The Mead Corporation

Robert A Wiley

James W Davis

Theodore F Williams

George W Denlinger

James H Yu

An ink jet printer includes a charge decoupling device which permits fluid flow of electrically conductive fluid between a high voltage electrode and a grounded fluid reservoir while presenting a high impedance electrical path therebetween. The charge decoupling arrangement includes a nonconductive casing defining an interior casing cavity which is separated into an upper and a lower portion by means of a perforated plate extending horizontally across the cavity. A plurality of drop stabilizers are mounted adjacent associated ones of the perforations to define downwardly extending capillary fluid paths from the perforations into the lower portion of the cavity to form fluid drops which drip off of the bottoms of the stabilizers. The break up of the fluid into drops provides the high impedance path through the charge decoupling device, thus ensuring that the deflection electrode arrangement and the catchers are substantially electrically isolated.

Ink jet printer and charge decoupling device therefor

A fluid supply system for an ink jet print head includes a recirculating path through a fluid pump, an inertial filter, and a variable restriction valve. Filtrate effluent from the inertial filter passes from the recirculating fluid path through a fixed restriction to the fluid supply line for the print head. The pressure drop across the fixed restriction is monitored and is utilized to control adjustment of the variable restriction valve in the recirculating fluid path such that the flow rate to the print head supply line is held constant. By this arrangement, the fluid within the print head may be maintained at a constant pressure level without the need for a pressure monitoring device directly associated with the print head.

Ink jet fluid supply system

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.

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Richardson, TX, United States of America

Robert A Wiley