Abstract: A digitally operated printer, particularly a laser printer, has a control system which controls supply of operational signals to the printer from a signal source. The control system incorporates a converter which converts groups of input signals into larger groups of operational signals. The operational signals are generated in correspondence with coded information carried by the input signals, e.g. by reference to a store of predetermined operational signals. The larger groups of signals are fed at a faster rate than the input signals, so that the effect is to enhance the grey tones produced by the printer.