Electro-mechanical apparatus

Claim 1

IN AN ON-THE-FLY PRINTER WHEREIN PRINT HAMMERS ALIGNED AT A PRINT STATION SELECTIVELY DRIVE A PAPER WEB AND A INKED RIBBON AGAINST A ROTATING PRINT ROLL TO EFFECT PRINTING ON SAID PAPER, A HOUSING PARTLH SURROUNDING SAID PRINT ROLL AND SUBSTANTIALLY CONCENTRIC THEREWITH, SAID HOUSING HAVING AN OPENING OPPOSITE SAID PRINT STATION TO ADMIT SAID HAMMERS, A RIBBON TRANSPORT ADAPTED TO MOVE SAID RIBBON UNDER PREDETERMINED TENSION IN MUTUALLY OPPOSITE DIRECTIONS PAST SAID OPENING IN A PATH A PORTION OF WHICH IS DETERMINED BY SAID HOUSING, TWO PAIRS OF SPACED CONTACT TERMINALS SUPPORTED ON OPPOSITE SIDES OF SAID OPENING AND ELECTRICALLY INSULATED FROM SAID HOUSING, EACH PAIR OF SAID SPACED CONTACT TERMINALS SUBSTANTIALLY SPANNING THE FULL WIDTH OF SAID RIBBON AND PROTRUDING INTO THE PREVAILING RIBBON PATHS, SAID RIBBON PATH BEING LOCALLY DISTORTED AROUND THE PERIPHERY OF SAID CONTACT TERMINALS ON A RADIUS WHICH IS SMALL RELATIVE TO THAT OF SAID HOUSING, SAID TENSIONED RIBBON, WHEN MOVING, PROVIDING A WIPING ACTION ON SAID CONTACT TERMINALS AT A PRESSURE SUBSTANTIALLY IN EXCESS OF THAT EXERTED ON SAID HOUSING BY SAID RIBBON AND SUFFICIENT TO MAINTAIN SELF-CLEANING CONDITIONS ON SAID CONTACT TERMINALS, SAID RIBBON HAVING A LEADER AT EACH END INCLUDING A PORTION OF CONDUCTIVE MATERIAL EX-