Ink jet recording apparatus

Abstract

An ink jet recording apparatus which includes a recording head communicated via an ink supply needle with an ink tank and including electrodes for detecting a remaining amount of ink and being responsive to a print signal for spouting ink drops to recording paper, a capping unit abutting against the front of said recording head for holding the nozzle openings in an airtight state, a suction pump for supplying negative pressure to the capping unit, a resistance value detection circuit for detecting electric resistance across the electrodes for detecting a remaining amount of ink, a reference value storage unit for storing a resistance value across the electrodes relative to the remaining amount of ink in the ink tank, a resistance value comparison unit for comparing the resistance across the electrodes with the reference value, and a pump control unit responsive to the resistance value comparison result for controlling a pulse motor driving the suction pump. The resistance value detected by the resistance value detection circuit is compared with the reference value stored in the reference value storage unit to determine whether or not an ink tank is mounted, remounted, how much ink is in the ink tank, etc. Based on the determination result, the motor is controlled by the pump control unit for selecting the suction mode of ink from the recording head.