PURPOSE: To enable to arbitrarily select printing speed and printed quality in accordance with use, by providing an operation-setting part for arbitrarily setting a signal-generating period of a printing timing generator and a selecting part for changing a printing parameter in accordance with a value set by the setting part.

CONSTITUTION: Periods of a CRMP signal 102 and a DPR signal 103 outputted from the timing signal generator 10 are changed by a TC signal 101 outputted from a timing adjustor 11, whereby printing speed is changed. Further, by the TC signal 101 outputted from the timing adjustor 11, a printing parameter suitable for the printing speed is supplied from a printing parameter selector 40 to a head-driving circuit 31. By operating a switch on the timing adjustor 11, it is possible to select between high-speed printing and low-speed printing. For example, high-speed printing is adopted in the case of a rough copy, and low-speed printing (high-quality printing) is adopted in the case of a fair copy.