US 6,3'
1
PROFILE CORRECTED LABEL WITH RFID
TRANSPONDER AND METHOD FOR
MAKING SAME
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to labels, such as pressure sensitive labels, which contain an RFID transponder as part of the label. In particular, the invention pertains to printable labels which may be attached to an item using pressure sensitive adhesives. Images may be printed on the labels using thermal printers which rely on heat and/or pressure to create the image, such as direct thermal or thermal transfer printers. The label containing an RFID transponder may be known as a smart label.
2. Description of the Related Art
In the past, smart labels containing an RFID transponder presented many problems relating to printing on the label. The generally uneven profile of an RFID transponder, when inserted into a label by positioning the RFID within layers of the label, results in physically supported areas and unsupported areas of the face sheet of the label. The face sheet is, as a result, uneven in its profile. Previously, the use of standard paper and film materials in the construction of a smart label resulted in a non-uniform surface profile for printing. Because of this uneven profile, when attempting to print on the label utilizing a direct thermal process or a thermal transfer process, uneven images are created on the printable surface. The profile presented by the RFID chip embedded in the smart label created print voids or uneven image density because of pressure gradients as the transponder section of the label passes under the thermal print head. This circumstance can create critical problems on printed labels, in particular on bar code labels where the bar code image must be uniform enough to be scanned by an optical scanner. If the face sheet was impossible to print on because of the uneven profile, it would be necessary in the past to attempt to print around the RFID transponder contained in the label. This creates problems in printing, because in order to avoid the RFID transponder, the printer would have to avoid the transponder during the printing process, which involves identifying the exact location of the transponder prior to printing, and then controlling the printer to print around the transponder.
Another problem in prior labels is that in some applications, such as when security is a concern, it is necessary to mask the presence of an RFID transponder in a label. Prior art materials used in the construction of smart labels did not effectively mask the existence of an RFID transponder in the label. This defeats the goal of maintaining the security or the anti-counterfeiting capacity of the label.
The uneven profile printability and security problems are overcome by the present invention.
SUMMARY OF THE INVENTION
The present invention presents a label containing an RFID transponder having a more uniform profile for printing, and also for concealment of the presence of an RFID transponder within the label. The invention teaches a new structure and method for reducing the uneven profile of a label containing an RFID transponder by utilizing a unique face sheet or face sheets which minimize the difference between unsupported and supported areas along the printable surface of the label.
It is an object of the invention to present a label containing an RFID transponder having a uniform surface profile for printing.
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It is a further object of the invention to present a label having a uniform profile for concealment of the presence of an RFID transponder in a label.
It is a further object of the invention to present a label 5 having a face sheet with a relatively high density and stiffness to reduce deformation and bending in the face sheet so as to not conform unevenly to the shape of the RFID transponder.
These and other objects of the invention will be realized
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by the structure and method set out below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectioned side view of a prior art label 15 containing an RFID transponder.
FIG. 2 is a sectioned side view of one embodiment of the present invention utilizing a liner.
FIG. 3 is a sectioned side view of a further embodiment of the present invention utilizing a liner. 20 FIG. 4 is a sectioned side view of a further embodiment of a linerless version of the present invention.
FIG. 5 is a sectioned side view of a further embodiment of a linerless version of the present invention.
25 DETAILED DESCRIPTION OF INVENTION
As shown on a prior art FIG. 1, past smart labels containing RFID transponders presented an uneven profile for printing on a face sheet. As seen, the presence of the RFID
30 transponder creates distinct supported and unsupported areas of the face sheet, which in turn results in a surface poorly suited for receiving a uniform image created by a thermal printer.
FIG. 2 illustrates a smart label according to the present
35 invention. An RFID transponder 1 is positioned between a liner layer 2 on one side of the RFID transponder 1 an adhesive layer 3 and face sheet 9 on the opposite side of the RFID transponder 1, and from the liner layer 2. The adhesive layer 3 may in one embodiment be thicker in dimension
40 from the prior art adhesive layers. In particular, the first face sheet 9 has a significantly increased thickness and/or rigidity as compared to prior art face sheets. The present invention may also utilize a bending beam construction in one embodiment which results in decreased pressure differences across
45 the surface of the printable face sheet. The RFID transponder may therefore be placed virtually anywhere on the label without effecting the ability to print an image at any point along the surface of the label. A more rigid face sheet results in a more consistent and uniform distribution of head
50 pressure from the printer. This minimizes pressure differences and vastly improves the print quality. The first face sheet 9 of the present invention may be made of a higher density and/or higher stiffness material as compared to prior art polypropylene or other materials. This eliminates the
55 excessive flexibility and lack of stiffness which would otherwise undermine the ability to present a uniform profile for printing. The thicker and/or less flexible first face sheet 9 does not conform readily to the shape of the RFID transponder in the label, and therefore presents a more
go uniform surface for printing.
FIG. 3 illustrates a smart label according to the present invention having an RFID transponder positioned between a liner 2 and an adhesive layer 3. A first face sheet 9 may be disposed generally over the adhesive layer 3. A second face
65 sheet 10 may be positioned over the first face sheet 9. In this embodiment, the second face sheet 10 may be of a standard flexible thermal paper stock, but the first face sheet layer 9
