Patent ID: 7014290

Claim:
A method for detecting a short-circuit problem in an ink jet printer, the ink jet printer comprising: at least an ink jet unit comprising an input end, a corresponding nozzle, and a control end; a driving circuit for providing energy to the ink jet unit via the input end; and a switch connected to the input end of the ink jet unit, wherein when the ink jet unit is receiving energy provided by the driving circuit, the switch is opened; wherein when the ink jet unit receives an ink jet signal via the control end, the ink jet unit is capable of spitting ink via the corresponding nozzle according to the energy received via the input end; the method comprising: stopping transmitting the ink jet signal to the control end of the ink jet unit; stopping providing energy to the input end of the ink jet unit; and measuring currents flowing through the input end of the ink jet unit and the switch when the switch is closed.