Patent Publication Number: US-2007120942-A1

Title: Dual-sided two color thermal printing

Description:
BACKGROUND  
      Duplex or dual-sided direct thermal printing of transaction documents or receipts is described in U.S. Pat. Nos. 6,784,906 and 6,759,366. The printers are configured to allow printing on both sides of thermal media moving along a feed path through the printer. In such printers a direct thermal print head is disposed on each side of the media feed path. A thermal print head faces an opposing platen across the feed path from the print head.  
      In direct thermal printing, a print head selectively applies heat to paper or other sheet media comprising a substrate with a thermally sensitive coating. The coating changes color when heat is applied, by which “printing” is provided on the coated substrate. For dual-sided direct thermal printing, the sheet media substrate may be coated on both sides.  
      Duplex or dual-sided direct thermal printing has been described for providing variable information on both sides of a paper receipt, to save materials and to provide flexibility in providing information to customers. The printing can be driven electronically or by computer using a computer application program which directs dual-sided printing. A dual-sided direct thermal printer can also be configured for use in conjunction with simplex mode programs for printing of receipts or other documents.  
      It is known to provide temperature sensitive coatings using two or more dyes for direct thermal printing to be carried out in different colors on one side of the printing media. However direct thermal printing in different colors on opposite sides of the media may be useful in order to call attention to a particular side of the media being printed.  
     SUMMARY  
      A temperature sensitive recording material for two-sided direct thermal printing thereon is described. The material comprises an opaque substrate such as paper having temperature sensitive coatings on opposite sides of the substrate. The coatings change to colors different from one another when heated, so that direct thermal printing on opposite sides of the substrate is in different colors. The material may be in the form of a paper document such as a transaction receipt on which direct thermal printing on the front side is all in one color and direct thermal printing on the reverse side is all in a different color. The color of direct printing on one side of the document may designate the side that is printed. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  shows a schematic of a dual-sided imaging direct thermal printer useable for dual-sided, single pass printing of thermal media such as transaction receipts or tickets.  
       FIG. 2A  shows a receipt with transaction detail printed on the front side.  
       FIG. 2B  shows a receipt with supplemental information printed on the reverse side, such as variable stored information determined at the time of the transaction.  
       FIG. 3A  shows a two-sided receipt with a portion of the associated transaction detail printed on the front side of the receipt.  
       FIG. 3B  shows the reverse side of the receipt shown in  FIG. 3A  on which the remaining portion of the associated transaction data is printed. 
    
