Ink jet recording apparatus of the continuous jet type and automatic ink jet jetting axis adjusting method of the same

Claim 1

An ink jet recording apparatus of the continuous jet type, comprising: disintegrating means for jetting pressurized ink from a nozzle along an ink jet jetting axis to disintegrate the ink into a uniform train of ink drops; charging means for selectively charging the ink drops in accordance with a controlling signal; deflecting means for deflecting charged ones of the ink drops perpendicularly to the ink jet jetting axis; separating means for selectively intercepting the ink drops in accordance with the amount of deflection by said deflecting means; a bias power source for generating a bias potential; a high voltage switch for receiving and voltage amplifying a recording signal and adding the bias potential outputted from said bias power source to the amplified recording signal to produce a controlling signal; a test signal generator for adding the bias potential outputted from said bias power source to a first test signal having a level higher than 0 but lower than a voltage amplitude of the recording signal amplified by said high voltage switch to generate a second test signal; a change-over switch for selectively applying one of the controlling signal outputted from said high voltage switch and the second test signal outputted from said test signal generator as a controlling signal to said charging means; a conductive drop catcher disposed behind said separating means for catching those ink drops which have passed by said separating means; current detecting means connected to said conductive drop catcher for detecting the charge carried to said conductive drop catcher by the ink drops; and controlling means for controlling the bias potential to be outputted from said bias power source in accordance with an output of said current detecting means.