GB1478325A - Strike-correcting arrangement for print hammers - Google Patents

Abstract

1478325 Control of printers COMPAGNIE INTERNATIONALE POUR L'lNFOBMATIQUE CII-HONEYWELL BULL 4 Sept 1974 [5 Sept 1973] 38660/74 Heading G4H A control circuit for a belt printer comprises means for adjustably delaying hammer actuation to compensate for variations in the speed of the character support. The belt 101, Fig. 1 (not shown) contains holes, corresponding with characters thereon, which are sensed to provide signals indicating which character will next be in alignment with a hammer. At time t 0 , Fig. 3 a monostable provides a delay pulse of length td, after which the hammer strike amplifier is actuated. The hammer and belt trajectories M 1 , D coincide at time t 2 if the belt is moving with speed V; if the speed has altered to (V-#V) then coincidence takes place at time t 2 , but there is a degree of misalignment F 1 , F 1 <SP>1</SP>. The control circuit of the present invention delays actuation of the monostable by a time tr so that the hammer trajectory becomes M 2 , and the hammer strikes the character at time t 3 in alignment therewith. The delay time tr = t 3 - t 2 . The control circuit comprises means 2, Fig. 2 (not shown) for counting N pulses (Nα actual strike time as dictated by the actual speed of the support); the count N is fed, to a subtractor together with a number N<SP>1</SP>α strike time relative to the nominal speed of the support. The difference #N=N-N<SP>1</SP> is fed to a counter (5) which counts down in a time equal to the required delay tr, after which a signal is passed to the monostable (7).