Patent ID: 6504561
Filing Date: 2003-01-07
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 at the front edge of the third colorant region, and a second mark formed at the front edge of the first 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 adjacent to the first and second light sources is determined by a combination of the first and second signals; wherein the first, second, third and fourth colorant regions are substantially as wide as the ink sheet, and the front edge of the first colorant region is completely adjacent to the rear edge of the fourth colorant region, and the rear edge of the first colorant region is completely adjacent to the front edge of the second colorant region, wherein the second light source is an infrared red light source and the second sensor is an infrared light sensor, wherein the first and second marks are substantially infrared light non-transmissable, wherein the first light source is an amber light source and the first sensor is an amber light sensor, and wherein the second and third colorant regions of each set of colorant regions are substantially amber light non-transmissable.