Patent Publication Number: US-2010116408-A1

Title: Devices and methods for applying pressure-sensitive adhesive liner-less labels to articles

Description:
This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. Application Ser. No. 60/810,771, entitled Devices &amp; Methods for Applying Pressure-Sensitive Adhesive Liner-Less Labels to Articles, filed on Jun. 2, 2006. This prior provisional application is expressly incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to label applicators and more particularly, to label applicators and methods for applying pressure-sensitive adhesive liner-less labels to passing articles. 
     BACKGROUND OF THE INVENTION 
     Label applicators for applying pressure-sensitive adhesive-backed labels to articles passing the applicator on a conveyor are well known. Label applicators of this general type are shown in commonly assigned U.S. Pat. No. 4,255,220, issued to Kucheck et al., and U.S. Pat. No. 4,844,771, issued to 
     Crankshaw et al, for example. Other prior art references of interest include Published U.S. Patent Application No. 2003/0121593, U.S. Pat. No. 5,935,361 to Takahashi et al., U.S. Pat. No. 5,643,395 to Hinton, U.S. Pat. No. 5,039,374 to Winter, and Published U.S. Patent Application No. US 2003/0121593. All of the aforementioned patents and published patent applications are herein expressly incorporated by reference. Typically, such labeling apparatus comprise a supply of adhesive-backed labels carried upon an elongate web of release material which is fed from a supply reel to a take-up reel, with the label applicator disposed between the two reels. 
     In some applications, it is presently desired to utilize pressure-sensitive adhesive-backed labels which are not carried on such a web, in order to eliminate the need to dispose of the waste web collected on the take-up reel, once the labels thereon have been dispensed. In particular, it is becoming increasingly common for governments to impose punitive fees for disposing of waste generated during manufacturing processes, and there is also a cost savings if materials such as the carrier web can be eliminated. Accordingly, companies such as Catchpoint, Inc., having a U.S. office in Piscataway, N.J., have developed liner-less labels, which are described at its website, www.catchpointlabels.com. Such labels are also described, for example, in U.K. Patent Application No. 0501369.3, filed on Jan. 22, 2005 and entitled Improvements to Labels and Application Apparatus therefor, herein expressly incorporated by reference. 
     These new label types are not amenable to application using existing label applicator systems and processes. Accordingly, what is needed are new or modified systems and processes for efficiently and reliably separating and dispensing these types of labels. 
     SUMMARY 
     The present invention addresses the above identified problem by employing a coordinated drive roller and vacuum belt system for applying a distally directed tensile force (i.e. a tensile force applied in the same direction as the direction of travel of the label feedpath) at an appropriate time for separating the connected labels from one another reliably and without tearing the labels. This force is applied by determining when a label&#39;s leading edge passes the nip point of the drive roller and before the label sensor, which is disposed at a junction between the drive roller and the vacuum belt. At this moment, the drive roller is stopped, while the vacuum drive belt continues to advance, thus pulling the label in question distally, relative to its trailing label, which is stopped on the drive roller. This precision operation has been found to be simple and effective, and to reliably and accurately dispense labels of the type described for application on articles passing on an adjacent conveyor system. 
     More particularly, there is provided a label application system for applying pressure sensitive liner-less labels to passing articles, which comprises an unwind assembly adapted for carrying a roll of pressure sensitive liner-less labels and unwinding the labels into a label feedpath. The labels are connnected to one another end-to-end. The system further comprises a drive area, comprising a main drive roller and a nip roller assembly. The nip roller assembly comprises a nip roller, wherein the main drive roller and the nip roller are disposed so that the label feedpath feeds sequential connected labels between the main drive roller and the nip roller. A first stepper motor is provided for rotating the main drive roller. A vacuum drive belt is disposed downstream of the main drive roller, wherein the labels are advanced by the main drive roller onto the vacuum drive belt. A second stepper motor is provided for driving the vacuum drive belt. A processor functions to count the steps of the first stepper motor. 
     In preferred embodiments of the invention, there is a dancer arm on the unwind assembly for absorbing initial acceleration forces on the labels, in order to prevent premature label separation. 
     Operationally, the processor is adapted to stop the first stepper motor after a predetermined number of motor steps have been counted, so that continued operation of the second stepper motor functions to assist in separating adjacent ones of the labels as the labels are advanced onto the vacuum drive belt. A label sensor, disposed in the drive area, assists the processor in determining when to commence the counting step. The label sensor is adapted to sense when a leading edge of an advancing label reaches a predetermined point on the label feedpath, and to provide feedback to the processor. 
     Preferably, the nip roller assembly and the vacuum drive belt are oriented at approximately the same angle, so that an angle of orientation between the nip roller assembly and the vacuum drive belt is approximately zero. 
