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Browse Prior Art Database

Enhanced Margin Cursor

IP.com Disclosure Number: IPCOM000048405D
Original Publication Date: 1982-Jan-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Cronch, DD: AUTHOR [+3]

Abstract

With the carrier of some single-element typewriters being provided with electrical connections for purposes of selection and print control, it is a simple matter to incorporate a print position indicator or margin cursor on the carrier of the typewriter.

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Enhanced Margin Cursor

With the carrier of some single-element typewriters being provided with electrical connections for purposes of selection and print control, it is a simple matter to incorporate a print position indicator or margin cursor on the carrier of the typewriter.

Fig. 1 illustrates an arrangement including a transparent margin scale 10 mounted across the front of a typewriter. Behind the margin scale 10 is a printed circuit board 16 attached to the carrier of the typewriter and carrying light-emitting diodes (LEDs) 14. The LEDs are switchable to illuminate one or the other to indicate not only the appropriate pitch selected by the operator but also the carrier position by providing light behind the margin scale 10. Power to the LEDs is provided via a cable 18 to the carrier of the typewriter.

Fig. 2 illustrates an implementing circuit arrangement for such an LED print position indicator. A +5 volts may be impressed upon the circuit across resistor 22, and in the event pitch switch 20 is open, the potential applied to the indicator driver 24 and inverter 26 is then +5 volts. Should pitch switch 20 be closed, the potential across resistor 22 is 5 volts and the potential applied to the indicator driver 24 and inverter 26 would then be ground potential. With the pitch switch 20 open, the input to indicator driver 24 would be 5 volts or high and the output of the indicator driver would then be low or substantially ground potential.

A secondary voltage so...