Browse Prior Art Database

Screen Copier for a Color Display

IP.com Disclosure Number: IPCOM000043308D
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Heybruck, WF: AUTHOR [+2]

Abstract

When using a thermal printer, the ability to copy a color display and retain the functions of distinguishing colors on paper is accomplished by printing dots of one color or a particular gray tone, depending on the type of paper used. With a special interface to the color display video signals, one can print the dots of each different color at a respectively different temperature, thereby creating gray tones or color depending on the type of thermal paper used. To vary the temperature of the dots affecting a color change on the paper, the time the dot is on or the voltage applied across the element may be changed. When time is used, the printing rate becomes color dependent, but by varying the voltage across the dot element, the printing rate can be held constant at its fastest possible rate.

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Screen Copier for a Color Display

When using a thermal printer, the ability to copy a color display and retain the functions of distinguishing colors on paper is accomplished by printing dots of one color or a particular gray tone, depending on the type of paper used. With a special interface to the color display video signals, one can print the dots of each different color at a respectively different temperature, thereby creating gray tones or color depending on the type of thermal paper used. To vary the temperature of the dots affecting a color change on the paper, the time the dot is on or the voltage applied across the element may be changed. When time is used, the printing rate becomes color dependent, but by varying the voltage across the dot element, the printing rate can be held constant at its fastest possible rate. The thermal printer screen copier accepts serial data and control signals from the interface to burn dots on the thermal paper. The data is shifted into a set of shift register drivers, where each bit corresponds to a printing element. By selectively sending the dots of a single color to the copier and selecting a corresponding voltage level from the power supply before printing, those dots can be printed on standard thermal paper with other dots printed at a different voltage level, thereby yielding some dots darker than others. This technique when used with multicolor paper will yield multicolor screen copying. A circuit to accomplish this is shown in Fig. 1. The technique of color printing does not increase the print time or printer cost in the magnitudes of existing color print methods, such as multihead ink jet or multipass ribbon. In fact, the process of copying a color display takes no more time than existing monochrome display copiers. Referring to Fig. 2, an adapter is shown which permits a color thermal printer scree...