Videojet Systems International, Inc.

A.b. Dick Company

Videojet Technologies Inc.

Marconi Data Systems Limited

George W Arway

Frank Eremity

Michael E Stamer

Dilip K Shrivastava

George Murad

Tung M Huang

George H Dick

Joseph James Stone

Elaine Pullen

Joseph M Diebold

According to certain aspects of an embodiment of the present invention, a deflection electrode assembly is provided for use in a continuous ink jet printer of the type which projects a stream of ink drops toward a substrate and controls placement of the ink drops on the substrate by selectively charging the individual ink drops and passing the charged ink drops through an electric (deflection) field created by the deflection electrode assembly. The deflection electrode assembly includes a high voltage deflection electrode and a low voltage deflection electrode positioned on opposite sides of the ink drop stream. A dielectric insulating member is mounted on at least one of the deflection electrodes. The insulating member include a longitudinal opening which exposes the deflection electrode along the path of the ink jet stream, thereby virtually eliminating the tendency for accumulated ink to decrease the strength of the deflection field. The insulating member extends inwardly and underlies the bottom face of the deflection electrode along at least its front and side edges. Providing insulation along the front and side edges of the deflection electrode reduces arcing between the deflection electrodes. Providing the longitudinal opening in the insulating member reduces the field distortion effects of micro-satellite ink drops that would otherwise accumulate on the insulating member.

Ink jet printer deflection electrode assembly having a dielectric insulator

A clean-in-place system for use in an ink jet printhead has a compartment and an end plate with a slot therein to permit ink drops to be projected from the compartment onto a substrate to be marked. For cleaning purposes, a shutter is disposed adjacent the slot to seal it. Thereafter, the pump floods the compartment with ink solvent from a solvent reservoir. The solvent may be agitated by air or a mechanical device. Thereafter, a drain line is used to remove the solvent from the compartment. The pneumatic shutter is reopened after the solvent is withdrawn to enhance the drying of the components. The shutter may consist of an inflatable member and a pump for supplying compressed air to the inflatable member to inflate and deflate it.

Clean-in place system for an ink jet printhead

An ink and solvent supply consists of a dual-chambered container. The lower chamber is provided with make-up solvent, while the upper chamber is provided with ink concentrate. When solvent is required, it is removed directly from the lower chamber. When fresh ink is required, vacuum is applied to the upper chamber causing solvent to pass from the lower chamber to the upper chamber via a conduit, to dilute the ink concentrate to form fresh ink which is then provided to the printing system.

Ink and solvent container for ink jet printers

Flight time of a stream of ink drops is measured and compared against a set point to determine variations therefrom. Variations due to changes in the ink composition are compensated for by adding or withholding solvent in proportion to the detected change. Changes due to variations in nozzle drive voltage result in the computation and use of a new flight time set point value, if necessary to avoid erroneous corrective action.

Ink jet printer employing time of flight control system for ink jet

The printhead of an ink jet printer includes an electrically conductive plastic chassis and charging electrode. The plastic chassis can be constructed of plastic resins such as polyester, nylon, acetal, and polyphenylene sulphide imbedded with electrically conductive fibers such as carbon and stainless steel. The fibers can be coated with nickel to improve the shielding characteristics of the material.

Printhead for ink jet printers

A variable orientation ink catcher for use with ink jet printing equipment receives unused ink drops. The drops are returned to the printing system for reuse. The catcher includes an arcuate receiving portion offset from an outlet port. Caught ink flows by gravity from the receiving portion via a reservoir to the outlet port through a wide range of angular orientations.

Variable orientation ink catcher

A drop deflection device suitable for use in a drop marking system employs an electret. Electrically conductive marking drops such as inks are given an electrical charge. The drops pass between a pair of deflections plates at least one of which is formed by an electret (a dielectric material which has been subjected to corona discharge to create a relatively permanent electrically charged material body). Depending upon the presence or absence of a charge on a particular drop, it will be deflected by the field between the plates on to a substrate for marking. If uncharged, the drops continue to a collection device which returns them to the ink reservoir.

