The wide-format dual-line 1200 dpi thick film thermal head was developed utilizing the following technologies: (a) an alternated conductive lead circuitry inside the thermal head is devised in that it does not use diodes for the prevention of reverse current; instead, it adds a secondary power supply to redirect the reverse current. (b) The heater nib line of the printhead is produced stably and accurately using the direct dispensing system which, based on the air microtechnology, feeds back the air pressure and controls the linear actuator to follow the surface of a substrate. (c) The 1200 dpi printhead is combined of two identical 600 dpi nib lines with half-pitch offset in the nib line direction and separated by a distance of 32 nib lines in the printing direction. Although the printhead is not made of a 1200 dpi single nib line and may be classified as a quasi-1200 dpi printhead in a more strict sense; however, it does exhibit a 1200 dpi-like performance and, for the convenience of presentation, it is still called a 1200 dpi printhead in this article. Several wide-format (up to 54 in. width) products based on the 1200 dpi thermal printhead have been designed and are capable of printing half-tone images of up to 133 lines per inch.