Patent Publication Number: US-7223030-B2

Title: Systems and methods for determining physical location of RFID tags on embedded print media

Description:
TECHNICAL FIELD 
   Specific embodiments relate to systems for determining the position of tags on media having one or more embedded pre-programmed radio frequency tags. More particularly, the invention relates to a system using a radio frequency reader for reading pre-programmed data from one or more radio frequency identification tags to determine the position of at least one tag on the print media. 
   BACKGROUND OF THE INVENTION 
   Inkjet and laser printers have become commonplace equipment in most workplace and home computing environments. Today, many printers are multi-functional assemblies capable of printing on a large array of print media including letterhead, paper envelopes and labels. A recent innovation in the printing industry involves the manufacturing of print media with embedded radio frequency signatures in the form of Radio Frequency Identification (RFID) transponders or tags. These tags, sometimes called “Smart Labels”, may be used with a variety of existing printing methods. 
   Embedded print media generally comprises a backing material (sometimes referred to as the “web”) upon which a label is applied, with a RFID tag sandwiched in between the label and the backing material. There may be one or more labels on the web and the sheet, as presented, may be part label and part plain paper. In some cases, there may be more than one tag arrayed across the width and down the length of the media such that multiple columns and/or rows of tags are contained on the print media. 
   Another similar type of embedded print media is known as “Smart Paper” in which RFID tags are embedded into the media without labels. One application for Smart Paper is in the area of secure document storage where access to information printed on a document is controlled by use of data control mechanisms such as Access Control List (“ACL”) embedded in a tag on the media. To control access, a radio frequency reader/programmer situated near a control point, such as an access control cabinet, can check the ID of a user wanting to access the cabinet against the ACL on the tag on the media. If the ID of the user and the ACL do not match, an alarm can be invoked to notify of an attempted breach in security. In addition, the information on the ACL can be spread among a plurality of tags on a single sheet of print media to accommodate multiple accesses by multiple users while saving media costs. 
   One of the benefits of printing labels on a cut-sheet printer such as a laser or inkjet printer is that the relatively wide format allows for multiple columns of labels to be used. The use of multiple columns improves the overall rate at which the labels can be printed. At the same time, because the customer can print more than one label for each sheet printed, the relative cost of each label is greatly reduced. 
   Accordingly, printing of on media with embedded RFID tags is rapidly becoming a growing area of label printing. Each tag on a sheet can be printed with certain data, and the RFID tag embedded within that media can be used to allow individualized processing of user associated data. For example, a shipping label might have the delivery address and a package tracking ID printed on it, while the corresponding tag would be programmed with the same information. The delivery information can then be read from the tag, whether or not the package is positioned so that the tag is visible. 
   It is desirable that the same efficiencies found in multi-label sheets of traditional label media be realized in RFID embedded media. The problem this presents is the need to correlate the printed data on the sheet with the data programmed into each tag. As such, a means of locating each tag&#39;s physical position on the sheet during the printing and programming process in order to ensure that the correct data is programmed into each tag would provide numerous advantages. 

   
     BRIEF DESCRIPTIONS OF THE DRAWINGS 
     The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements, and in which: 
       FIG. 1  shows a system for determining the position of labels on media having one or more embedded pre-programmed radio frequency devices according to one embodiment of the invention; 
       FIG. 2  shows a sheet of print media containing a plurality of radio frequency devices which store position data; 
       FIGS. 3   a – 3   c  illustrate various relative position encoding schemes which can be used to determine the position of labels on print media having embedded radio frequency devices according to one embodiment of the invention; 
       FIG. 4  is a process flow diagram showing a method of determining the position of labels on media having one or more embedded radio frequency devices according to one embodiment of the invention; and 
       FIG. 5  is a simplified architectural block diagram of a label printing system for determining the position of labels on media having or more embedded pre-programmed radio frequency devices according to one embodiment of the invention. 