    
     DETAILED DESCRIPTION  
      By way of example, various embodiments of the invention are described in the material to follow with reference to the included drawings. Variations may be adopted.  
       FIG. 1  shows a schematic of a dual-sided imaging direct thermal printer  10  useable for dual-sided, single pass printing of transaction receipts or tickets at time of issue. The printer  10  operates on print media  20  which is double-sided thermal paper comprising an opaque substrate, preferably a cellulosic or polymer substrate sheet coated on each side with heat sensitive dyes as described in U.S. Pat. Nos. 6,784,906 and 6,759,366. Two-color printing capability is provided for two-sided direct thermal printing on opposite sides of the receipt by using a different colored dye on each side. Substrates and heat sensitive color changing coatings for direct thermal printing media are generally well known in the art. Dual-sided direct thermal printing can be facilitated by a media  20  which includes differently colored dyes on opposite sides of the media  20 , and a sufficiently thermally resistant substrate that inhibits direct thermal printing on one side of the media  20  from affecting coloration on the opposite side of the media  20 .  
      The thermal print media  20  may be supplied in the form of a paper roll or sheet, e.g., to provide a voucher, coupon, receipt, ticket or other article or document, upon which printing such as graphics or text, or both, may be printed on both sides of the media  20 .  
      As shown in  FIG. 1 , the printer  10  has rotating platens  30  and  40  and opposing thermal print heads  50  and  60  on opposite sides of the printed thermal media  20 . Dual-sided direct thermal printing of the media  20  occurs in a single pass at the time of the transaction or when a receipt or ticket is issued. The media  20  can be cut or severed to provide an individual receipt or ticket document, typically once printing is completed.  
       FIG. 2A  shows transaction detail  70  such as issuer identification, time, date, line item entries and a transaction total printed on the front side of a receipt  80 .  FIG. 2B  shows custom information  90 , e.g., based on recipient identity or transaction detail ascertained at transaction time, printed on the reverse side of the receipt  80 . For example, custom information  90  could include further or duplicate transaction information, a coupon as shown, rebate or contest information, serialized cartoons, conditions of sale, document images, advertisements, security features, ticket information, or other information, e.g., custom information based on recipient identity or transaction data or detail.  
      Dual-sided imaging direct thermal printer  10  is configured to allow printing on both sides of a receipt or other sheet media  20  moving along a feed path  25  through the printer  10  with print heads  50  and  60  on opposite sides of the media feed path  25 . Print heads  50  and  60  preferably have associated opposing platens  30  and  40  as shown.  
      A portion, e.g., half, of a block of data to be printed may be printed by direct thermal printing on one side of the media  20 , and another portion of the data, e.g., half, may be printed by direct thermal printing on the reverse side of the media  20 , or the media sides on which the respective portions of data are printed may be reversed. In this manner a transaction receipt may be generated in which a portion of the associated transaction data is printed on one side of the receipt and the remaining portion of the transaction data is printed on the other side of the receipt, conserving upon the amount of media  20  required for printing of the receipt. A dual-sided direct thermal printing function may be further be used to determine the portion or quantity of data, or a block of data, to be printed on a side of the media  20 . Different blocks of data may be alternatively selected for printing.  
       FIG. 3A  shows a two-sided receipt  100  with a portion of the associated transaction detail printed on the front side  110  of the receipt  100 .  FIG. 3B  shows the reverse side  120  of the receipt  100  shown in  FIG. 3A , where the remaining portion of the associated transaction data is shown printed on the reverse side  120  of the receipt  100 . Indicia such as “Front Side,” Reverse Side, “Side 1,” “Side 2,” or the like may be included on the two sides of the receipt  100  as shown to denote the two-sided nature of the receipt  100  or the respective side of the receipt  100  being viewed. Identifying indicia such as a receipt or transaction number, terminal number, store identifier, date, time or the like may be printed on both sides of the receipt to enable association of copied images of the two sides.  
      A dual-sided imaging direct thermal printer  10  having pre-print data storage facilities may store one or more blocks of data to be repetitively printed on a side of the media  20 , e.g., with data submitted by application software to be printed on the other media side. Where multiple data blocks are stored in the printer storage, the blocks may be alternatively selected for printing, as may be the media printing side selection.  
      The media  20  is a temperature sensitive recording material for two-sided, two-color direct thermal printing in a different color on opposite sides of the material. The media  30  comprises an opaque substrate having temperature sensitive coatings on opposite sides of the substrate. The coatings change to colors different from one another when heated, so that direct thermal printing on one side of the substrate is in a color different than the color of direct thermal printing on the other side of the substrate. The substrate preferably has a sufficient thermal resistance to prevent heat applied to one side of the media  20  from activating a color change on the opposite side of the media  20 .  
      The media  20  may use a primer material disposed beneath the temperature sensitive coatings on the opposite sides of the opaque substrate to adhere the coatings. The primer material may render the substrate opaque if not already opaque. The coatings may be disposed between the primer material and a protective top coat material.  
      By using a dual-sided, two-color direct thermal imaging material for the media  20  with a first temperature sensitive coating on the front side of the substrate, and a second temperature sensitive coating on the reverse side of the substrate, the first coating changes to a first color when heated and the second coating changes to a second color different from the first color when heated, so that direct thermal printing on the front side of the substrate is in a color different than the color of direct thermal printing on the reverse side of the substrate. The media  20  may thus be deployed to create a document printed by two-sided direct thermal printing on which direct thermal printing on the front side of the document is in one color and direct thermal printing on the reverse side of the document is in a different color, whereby the color of direct thermal printing designates the side of the document that is printed. For example, direct thermal printing on the front side of a receipt may be in black, to designate the front side of the receipt, and direct thermal printing on the reverse side of the receipt may be in red to designate the reverse side. The dual-sided, two-color direct thermal printing may also be used to call particular attention to the printing on one side of the media  20 , such as terms of sale or promotional material thermally printed in red on the reverse side of a receipt or other transaction document.  
      The description above presents a number of specific embodiments or examples of a broader invention. The invention is also carried out in a wide variety of other alternative ways which have not been described here. Many other embodiments or variations of the invention may also be carried out within the scope of the following claims.