PURPOSE: To make constant the print concentration and to avoid print error, in the print system printing desired character and graph, in which a plurality of print dot elements arranged on one line are sequentially scanned and the printed paper is continuously fed.

CONSTITUTION: The pulse motor 2 feeding heat sensing paper is driven with the four phase plses 1W4 from the pulse motor control section 3, and the line counter 41, latch time set circuit 43 and print time set circuit 44 are controlled with the synchronizing signal g in synchronizing with the control signal mc of the pulse motor control section in the control section 4 of the print drive unit. In parallel with 64 sets of bit clock BCL inputted, the data da is inputted to the driver section 6 by 64 bits and stored, and 64 bits of the block (a) are printed on heat sensing paper in parallel with the next 64-bit and simultaneously, the next 65W128-bit are inputted to the driver section to perform the print of blocks (b)W(d) sequentially.