   

   DETAILED DESCRIPTION 
   Referring now to the drawings and more particularly to  FIG. 1 , therein is shown a system  10  for determining the position of labels on print media embedded with pre-programmed radio frequency data storage devices, such as RFID tags, contained on a cut sheet of print media according to one embodiment of the present invention. System  10  may include a printer assembly  14  such as, for example, an ink jet or laser printer or other image forming platform. For convenience, system  10  will be described in connection with an ink jet printer although it should be understood the system  10  of the invention may be implemented in other image forming platforms such as a laser or dye diffusion printer, for example. 
   Host  12  may be communicatively coupled to printer assembly  14  by way of communications link  16  and may include one or more end-user applications capable of generating a print request. Communications link  16  may be established by, for example, a direct connection, such as a cable connection, between printer assembly  14  and host  12 ; by a wireless connection; or by a network connection, such as for example, an Ethernet local area network (LAN) or a wireless networking standard, such as IEEE 802.11. Although not shown, host  12  may include a display, an input device such as a keyboard, a processor and associated memory. Resident in the memory of host  12  may be printer driver software which places print data and print commands in a format that can be recognized by printer assembly  14 . The format can be, for example, a print data stream that includes print data and printing commands for a given print request and may include a print header that identifies scan data. The printer driver software may also include print media information such as, for example, media type and size. In addition, such print media information may include the known fixed position locations of radio frequency data storage devices, such as a plurality of RFID tags, which have been placed on or embedded in the print media as “Smart” labels or other similar cut-sheet print media. In this regard, for determining the location of labels on print media, the print data stream may include at least two types of data: print data to be used by the print engine and radio frequency data to be programmed into the radio frequency based data storage devices such as RFID tags, for example. 
     FIG. 1  shows that printer assembly  14  includes a printhead carrier system  18 , a print media feed system  20 , a mid-frame  22 , a master controller  24 , a print media source  25  and an exit tray  26 . Print media source  25  is configured and arranged to supply individual sheets of print media  28  to print media feed system  20  which, in turn, further transports sheets of print media  28  during a printing operation. 
   Printhead carrier system  18  includes a printhead carrier  30  which may carry, for example, a color printhead  32  and black printhead  34 . A color ink reservoir  36  is provided in fluid communication with color printhead  32  and a black ink reservoir  38  is provided in fluid communication with black printhead  34 . Reservoirs  36 ,  38  may be located near respective printheads  32  and  34 , which in turn may be assembled as respective unitary cartridges. Alternatively, reservoirs  36 ,  38  may be located remote from printheads  32 ,  34 , e.g., off-carrier, and reservoirs  36 ,  38  may be fluidly interconnected to printheads  32 ,  34 , respectively, by fluid conduits. Printhead carrier system  18  and printheads  32  and  34  may be configured for unidirectional printing or bi-directional printing. 
   Printhead carrier  30  is guided by a pair of guide rods  40 . Alternatively, one of guide rods  40  could be a guide rail made of a flat material, such as metal. The axes  40   a  of guide rods  40  define a bi-directional-scanning path, also referred to as  40   a , of printhead carrier  30 . Printhead carrier  30  is connected to a carrier transport belt  42  that is driven by a carrier motor  44  by way of a driven carrier pulley  46 . Carrier motor  44  has a rotating carrier motor shaft  48  that is attached to carrier pulley  46 . Carrier motor  44  is electrically connected to print controller  24  via communications link  50 . At a directive of print controller  24 , printhead carrier  30  is transported, in a reciprocating manner, along guide rods  40 . Carrier motor  44  can be, for example, a direct current motor or a stepper motor. 
   The reciprocation of printhead carrier  30  transports ink jet printheads  32  and  34  across the sheet of print media  28  along bidirectional scanning path  40   a  to define a print area  52  of printer assembly  14  as a rectangular region. This reciprocation occurs in a scan direction  54  that is parallel with bidirectional scanning path  40   a  and is also commonly referred to as the horizontal scanning direction. Printheads  32  and  34  are electrically connected to print controller  24  via communications link  56 . 
   During each printing pass, i.e., scan, of printhead carrier  30 , while ejecting ink from printheads  32  and/or  34 , the sheet of print media  28  is held stationary by print media feed system  20 . Before ink ejection begins for a subsequent pass, print media feed system  20  conveys the sheet of print media  28  in an incremental, i.e., indexed, fashion to advance the sheet of print media  28  into print area  52 . Following printing, the printed sheet of print media  28  is delivered to print media exit tray  26 . Print media feed system  20  includes a drive unit  58  coupled to a sheet handling unit  60 . Drive unit  58  is electrically connected to print controller  24  via communications link  62 , and provides a rotational force which is supplied to sheet handling unit  60 . 
