To provide a portable printer which can meet various kinds of paper and can prevent discontinuance of printing due to shortage of power of a battery.
A paper cartridge 4 equipped with a second paper passing route 30 communicating with a first paper passing route, and with a battery 21, is so designed that it can be fitted to and removed from a portable type printer base part 3 equipped with a printing part in the first paper passing route, and an exterior case 2 is formed of the printer base part 3 and the paper cartridge 4. By preparing a plurality of kinds of paper cartridges 4 for different kinds of paper 28, the kind of the paper 28 for printing can be selected only by replacement of the paper cartridge 4. Since the paper cartridge 4 can be formed in a minimum size corresponding to the paper 28 to be used, in this case, a useless increase in dimensions of an external shape can be prevented. By setting the capacity of the battery beforehand in conformity with the amount of consumption of the paper 28 to be used, discontinuance of printing due to shortage of power of the battery in the course of printing is eliminated.
NAKAEDA MASAYUKI
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