Apparatus for correcting the way in which print hammers strike

In a strike connection circuit arrangement for an impact printer comprising a carrier for moving a character past a sheet support at a nominal speed, reference indicator means for identifying the location of the character on the carrier, first sensor means associated with said carrier for generating a synchronizing pulse in response to the movement of the reference indicator means past a first predetermined location, at least one strike hammer adapted to be energized from a rest position to a strike position in contact with the character to effect a print out of the character on the sheet while the carrier is moving, control circuit means operably connected to said strike hammer for controlling the energization thereof including a logic unit responsive to said synchronizing pulse, a delay generator connected to said logic unit for generating a delay pulse in response to said synchronizing pulse and a strike amplifier responsive to said delay pulse for controlling the energization of said strike hammer, the improvement comprising:

• second sensor means associated with said carrier for generating a check pulse in response to movement of said indicator past a second predetermined location, circuit means for generating a deviation signal representing the deviation of the actual carrier speed from the nominal carrier speed in response to the time interval separating said synchronizing pulse and said check pulse, and said delay generator being responsive to said deviation signal to thereby control the time in which the delay generator generates said delay pulse, said time being proportional to the value of the deviation signal, and said time of generation commencing with the receipt of the synchronizing pulse by the delay means.