   As such, printer assembly  14  provides a print media pathway, represented by arrow  110 , for the transport of print media  28  from a paper source  25  to a designated print area  52 . Printer assembly  14  may include a print media sensor  86  capable of detecting when print media  28  has reached a predetermined point along the print media pathway  110 . Print media sensor  86  may be configured to detect the leading edge of the print media  28  as it is conveyed by the print media feed system  20  through the printer assembly  14 . In addition to, or alternatively, the print media sensor  86  may detect the trailing edge of the print media  28 . In this regard, the leading edge of the print media  28  is defined as the media edge which enters the printing device&#39;s print area  52  first and the trailing edge is equivalently to that edge which enters the print area  52  last. 
   The invention has particular application and provides particular advantages in the context of modern day image forming devices, such as printer assembly  14  and other commercially available types of printer platforms, where print media, such as print media  28 , contains multiple radio frequency data storage devices, such as RFID tags, to which data can be written using one or more data programmers, such as an RFID reader/programmer with one or more antennas, for writing data to the radio frequency data storage devices. Such RFID reader/programmers are readily available and their details of operation and use are known to those of ordinary skill. The use of such reader/programmers to determine the position of such devices which are embedded on print media, however, is unique, novel and non-obvious. 
   Referring to  FIG. 2  therein is shown a cut sheet of print media  28  having a plurality of labels  89  and a plurality of pre-programmed radio frequency tags  88 . The specific configuration of print media  28  shown uses a radio frequency tag  88  for each label  89 . It should be understood, however, that more or less tags may be employed for each label and that other configurations of the print media  28  may be utilized. Also, it should be understood the invention can apply equally as well to print media having no labels such as is the case with media known as Smart Paper wherein the tags  88  are inserted into the print media without labels. In either case, the pre-programmed radio frequency tags  88  typically comprise RFID tags having memory for storing a variety of data. In one embodiment, each tag  88  (the terms “tag” and “tags” shall be used interchangeably) may be programmed to contain user specific information such as, for example, the address and identification of an intended recipient, order number, date of shipment and other types of label specific data. In addition, each tag may be pre-programmed with a unique serial number that allows each tag to be identified. Typically, the serial number would be programmed by the tag manufacturer and the tag  88  would be inserted into a label  89  (or directly on the print media  28  in the case of Smart Paper) in a known, fixed sequence. In this way, the physical location of a tag  88  on a page of print media  28  is fixed and will not change until a label  89  is removed. Thus, during manufacture of the print media  28 , an RFID reader/programmer may be used to pre-program each tag  88  with data indicating its relative position on the page of print media  28  based upon a known fixed position for each application. 
   As shown, labels  89  and pre-programmed radio frequency tags  88  are arranged into rows and columns. It should be understood, however, that other positions and configurations of the labels  89  and tags  88  may be employed and that more or less columns and rows may exist according to various media configurations. Further, it should be understood the use of labels  89  for purposes of the invention is optional as would be the case where tags  88  are directly inserted on the media without labels. 
   Arrow  140  indicates the direction of travel of media  28  along a print media pathway such as print media pathway  110 . As discussed above, one or more sensors arranged about a printer&#39;s print media pathway  110  may be used to determine and track the location of print media  28  as it passes through the printer&#39;s print area, such as print area  52 . Such sensors may be arranged to “make” at the leading edge of a sheet of print media and “break” at the trailing edge, providing a master controller, such as master controller  24 , with an indication of the location of the print media  28  at any given point along the printer&#39;s print media pathway  110 . For this purpose, printer assembly  14  may include a second print media sensor  90  which functions like first print media sensor  86 . In either configuration, i.e. one or two print media sensors, a communications link  92  is provided between the print media sensor  86  and the master controller  24 . 
