Thermal printer and energizing control method therefor

A thermal printer having a thermal head with a heat element that heats a recording medium and forms a print dot by energizing the heat element generates a first energizing pulse that energizes continuously during a first period for forming a print dot when the recording medium conveyance speed is greater than a specific threshold value; and generates a second energizing pulse that alternates during a period that is longer than the first period when the recording medium conveyance speed is less than or equal to the threshold value, wherein the second energizing pulse alternates between energizing for a second period that is shorter than the first period and de-energizing for a third period.