Drop deflection device and method for drop marking systems

A valve is disclosed suitable for use in ink marking systems. The valve has an output port, a supply port, and a control port. The control port communicates with a chamber disposed above a flexible diaphragm while the output port communicates with a reservoir to be periodically supplied with fluid. The diaphragm flexes between an open position permitting the supply port to communicate with the output port and a closed position blocking such communication as a function of the pressure differential across the diaphragm created by pressure changes at the central port.

Valve for liquid marking systems

A method and apparatus are disclosed for providing feedback control of the ink drop velocity in a drop marking system. The control system maintains essentially constant velocity of the ink drops as they pass through a deflection field which causes certain of the electrically conductive drops to be directed onto a substrate to be marked. The ink flow between two selected points is monitored by a control device to generate ink flow rate data and compared against a reference value. In the event that a flow rate deviation is sensed, appropriate action is taken to change the flow rate. Such action includes altering ink viscosity and/or ink pressure.

Ink drop velocity control system

A fast acting ink valve adapted to be used in conjunction with the nozzle of an ink jet printing system is disclosed. A flexible diaphragm modulates flow through a valve chamber. A spring biases the diaphragm to a sealed position to prevent flow. Ink pressure in the marking system unseals the diaphragm permitting flow. Unlike check valves, the invention has minimal pressure drop due to the location of the bias spring outside the ink flow path.

Ink valve for marking systems

An ink return system for an ink jet printer which directs a portion of the ink projected from a nozzle to a print surface and the remainder to a catcher, the catcher having a receptacle entrance for intercepting the ink stream including a tube with an entrance to catch the ink stream and then convey the ink liquid along a flow path away from the catcher and a cowling adjacent the receptacle connected to a vacuum source to create a scavenging air flow at the tube entrance for ingesting ink mist without exposing the intercepted liquid ink to the relatively high rate of air flow necessary to sweep away the ink mist.

Low evaporation ink catcher for ink jet printing system

A system for controlling the flow of pressurized liquid to a head, for example the print-head of an ink jet printing system, through an elastic conduit and including an outer conduit to form a pressurizable jacket surrounding the inner conduit extending between the head and a remotely located liquid flow control valve, the jacket being depressurized by operation of a valve utilizing a controller simultaneously with closure or shut-off of the liquid flow control valve to prevent dribbling or drooling of liquid at the head immediately following shut-off.

Remote ink valve

A system for printing with ink droplets each having a known quantity of ink which system has a hydraulic portion including a main ink supply, a supplemental ink supply and a recirculating droplet generating print head and an electronic portion which includes a character generator for electrically characterizing each of the droplets so that they are directed either to a print target or to a dump and a monitoring means for identifying the droplets assigned to strike the print target and controls in the hydraulic portion for permitting a metered additional quantity of ink, depending on the number of print target directed droplets counted, to flow from the supplemental ink supply to the main ink supply, thus, allowing use of a standard ink formulation in the supplemental ink supply.

Drop counter ink replenishing system

In an ink jet printing system, there is provided an arrangement whereby the ink, which is not used in printing, may be returned to the reservoir from which it was withdrawn, together with fresh ink, in a manner so that ink pressure fluctuations, together with shutdowns for filling the reservoir are avoided.

Noninterrupt ink transfer system for ink jet printer

A vacuum return ink system for an ink jet printing apparatus includes an ink/air separator comprising a housing having a chamber formed therein. A first inlet port of relatively large diameter connects the chamber via a short tube of similar diameter to the ink catcher of the printing apparatus used for accumulating unused ink. A second port of relatively large diameter is provided to connect the chamber via a tube of a similar diameter to a vacuum source. A third port of relatively small diameter is provided to connect the chamber via a tube of similar diameter to an evacuated ink return tank. A tubular section defining the third port is inserted into the housing with the end thereof extending to the floor of the chamber. Ink and air are drawn from the catcher into the chamber via the first port at a high rate of flow, thereby minimizing a buildup of ink at the catcher mouth. The ink having a higher inertial mass than the air is carried by gravity to the chamber floor where it is drawn into the small diameter tubular section and carried at a relatively low flow rate to the evacuated ink return tank, thereby minimizing solvent evaporation of the ink. The air flowing into the chamber from the catcher is carried therefrom to the vacuum source via the second port.

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River Grove, IL, United States of America

George W Arway