Thermal printer, thermal printing system and printing method for thermal printer

The invention provides a thermal printer, a thermal printing system and a printing method for the thermal printer. The printing method comprises the steps of self-inspection, printing and fault processing. The self-inspection step comprises the steps that the state of the thermal printer is detected, and a state single is fed back; and if the state signal is a normal state signal, the printing step is performed. The printing step comprises the steps that printing data are received, and printing is performed according to the printing data; if the state signal is a fault state signal, the fault processing step is performed; the contact pin processing step comprises the steps of receiving the printing data and forwarding the printing data to a standby thermal printer; when the thermal printer fails, the complete or unprinted printing data are forwarded to the standby thermal printer through a communication unit, the standby printer continuously performs printing, and a user does not need to perform reconnection