Abstract: Disclosed is improved apparatus for inhibiting the emission of a stream of ink drops from the nozzle orifice of an ink jet printer. The apparatus comprises a valve which is located externally of the head associated with the nozzle, and adjacent the outlet orifice of the nozzle. The valve includes a resilient gate member which is mounted for movement with respect to the outlet orifice but adjacent thereto, the gate member being movable between a first position allowing an uninhibited emission of a stream of ink drops from the outlet orifice of the nozzle and a sealing position of the outlet orifice when the gate member is in a second position. In this connection, the outlet orifice serves as a seat for the gate member when the member is in the second position. Moreover, the gate member is preferably composed of a thin but resilient material which is biased into a sealing engagement with the seat at least when the gate member is in the second position.