Thermal printers

Claim 1

A THERMAL PRINTER COMPRISING A PRINT HEAD CAPABLE OF MARKING A THERMALLY-SENSITIVE RECORD MATERIAL HAVING A PLURALITY OF RESISTIVE ELEMENTS ARRANGED IN THE FORM OF A MATRIX AND A RESPECTIVE ELECTRICAL CIRCUIT MEANS FOR EACH OF SAID RESISTIVE ELEMENTS WHEREBY THE CHARACTER TO BE PRINTED MAY BE OUTLINED AS A SERIES OF DOTS BY ENERGIZING SELECTED ONES OF SAID ELECTRICAL CIRCUIT MEANS WITH A SHORT DURATION ELECTRICAL PULSE WHICH PRODUCES IN THE CORRESSPONDING RESISTIVE ELEMENTS A TEMPERATURE RISE OF SUFFICIENT MAGNITUDE TO PRODUCE MARKS IN THE FORM OF DOTS ON THERMALLY SENSITIVE RECORD MATERIAL IN COOPERATIVE RELATIONSHIP THEREWITH, A SOURCE OF DIRECT CURRENT POTENTIAL, A TRANSPORT MECHANISM FOR ADVANCING SAID RECORD MATERIAL BY AND IN COOPERATIVE RELATIONSHIP WITH SAID PRINT HEAD, A PLURALITY OF KEYS EACH CORRESPONDING TO A CHARACTER TO BE PRINTED, A MAGNETIC CORE OF THE TYPE HAVING SUBSTANTIALLY SQUARE HYSTERESIS LOOP CHARACTERISTICS CORRESPONDING TO EACH OF SAID PLURALITY OF RESISTIVE ELEMENTS ON SAID PRINT HEAD, A SET WINDING FOR EACH CHARACTER TO BE PRINTED AND EACH THREADING ALL OF SAID CORES WHICH CORRESPOND TO THE SAID RESISTIVE ELEMENTS WHICH MUST BE ENERGIZED TO FORM THAT CHARACTER, A SENSE WINDING THREADING EACH OF SAID CORES, A READ-OUT WINDING THREADING ALL OF SAID CORES IN A SENSE OPPOSITE THAT OF SAID SET WINDINGS, AN ELECTRICAL SWITCH MEANS ASSOCIATED WITH AND OPERATED BY EACH OF SAID KEYS FOR ESTABLISHING A FIRST ELECTRICAL CIRCUIT FROM SAID SOURCE OF DIRECT CURRENT POTENTIAL THROUGH THE SAID SET WINDING FOR THE CHARACTER TO WHICH THE ASSOCIATED KEY CORRESPONDS FOR SETTING THE THREADED CORES IN A SELECTED STATE OF MAGNETIC REMANENCE, A READOUT SWITCHING CIRCUIT MEANS FOR COMPLETING A SECOND ELECTRICAL CIRCUIT THROUGH SAID READ-OUT WINDING FOR REVERSING THE STATE OF MAGNETIC REMANENCE OF THOSE CORES WHICH HAVE BEEN SET THEREBY PRODUCING A PULSE IN THE SENSE WINDINGS OF SAID REVERSED CORES, A RESISTIVE ELEMENT SWITCHING CIRCUIT MEANS CORRESPONDING TO EACH OF SAID RESISTIVE ELEMENTS OF SAID PRINT HEAD EACH OF WHICH IS RESPONSIVE TO THE SAID PULSE APPEARING IN THE SAID SENSE WINDING OF SAID CORRESPONDING CORE UPON THE REVERSAL OF THE STATE OF MAGNETIC REMANENCE OF THAT CORE FOR SELECTING THE RESPECTIVE RESISTIVE ELEMENTS TO BE ENERGIZED, MEANS FOR ENERGIZING SAID SELECTED RESISTIVE ELEMENTS WITH A SHORT DURATION ELECTRICAL PULSE, AND A TRANSPORT SWITCHING CIRCUIT MEANS RESPONSIVE TO SAID READ-OUT SWITCHING CIRCUIT MEANS FOR ENERGIZING SAID TRANSPORT MECHANISM FOR ADVANCING SAID RECORD MATERIAL.