   Communications link  92  provides a means for print media sensor  86  to signal master controller  24  and thereby notify master controller  24  that a sheet of print media, such as print media  28 , has been detected. A similar communications link (not shown) may be provided coupling the second print media sensor  90  to the master controller  24 . In this way, the master controller  24  will know when the leading edge and/or trailing edge of the print media  28  traverses the print area  52  and/or a predetermined point along the print media pathway  110 . 
   Thus, a plurality of pre-programmed radio frequency tags  88  have been placed on or embedded in print media  28  at specific locations and data stored on tags  88  can be used to determine the relative position of the tags  88  on the page of print media  28 . A radio frequency data programming device  94 , such as an RFID reader/programmer, may be placed about the printer assembly  14  in an area where it can write data to the pre-programmed radio frequency tags  88  using known techniques. In practice, write operations may commence once print media  28  has reached a predetermined point along the print media pathway  110 . 
   Since pre-programmed radio frequency tags  88  are contained on print media  28 , a radio frequency data programming device  94  can be used to write data to and read data from radio frequency tags  88  using antenna  144 . While a single antenna  144  is shown, multiple antennas may be used across the horizontal axis of the print media pathway  110  so that their positions roughly correspond to known or expected positions of the columns of radio frequency data storage devices. As print media passes within range of antenna  144 , data can be written to or read from each of the tags  88 . 
   Master controller  24  of print assembly  14  may confirm if pre-programmed radio frequency tags  88  contained on print media  28  are positioned as expected on print media  28 . As such, master controller  24  provides the necessary process logic for reading position data from the tags  88  and for comparing the read position data with position data obtained in a print data stream received from an end-user application. Communications link  100  coupling radio frequency data programming device  94  to master controller  24  may provide a signal pathway for this purpose. 
   Thus, in one embodiment, the present invention provides a system that uses a printing subsystem, such as printer assembly  14 , and a radio frequency reader, such as radio frequency data programming device  94  having a radio frequency antenna  144 , for reading pre-programmed data from the radio frequency tags  88  in order to determine the relative position of the tags  88  on the print media  28 . The system reads the information contained on tags  88  on the page of print media  28  and extracts from each tag  88  its position indicating data. During printing, the printing subsystem may receive a print data stream from a user application operating on a user platform, such as host  12 . The print data stream for each page may include two types of data: print data to be used by the print engine of the printing subsystem, and RFID data to be programmed into the tags  88 . Each piece of RFID data may also include an indication of tag position on the page of print media  28  that corresponds to the data pre-programmed into exactly one of the tags  88  on the page. The printing system can match the pre-programmed position data from the tags  88  with the position data in the print data stream to determine which data to program into each tag  88 . The data to be programmed into the tag  88  may overwrite the pre-programmed position data, or can be appended after the position data, as required by the end-user application. 
   There are several possible schemes for encoding relative position into the tags. Each has different strengths, and may be more or less useful in a particular application.  FIGS. 3   a  thru  3   c  illustrate a few potential examples for a relative position encoding scheme that may be used in order to indicate the relative position of a label on a sheet of print media. It should be understood that the examples of  FIGS. 3   a – 3   c  serve only to illustrate the invention, but should not be understood to limit its application. The data chosen to be pre-programmed into the tags is not important, only that the data is also known to the application and therefore may be used to key end-user tag data to a specific tag  88  with respect to its position on the page on print media  28 . 
     FIG. 3   a  shows that position data may be encoded on each tag  88  with the X/Y position in physical units (e.g. inches or mm) of a known tag feature (e.g. center, a corner, or the chip position) from a known feature on the sheet (e.g. a given corner) of print media  28 . This may have the advantage of providing increased precision in locating randomly placed tags. 
     FIG. 3   b  illustrates another example of a relative position encoding scheme that is useful where tags  88  are uniformly distributed over the area of the print media  28  (say, an array of 3 across by 8 down). With the encoding scheme of  FIG. 3   b,  an array index is assigned to each tag  88  indicating its position relative to the other tags  88 . For example, the upper-left corner tag in an 3×8 array would be encoded with (1, 1), and the tag immediately below it would be encoded with (1, 2). The lower-right corner tag would be encoded with (3, 8). 