     In another aspect of the invention, there is provided a label application system for applying pressure sensitive liner-less labels to passing articles, which comprises a dispenser for dispensing a plurality of pressure sensitive liner-less labels into a label feedpath, wherein the labels are connected to one another end-to-end. A main drive roller is disposed along the label feedpath, and a vacuum drive belt is disposed downstream of the main drive roller. Thus, the connected labels are advanced by the main drive roller onto the vacuum drive belt. A first motor is provided for rotating the main drive roller, and a second motor is provided for driving the vacuum drive belt. A processor is provided for differentially driving the first and second motors, such that the second motor continues operating for a period of time after the first motor has been stopped, while one of the labels is advancing onto the vacuum drive belt. As a result of this differential operation, a tensile force is exerted on the label to separate it from its adjacent label. 
     Preferably, both the first and second motors comprise stepper motors. A counter is provided for counting the steps of the first motor during operation thereof. The processor is adapted to stop the first stepper motor after a predetermined number of motor steps have been counted, so that continued operation of the second motor functions to assist in separating adjacent ones of the labels as the labels are advanced onto the vacuum drive belt. 
     Additional features of the inventive system may include a dancer arm on the label dispenser for absorbing initial acceleration forces on the labels, in order to prevent premature label separation. A label sensor is provided, which is adapted to sense when a leading edge of an advancing label reaches a predetermined point on the label feedpath, and to provide feedback to the processor. 
     In still another aspect of the invention, there is disclosed a method of applying pressure sensitive liner-less labels to passing articles, which comprises a step of advancing a chain of adjacent, attached pressure sensitive liner-less labels along a label feedpath to a position adjacent to a main drive roller, driven by a first motor. The labels are further advanced, sequentially, onto a vacuum drive belt, which is driven by a second motor. A further step involves sensing when a leading edge of a label advances to a predetermined point on the label feedpath, in proximity to a junction between the main drive roller and the vacuum drive belt. The first motor is stopped after a predetermined period of time has passed from the time when the label leading edge was sensed. Since the second motor continues to operate, the leading edge of the label continues to advance along the vacuum drive belt, relative to the next label, which is stopped on the main drive roller, thereby exerting a force which separates the leading label from its adjacent label. 
     Preferably, the first motor comprises a stepper motor, and the stopping step discussed above comprises a step of starting a counter for counting first motor steps, and stopping the first motor after a predetermined number of motor steps have been counted. 
     The invention, together with additional features and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. In these accompanying drawings, like reference numerals designate like parts throughout the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a labeling system constructed in accordance with the principles of the present invention; 
         FIG. 2  is a top schematic view of the system shown in  FIG. 1 ; 
         FIG. 3  is a schematic view, from the right side, of the system shown in  FIGS. 1 and 2 ; 
         FIG. 4  is an enlarged schematic view of the drive area portion of the system shown in  FIGS. 1-3 ; 
         FIG. 5  is a schematic view, in isolation, of the main drive roller assembly; 
         FIG. 6  is a bottom view of the main drive roller assembly shown in  FIG. 5 ; 
         FIG. 7  is a top schematic view, in isolation, of the vacuum grid assembly; 
         FIG. 8  is a front view of the vacuum grid assembly shown in  FIG. 7 ; 
         FIG. 9  is a top schematic view, in isolation, of the nip roller drive assembly; 
         FIG. 10  is front view of the nip roller drive assembly shown in  FIG. 9 ; 
         FIG. 11  is side view of the nip roller drive assembly shown in  FIGS. 9 and 10 ; and 
         FIG. 12  is a schematic view illustrating a series of connected labels  14 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views and embodiments, there is shown in  FIGS. 1-3  a label applicator  10 . The label applicator  10  comprises an unwind assembly  12  on which is carried a roll of labels  14  for application to passing articles  16  on a conveyor  18 , which moves in a direction indicated by an arrow  20 . The unwind assembly  12  is comprised of an inner assembly unwind disk  22  ( FIG. 2 ) and an outer assembly unwind disk  24 . An assembly unwind block  26  supports the unwind assembly  12  on a housing  28 . The unwind assembly  12  is rotatably driven through an assembly unwind drive mechanism  30 , also supported on the assembly unwind block  26 , and an associated motor  31 . A dancer arm  32  is provided on the unwind assembly for absorbing initial acceleration of label movement, for purposes to be described more fully hereinbelow. 
     The labels  14  are preferably pressure sensitive adhesive labels which are of a recently available type manufactured and distributed, for example, by Catchpoint, Inc., as discussed above. Conventional pressure sensitive adhesive labels are labels which have been die cut on a release web or liner, which has a combination of face material and pressure sensitive adhesive applied to it. These labels are manufactured in rolls. As each label is dispensed, for application to an article, it is peeled off of the release liner and applied to the article. The primary purpose of the release liner is to carry the label to a dispense point, where the label is removed from the release liner. Once all of the labels are removed from the release liner, the liner, which has been again rolled up onto a second spool, is discarded. 
     In contrast, as shown particularly in  FIG. 12 , in the present invention, the labels  14  comprise a single web on which the labels  14  are printed at spaced intervals, wherein the labels comprise the entirety of the web, and are connected to one another end-to-end by full width transverse lines of weakness  33 , typically a micro-perforation. Each label  14  comprises a leading edge  14   a  and a trailing edge  14   b,  as shown. Thus, once the labels  14  have been dispensed, there is no remaining carrier web to dispose of, which is a substantial environmental advantage. As noted previously, such labels are described in detail, for example, in U.K. Patent Application No. 0501369.3. More information on some of the types of labels which may be suitable for use in the inventive system is available at www.catchpointlabels.com. 
