| 摘要 |
PROBLEM TO BE SOLVED: To provide a failure detection apparatus and a method for quickly finding out a failure of a head driver IC temperature detection circuit in an ink jet printer. SOLUTION: In the ink jet printer for comparing a forward voltage of a diode in the head driver IC with an output voltage from a D/A converter by using a comparator and detecting a temperature, preset values of the D/A converters of a plurality of the head driver ICs are periodically and sequentially switched to the maximum value when power is turned on, printing is idle, a new page is processed during printing, etc. If a temperature detection signal switches to an L level, normal operation of the corresponding temperature detection circuit can be confirmed. If all signals do not switch, the failure in the temperature detection circuit such as breaking of wire in an FFC is suspected. COPYRIGHT: (C)2004,JPO |
