DRIVING CIRCUIT FOR THERMAL HEAD

摘要

PURPOSE:To disperse low-density areas generated at boundary parts to the entire part of a recording image plane, by changing at random the dividing positions in driving M heat generating elements by dividing the elements into N blocks, on each recording for one line. CONSTITUTION:Recording data is written into a thermal head 1 through a D flip-flop 5, an exclusive OR gate 6 and an AND gate 7 according to setting of an integral number K into a decremental counter 4 by a controlling circuit 9, outputting of a block selection signal SEL and a clock signal CLK from a driving controlling circuit 3 and outputting of 512 bits of recording data D0 from a line buffer 2 synchronously with the signals SEL, CLK. The recording data D0 is written in the state of being divided into dk-dk+255, d0-dk-1 and dK+256-d511, the head 1 is driven in two divisions according to a latch signal L and a strobe signal ST, and the integral number K for the next operation is sequentially changed according to a a table of random numbers in the controlling circuit 9. Thus, apparently recording quality can be prevented from being deteriorated due to low-density areas generated at boundary parts.