   A third example for a relative position encoding scheme is shown in  FIG. 3   c , which involves the simple assignment of a sequence number to the tags  88 . This sequence can be in any order with respect to the tags&#39; actual physical location, so long as the sequence is both known and fixed. For example, a sheet with six tags would have each tag encoded with a number from 1 to 6 in some known order. It may also be helpful to encode each tag with the total number of tags on the sheet (“2 of 6” rather than simply “2”). A variant on this scheme is to require the tags  88  to be placed in increasing serial number order. The serial numbers need not be consecutive, so long as they are placed in a known order. 
   In each of these cases, the numbering scheme and sequence of the tags  88  for the print media  28  is known to the end-user application. The data to be programmed into each tag  88  may be assigned a position using the same scheme as the label media, and the printing subsystem need only match the position information in the data stream with the position information in the tags  88  to program the correct data in each tag  88 . 
     FIG. 4  is a process flow diagram showing a method, denoted generally as  200 , of determining the position of tags on media having one or more embedded radio frequency devices. Method  200  begins at step  202  wherein each tag is programmed with a serial number that allows a radio frequency reader/programmer to uniquely identify each tag. Preferably, this is accomplished during manufacture of the tags or the print media. Next, at step  204 , the tags are embedded into the print media, such as print media  28 , in a known fixed sequence. Step  204  may involve placing tags on labels which in turn are inserted on the print media for creating Smart Labels. In either case, at this point the physical location of the tags  88  on the print media will not change unless, in the case of Smart Labels, a label is removed from the web at application. 
   During manufacture process, the tag insertion equipment may then program each tag with relative position data, step  206 , based on the known fixed position of the tags on the print media. At some point the print media is inserted into the printing subsystem, step  208 , and a print request is transmitted to the printing subsystem, step  210 . The print request may take the form of a print data stream for each page of print media on which data is to be printed. The print data stream may include two types of data: print data to be used by the print engine, and RFID data to be programmed into the tags  88 . In addition, each piece of RFID data may also include an indication of the position on the page that corresponds to the data pre-programmed into one of the tags on the page of print media. 
   At step  212 , a determination is made if the received print data stream contains position data. If not, process flow is directed to step  222  wherein the print request is denied or printing occurs without position data. However, if the data stream does contain position data, process flow to step  214  wherein the data stream is parsed into its constituent components in order to obtain the position data of the tags to be printed. Next, at step  216  the tags are read in order to obtain the pre-programmed position data contained on the radio frequency data storage devices, such as tags  88 . This permits a comparison of the position data contained in the print data stream with the position data pre-programmed in the tags  88 . Once the match is accomplished, data can be written, step  220 , at the correct positions. The data to be programmed into a particular tag can be written over the pre-programmed position data to conserve memory space on the device or the data can be appended after the position as determined by the end user application. 
   Having described the details of a system for determining the position of tags on print media having radio frequency data storage devices embedded therein,  FIG. 5  illustrates the essential components of such a system in simplified block diagram form. Specifically,  FIG. 5  shows a system  250  having a printing subsystem  255  that may include many of the operational components of a typical printer assembly, such as printer assembly  14 . The printing subsystem  255  includes a printer housing  257  in which a print engine  259  resides. Printing subsystem  255  also has memory  261  for storing data indicating the position of tags on media. The contents of memory  261  can be obtained from an end-user application  270  which may supply the position data to the printing subsystem  255  in a print data stream. 
   The printer housing  257  includes an opening  263  into which the print media  88  may be fed into the printing subsystem  255  for printing on the print media  28 . As the media  28  is fed into the printing subsystem  255 , a radio frequency reader  265  reads the data pre-programmed into the tags on the media  28 . Antenna  267  is provided for this purpose. In this way, the reader  265  reads pre-programmed position data from the radio frequency tags, such as tags  88 , and the printing subsystem  255  compares the pre-programmed position data with position data contained in a print request data stream to determine the position of at least one label on the print media  28 . Thus, the invention utilizes the ability to pre-program the tags with their location, and then read that data in the printer system  250 , to solve the problem of correlating the data to be printed on the print media with the data to be programmed into one or more tag on the media. 
   It should be understood that modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.