Print head pulsing techniques for multicolour thermal direct colour printers

摘要

A direct thermal printer comprises a thermal print head having a plurality of heating elements, and a controller connected to the thermal print head that applies, during a first portion of a printing time, a first pulse pattern to the heating elements, and that applies, during a second portion of the printing time, a second pulse pattern to the heating elements. The first pulse pattern comprises a first plurality of pulses having a first average power, each of the first plurality of pulses having a common energy, wherein the first portion of the printing time comprises a first plurality of subintervals, and wherein the first plurality of pulses is provided in a plurality of consecutive subintervals. The second pulse pattern comprises a second plurality of pulses having a second average power that differs from the first average power, wherein each of the second plurality of pulses has the common energy, wherein the second portion of the printing time comprises a second plurality of subintervals, and wherein the second plurality of pulses is provided in a plurality of nonconsecutive subintervals.