Print head pulsing techniques for multicolor printers

Abstract

In one aspect of the invention there is disclosed a multicolor thermal imaging system wherein different heating elements on a thermal print head can print on different color-forming layers of a multicolor thermal imaging member in a single pass. The line-printing time is divided into segments, each of which is divided into a plurality of subintervals. All of the pulses within the segments have the same energy. In one embodiment, every pulse has the same amplitude and duration. Different colors are selected for printing during the different segments by varying the fraction of subintervals that contain pulses. This technique allows multiple colors to be printed using a thermal print head with a single strobe signal line. Pulsing patterns may be chosen to reduce the coincidence of pulses provided to multiple print head elements, thereby reducing the peak power requirements of the print head.

1 . A method comprising steps of:
 (A) identifying a first plurality of pulses to be provided to a thermal print head element in a first segment of a first line time, the first plurality of pulses having a first average power, wherein each of the first plurality of pulses has a common predetermined energy; and   (B) identifying a second plurality of pulses to be provided to the thermal print head element in a second segment of the first line time, the second plurality of pulses having a second average power that is less than the first average power, wherein each of the second plurality of pulses has the common predetermined energy; and   (C) identifying a third plurality of pulses to be provided to the thermal print head element in a third segment of the first line time, the third plurality of pulses having a third average power that is less than the second average power, wherein each of the third plurality of pulses has the common predetermined energy.   
     
     
         2 - 24 . (canceled)