A thermal printer using colorful rays and infrared rays for identifying colorant regions of an ink sheet is provided. The ink sheet includes a number of colorant region sets. Each colorant region set includes a yellow region, a magenta region, a cyan region and a black mark arranged at the beginning of the cyan region. The black mark is infrared ray non-transmittable. The thermal printer further includes an infrared ray source/an infrared ray sensor for sensing the black mark, and a blue ray source/a blue ray sensor (or an amber ray source/an amber ray sensor) for sensing the colorant regions.
A ribbon sensor includes a first and second emitter and a receiver. The first emitter is configured to transmit a yellow light signal and the second emitter is configured to transmit a blue light signal. The receiver is configured to produce an output signal in response to the transmission of the yellow and blue light signals through a panel of a print ribbon, wherein the output signal is indicative of a color of the panel. Additional aspects of the present invention are directed to a printer that includes the above-described sensor and a method of using the sensor to identify colored ribbon panels.
