A THERMAL PRINTHEAD DETECTING DEVICE AND METHOD AND A THERMAL PRINTER USING THE SAME

摘要

A thermal printhead detecting device comprises: a power supply (1), a power supply switch (4), a power supply switch controlling circuit (5), a first detecting resistance (Ra), a second detecting resistance (Rb), a printhead (2) to be detected, and a printhead controlling circuit (3). An output end of the power supply (1) is connected to a common joint (N) of heating elements of printhead through the power supply switch (4). The first detecting resistance (Ra) is connected in parallel with the power supply switch (4). An output end of the power supply switch controlling circuit (5) is connected to a controlling end of the power supply switch (4). One end of the second detecting resistance (Rb) is connected to the common joint (N) of the heating elements, and the other end of it is grounded. Gating for every heating element is controlled by the printhead controlling circuit (3). The thermal printhead detecting device doesn't need an exclusive power supply so that the circuit of the device can be simplified, and the cost of it is decreased.