To make it possible to easily change printing characters without adding a treatment to data.

The ink-jet printer using a cartridge 20 provided with two or more nozzles n in parallel with two trains is equipped with a memory section 14 for storing the data for one train of two or more nozzles, a one-train data storage section 13 for storing the data for one train ahead the data for the one train stored in the memory section, and a control section 11 for printing also the dot on the right-hand of a printing dot and realizing a thick-character printing by taking the logical sum of the data for one train in the memory section 14 and the data for one train in the one-train storage section 13 and by controlling an ink jetting from nozzles based on the result of the logical sum. Or, the printer is equipped with the control section 11 for printing also the dot under the right-hand of the printing data and realizing a character printing with shadow based on the result of the logical sum.