Abstract: A modular ink circulation system for effecting ink flow, in a continuous ink jet printer, from the ink reservoir to the print head and from the print head back to the reservoir. The system comprises, e.g.: (i) an ink supply module including pump, heater and filter that are removable from the printer as a unit; (ii) an ink return module including a pressure transducer, an ink defoaming reservoir and an ink flow-control solenoid that are removable from the printer as a unit; and (iii) a vacuum module including an air pump, an air pressure regulator and an ink collector reservoir that are removable from the printer as a unit.

Abstract: In a continuous ink jet printing apparatus, an ink circulating system allows maintenance of the ink supply reservoir at approximately atmospheric pressure while providing for positive withdrawal of ink from the catcher and/or print head outlet of the apparatus. The system is operable with a single pump. To achieve such positive withdrawal of ink, elements are provided in a bypass line extending from the supply pump outlet to the atmospheric region of the ink reservoir or in the passage from that region of the ink reservoir to the pump intake line, for generating a region(s) of sub-atmospheric pressure, and such region(s) are coupled to the catcher and/or print head outlet.

Abstract: An ink jet printer includes a fluid supply system for supplying ink through the print head of the printer. The fluid supply system includes a pump arrangement supplying ink to the print head from a supply tank via a fluid supply line. A plurality of ink return lines are connected between the pump outlet and the pump inlet. Each of the ink return lines includes a flow restriction, with the flow restriction in each line providing a fluid flow impedance which differs from the impedances provided by the other flow restrictions. A valve arrangement connects the pump outlet to selected ones of the ink return lines, to provide means for controlling the flow rate of ink supplied through the ink supply line to the print head. During periods in which the printer is shut down, a substantially reduced ink flow through the print head is continuously maintained at a reduced fluid flow rate and at a reduced fluid pressure.

Abstract: An ink supply system for supplying ink through the print head of an ink jet printer includes a pump arrangement supplying ink to the print head from a supply tank and, further, plural ink return lines connected between the pump outlet and the pump inlet. Each of the ink return lines includes a flow restriction, with the flow restriction in each line providing a fluid flow impedance which differs from the impedances provided by the other flow restrictions. A valve arrangement controls the connection of the pump outlet to a selected one of the ink return lines, such that the flow rate of ink through the ink supply line to the print head is effectively controlled.

Abstract: An ink jet printing apparatus for printing addresses on documents being transported along an independently operated conveyor. The printing apparatus includes a control console, a printing arm telescopically received within the console, and an ink jet printing head mounted on a carriage which is vertically movable within the printing arm. A tachometer wheel is mounted on the printing carriage for contacting a document being transported past the printing head and generating a tachometer signal in response thereto. A programmed microprocessor generates printing control signals in synchronism with the tachometer signal.

Abstract: An ink jet printer for depositing ink drops from a plurality of jet drop streams on a print receiving medium includes a print head which generates a plurality of jet drop streams, such streams being positioned in at least one row. The drops are selectively charged and, thereafter, pass adjacent a deflection electrode which extends parallel to and to one side of the row of jet drop streams. A drop deflecting electrical potential is applied to the deflection electrode to produce a drop deflection field which directs the drops into print and catch trajectories. A catcher extends parallel to the row of jet drop streams and on the opposite side of the row from the deflection electrode. The catcher is positioned directly opposite the deflection electrode and receives drops in the catch trajectories, while permitting the drops in the print trajectories to strike the print receiving medium.

Abstract: An ink jet printing apparatus for printing addresses on documents being transported along an independently operated conveyor. The printing apparatus includes a control console, a printing arm telescopically received within the console, and an ink jet printing head mounted on a carriage which is vertically movable within the printing arm. A tachometer wheel is mounted on the printing carriage for contacting a document being transported past the printing head and generating a tachometer signal in response thereto. A programmed microprocessor generates printing control signals in synchronism with the tachometer signal.