To highly accurately control a pulse width in a printing controller.

There are provided accumulators 14, 24 and 54 whose outputs change by every constant value with reference to clocks from an oscillator 5, memories 15, 25 and 55 for storing amplitude values as a reference table, D/A converters 16, 26 and 56 for converting digital values read out from the memories to analog values with using outputs of the accumulators as addresses, low pass filters 17, 27 and 57 for cutting high frequency components of outputs of the D/A converters, comparators 18, 28 and 58 for comparing output analog values of the low pass filters, and a selector 9 for generating a plurality of delayed clocks of different phases by shifting read start addresses of the memories by a predetermined value, and generating pulses of a width conforming to image data from a phase difference of the clocks.