Apparatus and method for printing two colors in a single pass using thermally sensitive direct and transfer media
AssigneeInternational Business Machines Corporation
InventorRichard Hunter Harris
Life of this patent
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Abstract
A thermal printing mechanism prints a black pattern on a paper web with a direct printing process and additionally prints a color pattern on the paper web with a transfer printing process. The paper web and a transfer film web are moved between a platen and a thermal printhead, with the transfer film web between the paper web and the printhead, with heating elements within the printhead being operated at one temperature to produce the color pattern and at another, higher temperature to produce the black pattern. Preferably, the transfer film web is moved only when the color pattern is being printed and when it is otherwise necessary to prevent the film web from being worn through as the black pattern is printed.
Claims17
Apparatus providing for direct thermal printing on a paper web having a first thermally sensitive coating turning from a light condition to a darkened condition at temperatures above a first temperature, wherein said apparatus additionally provides for transfer thermal printing on said paper web, and wherein said apparatus comprises:
- a thermal printhead;
- a paper drive motor moving said paper web in a first direction past said thermal printhead and in proximity with said printhead, with said first thermally sensitive coating facing said thermal printhead;
- a transfer film web extending between said thermal printhead and said paper web including a second thermally sensitive coating facing said paper web;
- a film drive motor moving said transfer film web in a second direction between said thermal printhead and said paper web;
- and
- a plurality of heating elements extending within said thermal printhead adjacent said transfer film web, individually operable to produce a pattern of heated and darkened areas on said first thermally sensitive coating of said paper web and to transfer a pattern of material from said second thermally sensitive coating to said paper web from said transfer film web as said paper web is moved in proximity to said thermal printhead.
A method for printing black and color patterns on a paper web having a thermally sensitive direct printing layer darkening when exposed to a first temperature, wherein said method comprises:
- holding said paper web against a transfer film web having a thermally sensitive transfer layer, wherein said thermally sensitive direct printing and transfer layers are disposed adjacent one another;
- applying heat in a first pattern to a side of said transfer film web opposite said paper web to produce a black pattern of darkened material within said thermally sensitive direct printing layer;
- and
- applying heat in a second pattern to said side of said transfer film web opposite said paper web to cause portions of said thermally sensitive transfer layer to transfer from said transfer film web to said paper web, wherein said heat applied in said second pattern is insufficient to produce a black pattern of darken material within said thermally sensitive direct printing layer.
Dependencies are inferred from the claim text.