Abstract: An improved damping system for continuous ink jet printers of the kind having: (i) a print head, including an ink cavity and an orifice plate coupled to the cavity, and (ii) an ink circulation system having an ink supply conduit to the print head cavity inlet and an ink return conduit coupled to the cavity outlet. The damping system reduces ink pressure transients within said print head means and includes: (i) a damping chamber for enclosing a gas-over-ink region that is coupled to the ink return conduit at a location proximate the print head and (ii) a printer subsystem for periodically introducing gas into said ink return conduit upstream of the damper chamber.

Abstract: An ink cartridge constructed for insertion into a continuous ink jet printer, includes a reservoir for containing an ink supply, an outlet for coupling the ink reservoir to a printer supply line, cartridge venturi elements having (i) a restriction region, (ii) an expansion region and (iii) an inlet for detachable coupling to an ink bypass line of such printer. The cartridge also includes an ink return inlet couplable to an ink return line(s) of the printer and a path defining an ink induction passage that extends from the venturi restriction region to the ink return inlet. Structural features of printer apparatus, adapted to cooperate with such a cartridge, are also disclosed.

Abstract: A cleaning system for ink jet printing orifices includes cooperative elements which provide varying pressure differentials across the orifice plate that oscillate ink into and out of the orifices. In one embodiment the pressure differentials are implemented by varying the impedance to ink cross-flow through a print head cavity while pressurizing a region around the exterior of the orifices.

Abstract: An ink jet printer having an ink supply tank and a constant volume fluid pump which pumps ink through a supply line to a print head and, during a start up sequence, to a pressurizing line having a fluid accumulator which rapidly increases the line pressure of the system until a predetermined ink pressure within the print head is reached. The pressure is sensed by a transducer adjacent the print head, and an outlet valve is actuated to close the flow of ink through the head abruptly, thereby creating a pressure wave which initiates ink flow through the orifices of the print head. In order to minimize contamination of ink in the supply line, the pressurizing line conveys ink back to the supply tank.

Abstract: An ink supply system for supplying ink to the print head of an ink jet printer includes a pump arrangement having a pump outlet for supplying ink to the print head from a supply tank through a print head supply line. A closed container communicates with the pump outlet and the print head for holding a quantity of ink therein for providing a second flow of ink to the print head at a static pressure that increases linearly with time. A valve controllably actuated by a solenoid selectively directs a portion of the ink from the pump outlet to the closed container, gradually compressing the air therein as the container is filled. Ink is thereby supplied to the print head at a gradually increasing static pressure, facilitating initiation of production of jet drop streams by the print head.

Abstract: 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.