Patent ID: 7304658
Filing Date: 2007-12-04
Classification: B41J

Abstract:
1. A thermal printer including a line head that has heating elements arranged in a first direction and adapted to energize and heat said heating elements based on energizing time data related to printing data to thermally transfer ink of an ink film onto a sheet that is carried in a second direction perpendicular to said first direction, said thermal printer comprising: a first storage section for storing a heat history correction table that stores reference data related to first energizing time data and second energizing time data; a second storage section for storing at least the energizing time data for the current line to be printed, the energizing time data for the first preceding line printed immediately before the current line, and the energizing time data for the second preceding line printed immediately before the first preceding line; and a control section for obtaining energizing time data stored in said second storage section and for selecting reference data in said heat history correction table by assuming the energizing time data for a target dot in the current line as second energizing time data, while assuming the following energizing time data (1) to (3) as first energizing time data: (1) energizing time data for both adjacent dots positioned on either side of said target dot; (2) energizing time data for first-line adjacent dots constituting the first preceding line which are adapted to lie side-by-side, respectively, with said target dot and said both adjacent dots along said second direction; and (3) energizing time data for second-line adjacent dots constituting the second preceding line which are adapted to lie side-by-side, respectively, with said first-line adjacent dots along said second direction, and further for performing a corrective operation for the energizing time data for said target dot in such a manner as to change the start of energization in the energizing time data for said target dot using the following reference data (a) to (c): (a) reference data based on the energizing time data for said target dot and for said both adjacent dots; (b) reference data based on the energizing time data for said target dot and for said first-line adjacent dots; and (c) reference data based on the energizing time data for said target dot and for the dot lying side-by-side with said target dot along said second direction among said second-line adjacent dots, while in such a manner as to change the end of energization in the energizing time data for said target dot using the following reference data (d): (d) reference data based on the energizing time data for said target dot and for the dots lying side-by-side, respectively, with said both adjacent dots along said second direction among said second-line adjacent dots.