Abstract: A driver circuit for driving an array of inkjet printer actuators, comprising a serial input (15, 20) for receiving serial print data, a register (25, 26) for storing the print data in the form of event and event timing data pairs, a parallel output (30, 32) for outputting event data and control circuitry (42, 48) for controlling the timing of output of event data according to corresponding event timing data. The driver circuit preferably comprises a programmable part (10) and a fixed part (11, 12, 13, 14), in which the programmable part stores selectable pre-programmed waveforms and outputs event and time data pairs to the fixed circuit part, which controls the timing of output of the event data.