     Labels  14  unwinding from the unwind assembly  12  are routed about idler rollers  34  ( FIG. 1 ) along a feedpath to a drive area  36 , which is more particularly shown in  FIG. 4 . The drive area  36  comprises a main drive roller  38  (illustrated in enlarged view in  FIGS. 5 and 6 ), a nip roller drive  40 , comprising a plurality of nip rollers  42 , and an assembly vacuum grid assembly  44 , which is more particularly shown in  FIGS. 7 and 8 . The label feedpath is directed between the main driver roller  38  and the nip rollers  42 , then onto the vacuum grid assembly  44 . The vacuum grid assembly comprises a plurality of vacuum fans  46  ( FIG. 2 ) disposed beneath a vacuum drive belt  47  for receiving and retaining labels  14  thereon, as will be described below. 
     Within a control box or enclosure  48  are disposed the electrical controls necessary to operate the system. Included therein is a drive roller stepper motor  50 , together with various components, such as brackets, pulleys, and gearbelts, for connecting the stepper motor  50  to the drive roller  38 . 
     The nip roller drive  40  is more particularly shown in  FIGS. 9-11 . In addition to the rollers  42 , there is disposed within the drive  40  a sensor block  52 , as shown. 
     In operation, an operator activates the label application system by actuation of an appropriate control switch on an operator control box  53 . Once operational, the labels  14  are unwound from a roll of labels disposed on the unwind assembly  12 . The dancer arm  32  functions to absorb initial acceleration of label movement, in order to keep the labels  14  from separating from one another prematurely. The labels pass along the illustrated label feedpath ( FIG. 1 ), about idlers  34 , until they arrive at the main drive area  36 . The main drive roller  38  is preferably silicone coated, and is powered by the stepper motor  50 . The feedpath carries the still-connected labels  14  between the drive roller  38  and a first nip roller  42  of the nip roller drive  40 . The nip roller drive  40  comprises a plurality of nip rollers  42  (two are shown), which are preferably plasma coated with a high release material. 
     The main drive assembly  36 , comprising the main drive roller  38  in combination with the nip roller drive  40 , functions to advance the labels  14  to the assembly vacuum grid  44 . In particular, the labels are advanced to the vacuum drive belt  47 , which is also powered by a stepper motor  54 . The labels are fed between the vacuum drive belt and a second nip roller  42 , and are retained on the vacuum drive belt  47  because of perforations in the belt, and continued operation of the underlying vacuum fans  46 . 
     Between the main driver roller assembly  36  and the vacuum drive assembly  44 , is the above described label sensor  52 . In the illustrated embodiment, the label sensor  52  is disposed on the nip roller assembly ( FIG. 9 ), between the two nip rollers  42 , so that it is located approximately at the junction between the main drive roller assembly  36  and the vacuum drive belt  47 . The label sensor  52  functions to sense the beginning and end of each label  14 . 
     The labels  14  are separated from one another during the transit between the main drive area  36  and the vacuum drive belt  47 . The separation process occurs as follows. First, both motors  50  and  54 , driving the drive roller  38  and vacuum drive belt  47 , respectively, are turned on at the same time. As each label leading edge passes the label sensor  52 , a processor in the control box  48  or operator control box  53  starts a counter for counting motor steps. When the proper number of motor steps occur, the processor stops the main drive motor  50 , but continues operating the vacuum belt drive motor  54 . The processor then monitors the label sensor, looking for the trailing edge of the label. Once the label trailing edge is sensed, the processor continues to run the motor  54  until the now separated label  14  reaches the end of the vacuum belt. The label is then dispensed onto a passing article  16 , in a conventional manner, over a distal peeling edge  56  on the belt  47 . 
     As illustrated in the drawings, it is preferably the case that the nip roller assembly is oriented at an angle similar to or equal to that at which the vacuum drive belt  47  is oriented. In other words, the preferred angle of orientation between the nip roller assembly and the vacuum drive belt is approximately zero. As is apparent from the above description, to those skilled in the art, the continued operation of the stepper motor  54 , after the stepper motor  50  ceases function, causes a distally directed tensile force to be applied to the label, because the vacuum drive belt  47  is continuing to move, while the main drive roller  38  is stopped. This applied tensile force is sufficient to tear the label  14  away from the label  14  connected thereto at its trailing edge  14   b,  at the aforementioned line of weakness  33 . The applied tensile force is sufficient to tear the microperforation  33 , but not enough to tear the label  14  itself. 
     While this invention has been described with respect to various specific examples and embodiments, it is to be understood that various modifications may be made without departing from the scope thereof. Therefore, the above description should not be construed as limiting the invention, but merely as an exemplification of preferred embodiments thereof and that the invention can be variously practiced within the scope of the following claims.