Thermal printers and methods for operating a thermal printer that applies donor material from donor patches on a donor ribbon to a received medium, the donor material being organized into sets, each set including at least one colored donor material patch and a protective material donor patch. Each ear lug has a pair of ears integrally formed therewith extending inwardly into the interior cavity of the box. The diagnostic statement creating modules have the functions of calculating a Z value for a diagnosed item and then generating a diagnostic statement in a natural language if there is a variation larger than usual with reference to a diagnostic parameter describing a model of a diagnostic statement corresponding to the range of the Z value. The result is less noise in the detection signals of the infrared sensor, and therefore a more sensitive and more reliable liquid detection method and liquid detection apparatus. It is particularly preferable that the drug capable of decreasing the post prandial blood glucose level close to the normal level is nateglinide.