a time t E −Δt causes the feed roller  30   a  to operate at the feed speed v E =constant or, as discussed above, with a different speed profile v E =v E (t). More label web  22  thereby passes through the separation unit  50  than is applied to the surface O of the product P. The loop  80  of the buffer unit  70  is thereby formed with the required length. The length is preferably in the region downstream of the separation unit as far as the application unit  60 . In one embodiment, the control unit  34  can recognize, by means of a timer function, when the necessary loop length is attained. As soon as the required loop length is formed, the label web  22  is stopped for at least the duration of a separation operation Δt. Subsequently, separation of the label E is immediately implemented at the separation unit  50 . Tearing or damaging the labels E is therefore avoided.  
         [0030]     While the feed roller  30   a  is stopped, the application operation at the product P is continued by the label web  22  which is stored in the form of a previously formed loop  80 . The label web  22  can be stopped for separating a label E without stopping or decelerating the product or products P which is or are to be labelled.  
         [0031]     A further possible way of providing a buffer or a loop can be attained if the strip speed of the product P to be labelled is accelerated or slowed down, with the material web being advanced at the same speed at the same time.  
         [0032]     If three application devices are combined together in such a way that the respective pressure rollers are respectively oriented horizontally in relation to one of the three sides of the products, which are in orthogonal relationship with the plane defined by the pressure rollers of the application units, then different labels can be applied simultaneously to all three sides in one pass.  
         [0033]     In a time-controlled mode of operation between two separation operations, therefore, more label web can be moved past the separation unit than is applied to the product to be labelled. This affords a buffer which can be used up during the individual separation operations.  
         [0034]     The invention has been described with reference to various figures and embodiments, but is not limited thereto. It is expected that persons skilled in the art can and will design alternative embodiments that are within the scope of the invention, which is limited only by the appended claims.