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.
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.
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.
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.
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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.
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.