| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inspection to determine a defective driver IC among a plurality of driver ICs provided on a thermal head whereby the inspection can be surely and simply executed in a short time at a low cost. SOLUTION: A constant current I is inputted from a COM terminal of a thermal head H and only one switching transistor device in driver ICs d1-d3 on the thermal head H is turned on and other switching transistor devices are turned off and then a voltage across the COM terminal and a GND terminal is measured. By sequentially changing the switching transistor devices to be turned on, the voltages between the COM terminal and GND terminal of all of the switching transistor devices s1-s9 are measured and the average of the measured voltages is obtained. It is judged that a driver IC including a switching transistor device having the detected voltage which is greater than the 1.1 times of the average is to be a defective one.
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