Ronald F Swaim

US Patent:

42181500, Aug 19, 1980

Filed:

Nov 20, 1978

Appl. No.:

5/962095

Inventors:

Ronald L. Swaim - Sunnyvale CA

Assignee:

Vydec, Inc. - Florham Park NJ

International Classification:

B41J 312

US Classification:

400124

Abstract:

A moving coil mechanism is utilized to operate each individual print wire of a matrix printing head. Static magnetic fields for the moving coil mechanism may be provided by permanent magnets. Also disclosed is a method for compensating varying frictional forces by sensing the voltage induced in the moving coil and utilizing the information so obtained as an indication of print wire velocity. Current drive to the moving coil can then be modified to maintain print wire velocity substantially independent of varying frictional forces. Also disclosed is an interspersed, or "nested," arrangement of moving coil mechanisms which contributes to the compactness of the improved matrix printer.