Abstract: An ink jet fluid system includes a print head, defining a fluid reservoir, and further including at least one orifice communicating with the reservoir for generating a jet drop stream from the fluid flowing through the orifice. Inlet and outlet valves are connected to inlet and outlet openings of the print head, respectively, and a siphon line extending generally downward is connected to the outlet valve. A float valve, connected between the siphon line and the fluid supply system for the print head, vents the lower end of the siphon line to atmosphere to produce a sub-atmospheric fluid pressure within the print head after shutdown of the printer. The float valve includes a float which prevents air from entering the fluid supply through the valve. The float valve further is arranged so as to prevent ink within the valve from flowing out the vent opening.

Abstract: A method and apparatus for terminating the flow of liquid coating material from a jet drop recording device without splattering or seepage is provided. A supply of coating material under pressure is pumped through an inlet valve to a manifold in the printing head of the device. Shutdown is initiated by closing the inlet valve, terminating the supply of coating material. When the pressure in the manifold has dropped to the minimum required for normal operation of the recording device, an outlet valve connecting the manifold to a source of vacuum is opened, rapidly reducing the pressure in the manifold to atmospheric and terminating the flow of coating material from the printing head. A control unit is provided to open and close the valves and monitor the pressure inside the manifold to insure proper sequencing during the shutdown procedure.