Thermal printer

A thermal printer comprising:

• a main body that includes a sheet storage portion;
• an opening and closing lid that is pivotably provided on the main body and can open and close the sheet storage portion;
• a printing portion that includes a platen provided on one of the main body and the opening and closing lid, and a thermal head provided on an other and contacting or separating from the platen as the opening and closing lid is opened and closed;
• a locking portion that is provided on the main body and locks the opening and closing lid in a state where the opening and closing lid closes the sheet storage portion;
• a detection unit that detects a predetermined pressing state between the thermal head and the platen when a sensor provided in one of the main body and the opening and closing lid detects a detection target portion provided on an other;
• a controller that prohibits printing by the printing portion when the detection unit does not detect the predetermined pressing state;
• and
• a biasing member that biases the main body and the opening and closing lid in a direction in which the main body and the opening and closing lid are separated from each other so that the sensor does not detect the detection target portion in a state where the opening and closing lid is not locked to the locking portion.