Patent ID: 6283648
Filing Date: 2001-09-04
Classification: B41J

Abstract:
A thermal head control circuit for developing at least two colors on a thermosensitive paper by providing heat on said thermosensitive paper on a dot-by-dot basis, comprising:a thermal head having a plurality of heating resistor elements, for providing heat on said thermosensitive paper on the dot-by-dot basis;a print data circuit for generating print data indicating whether or not each of the individual heating resistor element in said thermal head is to be electrified irrespective of the color to be developed,a color development data circuit for generating color development data indicating which color should be developed on the dot-by-dot basis;an electrifying circuit for electrifying each of the individual heating resistor element according tc said print data; anda current switching circuit for switching a magnitude of current flowing to said electrifying circuit according to said color development data to develop the colors on said thermosensitive paper, said current switching circuit comprising:a current limiting element for limiting the current flowing through the respective heatingresistor elements in the thermal head, anda control circuit responsive to said color development data for controlling whether or not each current limiting element should be electrically connected to the corresponding heating resistor element.