Abstract: An improved thermal printer has circuits that are responsive to selected parameters of the printer and to the contents of a document to be printed to selectively enable the individual printing electrodes with printing impulses of varying energy depending upon when the electrode had printed. Other circuits cause the selective process to be responsive to whether electrodes adjacent a selected electrode had printed and how recently such printing took place. In different embodiments, circuits utilize not only the history of a selected electrode and its neighbors, the as yet unprinted portion of the document to be printed is utilized to aid in the selection of an appropriate printing impulse.