Thermal head printer

Abstract

A thermal print head includes a plurality, e.g., three of delay shift registers operating by a clock-controlled shift scan to receive dot print signals from a dot print signal generating circuit. The delay registers have a number of addresses corresponding to the number of dot print elements in the printer head. The dot print signals from the delay shift registers are applied to an OR gate connected to the print registers for the dot print elements. With this construction, the shift scan cycle t is set so that t=T (n+1), where T is the least print cycle under normal printing conditions and n is the number of delay shift registers. Printing is effected with a high resolving power to restrain any decline in coloring properties using interpolation dot print signals derived from real time print signals by the delay shift registers. The real time signals ae obtained by sampling an analogue wave as a digitized value and counting the number of clock pulse needed to equal this digitized value, at which time a signal is given.