Ink jet recording apparatus of the continuous jet type

Claim 1

An ink jet recording apparatus of the continuous jet type, comprising: nozzle means for receiving pressurized ink and forming the received pressurized ink into a uniform ink jet which disintegrates into a train of ink drops; recording signal generating means for generating a controlling voltage in response to s recording signal; charging means including a controlling electrode at which a recording signal from said recording signal generating means is received for selectively charging an ink drop; deflecting means for forming a deflecting electric field perpendicular to an ink jet flying axis to deflect a charged ink drop in a direction perpendicular to the ink jet flying axis; separating means for cutting a deflected ink drop but allowing s non-deflected ink drop to pass thereby; test signal generating means for generating a controlling signal which varies continuously; switch means for selectively coupling one of said recording signal generating means and said test signal generating means to said controlling electrode of said charging means; an electrically isolated conductive drop catcher for catching an ink drop which has passed by said separating means; current detecting means connected to said conductive drop catcher for detecting electric charge carried to said conductive drop catcher by charged ink drops as an electric current; and relative position detecting means for measuring a relative positional relationship between the ink jet flying axis and said separating means from a controlling voltage outputted from said test signal generating means and an output of said current detecting means.