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Contrast Control for a Resistive Ribbon Printer From a Personal Computer Keyboard

IP.com Disclosure Number: IPCOM000039739D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Higdon, JM: AUTHOR [+4]

Abstract

A personal computer (PC) may function as a typewriter by having a resistive ribbon printer, which is connected thereto, print on a sheet of paper in the printer as soon as each key of the PC keyboard is depressed. In such a system, it is necessary to have fine control over the print and erase currents for the electrodes of the printer. This is obtained with a five-way switch implemented in the PC software and activated from the PC keyboard. In a PC having a resistive ribbon printer connected thereto and used to print characters on a sheet of paper in the printer as soon as each key of the keyboard is depressed so that the apparatus functions as a typewriter, it is necessary to have an erase function in addition to a print function.

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Contrast Control for a Resistive Ribbon Printer From a Personal Computer Keyboard

A personal computer (PC) may function as a typewriter by having a resistive ribbon printer, which is connected thereto, print on a sheet of paper in the printer as soon as each key of the PC keyboard is depressed. In such a system, it is necessary to have fine control over the print and erase currents for the electrodes of the printer. This is obtained with a five-way switch implemented in the PC software and activated from the PC keyboard. In a PC having a resistive ribbon printer connected thereto and used to print characters on a sheet of paper in the printer as soon as each key of the keyboard is depressed so that the apparatus functions as a typewriter, it is necessary to have an erase function in addition to a print function. This is not required when the printer is used solely as a printer for a PC since printing would occur only after storage within the memory of the PC so that corrections would be made on the stored material before print out. A resistive ribbon printer requires only a three-way switch for contrast control during printing to control the print current to its electrodes. However, good erasure requires five different currents to the electrodes of the printer since double erase must be performed for acceptable erasures of underscored and expanded characters, for example. Accordingly, the software in the PC implements a five-way switch, when using a printer comma...