High resolution thermal printers including a print head with heat producing elements disposed at an acute angle

摘要

The present invention relates to thermal printers including a thermal print head mounting a plurality of N thermal heating devices such as lasers or resistive heating elements. In the thermal printer, a receiver member is mounted on a rotating drum with a dye carrier member engaging the outer surface of the receiver member in a dye frame image printing area. The thermal heating devices are aligned at a predetermined acute angle &THgr; to a line normal to the rotation of the drum. During the high speed rotation of the drum, the thermal heating devices are selectively energized by micropixel clock pulses which are synchronized to the rotational speed of the drum. During each rotation of the drum, N columns of micropixels are printed on the receiver member. Additionally, the energizing of each of the thermal heating elements is timed using the micropixel clock pulses so as to print corresponding micropixels of the N columns of micropixels in a line normal to the rotation of the drum. As the drum is rotating at a high speed, the print head is translated normal to the direction of rotation of the drum to print all of the (N×M) columns of the dye frame image next to each other with a 1/8 micropixel resolution.