An ink jet recording apparatus wherein a sub-tank mounted on a carriage is replenished with ink from an ink cartridge as a main tank by the action of pressurized air from an air pressurizing pump. The torque of the input shaft is adjusted at the termination of the gear shifting on the basis of the lowered torque correction. An output driver is operative to receive the input signal and to adjust conditioning performed on the input signal to create an output signal for transmission over a communication channel, where the adjustment is based on the detection by the signal detector.