Abstract
A high speed direct drive thermal print head, which prints across a 216 mm wide paper using 1728 heating resistor dots (8 dots/mm) has been developed.It can print 30 cm long paper in only a few seconds. The head consists of heating dots, over three hundred LSI chips, a couple of dozen capacitors and multilayer thin and thick film circuit substrate.The substrate is 240 × 70 mm by 1.0 mm thick conductor line width/space is 50 μ/50 μ. Hybridizing heating elements, drivers and shift registers on one substrate has made it possible to transmit signals serially into the head.Therefore, the I/O pin number has become far smaller than the number of dots, which has eliminated intermittent I/O pin disconnection.