Line-at-a-time printer

Claim 1

A PRINTING APPARATUS COMPRISING: A ROW OF ELECTRICALLY CONDUCTIVE PRINTING ELEMENTS MOUNTED SIDE-BY-SIDE FOR MOVEMENT TRANSVERSELY TO SAID ROW FROM A GIVEN REST POSITION TO A GIVEN ACTIVE PRINTING POSITION, EACH SAID ELEMENT COMPRISING A PRINTING POINT PROJECTION, A FIRST CONTROL PORTION, AND A SECOND CONTROL PORTION, EACH OF SAID SECOND CONTROL PORTIONS HAVING A FLAT SURFACE PARALLEL TO THE PLANE IN WHICH THE PRINTING ELEMENT MOVES; FIRST MEANS EXTENDING PARALLEL TO SAID ROW ADJACENT SAID FIRST CONTROL PORTIONS AND OPERATIVELY COUPLED THERETO FOR APPLYING FORCES, WHEN ENERGIZED, TO SAID ELEMENTS TENDING TO MOVE SAID ELEMENTS FROM THE SAID REST POSITIONS TO THE SAID ACTIVE PRINTING POSITIONS THEREOF; SECOND MEANS EXTENDING PARALLEL TO SAID ROW ADJACENT SAID FIRST CONTROL PORTIONS AND OPERATIVELY COUPLED THERETO FOR APPLYING FORCES, WHEN ENERGIZED, TO SAID ELEMENTS TENDING TO RESTORE SAID ELEMENTS TO THE SAID REST POSITIONS; A SERIES OF CONTROL MEMBERS ARRANGED IN A ROW PARALLEL TO SAID ROW OF ELEMENTS AND OPERATIVELY COUPLED RESPECTIVELY THERETO FOR APPLYING FRICTIONAL RESTRAINING FORCES, WHEN ENERGIZED, TO THE SECOND PORTIONS OF RESPECTIVE ONES OF SAID PRINTING ELEMENTS IN THE REST POSITIONS THEREOF, EACH OF SAID SERIES OF CONTROL MEMBERS COMPRISING A FOIL CONSTRUCTION CONTAINING A LAYER OF ELECTRICALLY CONDUCTING MATERIAL POSITIONED CLOSELY PARALLEL TO THE FLAT SURFACE OF SAID ELEMENT AND SEPARATED THEREFROM BY A LAYER OF INSULATING MATEIAL; MEANS FOR ALTENATELY ENERGIZING SAID FIRST AND SECOND MEANS; AND MEANS OPERATIVELY CONNECTED TO SAID ENERGIZING MEANS AND OPERATIVE ONLY WHEN SAID SECOND FORCE-APPLYING MEANS IS ENERGIZED FOR SELECTIVELY ENERGIZING SAID CONTROL MEMBERS TO APPLY FRICTIONAL FORCES TO SELECTED ONES OF SAID SECOND PORTIONS, THEREBY PREVENTING THE CORRESPONDING PRINTING ELEMENTS FROM MOVING TO THE ACTIVE PRINTING POSITION.