RFID printer and antennas

#A related U.S. patent application is co-owned application Ser. No. 11/789,109, filed Apr. 23, 2007 (now U.S. Pat. No. 7,439,861).

#1. Field

#The embodiments relate to RFID (Radio Frequency Identification) printers and antennas.

#FIG. 1 is a sectional view of an RFID printer;

#FIG. 2 is a perspective view of a roll of a web of labels containing RFID transponders;

#FIG. 3 is an enlarged sectional view showing components of the printer including an antenna system used to write to and/or read an RFID transponder in a label of a web of labels;

#With reference initially to FIG. 1, there is shown a printer generally indicated at 40 which is essentially the same as the printer 40 disclosed in U.S. Pat. No. 5,833,377, the disclosure of which is incorporated herein by reference, except as otherwise disclosed herein. For components in this application which correspond to components in U.S. Pat. No. 5,833,377 the same reference characters are used.

#While the invention is illustrated in connection with a thermal printer using dot heating elements to create images such as bar codes, graphics, alpha numeric characters and the like, the invention is also useful with printers such as ink jet, laser, xerographic, impact, and other types of printers.

#The printer 40 has a generally vertical frame panel 71 and a conductive metal horizontal frame member 72 on a conductive metal base plate 120. A movable mounting member 56 is pivotally mounted to the frame plate 71 about hinge blocks 73 (only one of which is shown in FIG. 1). A roll mounting member 50 is shown to mount a roll R of a web C of record members RM. The record members RM are illustrated to comprise a composite label web C which comprises a carrier web W to which a series of pressure sensitive labels L are releasably adhered by pressure sensitive, tacky, adhesive A (FIG. 2). If desired, the web of record members RM can be comprised of a web of tags or forms. The web C is shown to be paid out of the roll R and passes beneath a guide roller 62′ rotatably mounted by a bracket 62″ to a guide member 60 which is part of a web guide generally indicated at 62. Any suitable web guide, for example, just a member with a curved surface or a roller can be used instead, if desired. From there the web C passes between a thermal print head 69 which is part of a print head assembly 70 and a platen roll 63. It is noted the web C extends from the roll R to a position upstream of the nip of the print head 69 and the platen roll 63 and extends downstream beyond the nip. The platen roll 63 is shown to have a conductive metal shaft 506 about which a tubular elastomeric sleeve 506′ is received as shown in FIG. 3 for example. The shaft 506 acts as an RF reflector. If desired the shaft 506 can be made of a rigid plastics material which is not RF reflective. A delaminator in the form of a peel bar 64′ is provided downstream and preferably adjacent the nip. However, the delaminator can alternatively comprise a peel roller. A label L can be delaminated at the delaminator 64′ when the web W is advanced by a motor 165 between a motor-driven roll 65 and a back-up roll 66. A spring 66′ is used to urge the backup roll 66 toward the roll 65 so that the web W is pressed between the rolls 65 and 66. From there the carrier web W passes about an arcuate guide plate 170 and through an exit opening 49 of a movable panel 48.