Patent ID: 6618067
Filing Date: 2003-09-09
Classification: B41J,B41M

Abstract:
A thermal printer, comprising:an ink sheet, comprising a plurality of sets of colorant regions, each set of colorant regions comprising a first colorant region, a second colorant region, a third colorant region, a fourth colorant region, each colorant region having a front edge and a rear edge, a first mark formed within the third colorant region and adjacent to the second colorant region, and a second mark formed within the first colorant region and adjacent to the fourth colorant region; a first light source for emitting a first light toward the ink sheet, the first light being able to pass through the first colorant region and the fourth colorant region with a first level energy, and pass through the second and third colorant regions with a second level energy; a second light source for emitting a second light toward the ink sheet, the second light being able to pass through the first, second, third and fourth colorant regions with a third level energy, and pass through the first mark and the second mark with a fourth level energy; a first sensor generating a first signal when detecting the first level energy of the first light passing through the ink sheet; a second sensor generating a second signal when detecting the fourth level energy of the second light passing through the ink sheet; and a forwarding device, for forwarding the ink sheet to perform a movement relative to the first and second light sources; wherein which colorant region is positioned before the first and second light sources is determined by a combination of the first and second signals.