DRIVE CONTROL DEVICE FOR HEATING ELEMENTS

摘要

PURPOSE: To provide the subject drive control device preventing the heat accumulation of heating elements, eliminating density irregularity and imparting excellent printing quality. CONSTITUTION: Printing data containing gradation data are outputted to the corresponding comparators 4a-4d through memories 3a-3d and the data of the number of gradations are outputted to the comparators 4a-4d from a gradation counter 5. Both data (number of gradations) are compared by the comparators 4a-4d and a drive signal (high signal) is outputted to shift resistors 2a-2d during a period when the gradation data of the printing data is larger than that of the data of the number of gradations outputted from the gradation counter 5 to drive heating elements. A frame counter 6 issues a command for stopping the output of the gradation counter 5 and the driving of a head control part 8 when the gradation counter 5 reaches a predetermined value to prevent the heat accumulation of the heating elements (thermal head).