Common causes leading to resistance burnout and protective layer breakdown in thermal printheads

Electrical aspects

• Abnormal power supply. Things like too high voltage or too large current, which go beyond the rated parameters of the printhead, can easily damage the resistor and the protective layer. Also, short - circuit in the circuit. If there is a short - circuit inside the printhead or in the external circuit, the sudden large current will impact and cause burning and breakdown.

Thermal management problems

• The printhead works frequently for a long time. The heat accumulates and can't be dissipated in time. Local overheating will make the resistor performance worse and the protective layer damaged by high temperature. If there is a failure in the heat dissipation system, like dust on the heat sink or the fan not working, the heat can't be dissipated, which will also make the heat damage worse.

Print media and operation

• Using thermal paper that doesn't meet the specifications. The characteristics of its coating may affect heat conduction and distribution, increasing the burden on components like the resistor. During printing, abnormal pressure, such as improper installation of the printhead or unsmooth paper feeding with extra frictional resistance, may make the printhead bear uneven force. Local stress concentration will damage the protective layer and the resistor.

Environmental factors

• The ambient temperature is too high, going beyond the working temperature range of the printhead. It's not good on its own, and with the heat from printing, problems are more likely to occur. Abnormal ambient humidity. Too high humidity may make the electronic components damp and affect electrical performance. Too low humidity is easy to generate static electricity, and electrostatic discharge may damage the printhead components.