Abstract: Inkjet printer apparatus includes a pressure-regulated tank having an inlet connected to an ink reservoir, and an outlet connected to a printhead including nozzles for discharging continuous streams of ink drops towards a substrate for printing thereon and gutters for intercepting the ink drops not to be printed. The apparatus further includes a bypass line between the tank outlet and the ink reservoir, a bypass control valve for controlling the flow rate via the bypass line enabling the flow rate to be preset during draining of the tank, and a pump controllable to enable pre-calibrating the pump during filling of the tank.

Abstract: A method and apparatus for printing a desired pattern on a substrate by discharging continuous streams of liquid ink drops from nozzles towards the substrate, and selectively charging the liquid ink drops with multi-level charges deflecting them different amounts. Some of the liquid ink drops are thus directed to different locations on the substrate for printing the desired pattern thereon, while other liquid ink drops not to be printed are intercepted by a gutter before reaching the substrate. At least some of the liquid ink drops to be printed being either uncharged or charged with a multi-level charge of one polarity, while all the liquid ink drops not to be printed are charged with a charge of the opposite polarity. Each stream of ink drops discharged from a nozzle is illuminated with stroboscopic light at the same frequency as the drop formation, and the illuminated stream is optically sensed on the fly for determining various conditions, including ink velocity, X-axis offset and Y-axis offset.

Abstract: A method and apparatus for inkjet printing by means of a plurality of inkjet nozzles arranged in at least one row and having spaced, parallel nozzle axes for emitting liquid ink drops towards the substrate, and multi-level charging and deflecting plates controlled to deflect individual drops to selected locations on the substrate with respect to the respective nozzle axis according to the pattern to be printed. The multi-level charging and deflecting plates are controlled to cover, for each nozzle, a line section which includes two non-contiguous deposit zones to receive ink drops from the respective nozzle, separated by a non-deposit zone not to receive ink drops from the respective nozzle.

Abstract: Inkjet printer apparatus includes a pressure-regulated tank having an inlet connected to an ink reservoir, and an outlet connected to a printhead including nozzles for discharging continuous streams of ink drops towards a substrate for printing thereon and gutters for intercepting the ink drops not to be printed. The apparatus further includes a bypass line between the tank outlet and the ink reservoir, a bypass control valve for controlling the flow rate via the bypass line enabling the flow rate to be preset during draining of the tank, and a pump controllable to enable pre-calibrating the pump during filling of the tank.

Abstract: A method of reducing print-density variations in printers, particularly multi-deflection continuous-jet printers, including printing elements arrayed along the X-axis for printing on a substrate moving relative to the printing elements along the Y-axis. The method includes controlling the printer to print a test pattern having a plurality of strips extending along the X-axis, wherein the gray-level of each printed strip is the same along the X-axis, but varies from one strip to the next along the Y-axis; analyzing the printed test pattern to detect gray-level variations in the printed strips; preparing a density correction table of gray-level corrections for each X-coordinate; and controlling the printing elements in accordance with the density correction table to reduce the detected gray-level variations.

Abstract: Ink jet printing apparatus includes a linear array of jet modules each having an inlet for receiving ink, an outlet for re-circulating the ink, a nozzle for discharging ink in the form of droplets, and a perturbation device for causing a continuous stream of ink droplets to be discharged from the respective nozzle. The apparatus further includes an ink supply system having an inlet manifold, an outlet manifold, and a plurality of connecting passageways connecting the jet modules in parallel between the inlet and outlet manifolds. The connecting passageways connect the inlet of each jet module to the inlet manifold and the outlet of each jet module to the outlet manifold, such as to define a T-connection of each jet module with the inlet and outlet manifolds. Such a construction reduces the mass of each jet module thereby permitting printing at higher frequencies and with smaller ink droplets.

Abstract: A method and apparatus for printing a desired pattern on a substrate by discharging continuous streams of liquid ink drops from nozzles towards the substrate, and selectively charging the liquid ink drops with multi-level charges deflecting them different amounts. Some of the liquid ink drops are thus directed to different locations on the substrate for printing the desired pattern thereon, while other liquid ink drops not to be printed are intercepted by a gutter before reaching the substrate. At least some of the liquid ink drops to be printed being either uncharged or charged with a multi-level charge of one polarity, while all the liquid ink drops not to be printed are charged with a charge of the opposite polarity. Each stream of ink drops discharged from a nozzle is illuminated with stroboscopic light at the same frequency as the drop formation, and the illuminated stream is optically sensed on the fly for determining various conditions, including ink velocity, X-axis offset and Y-axis offset.

Abstract: A method and apparatus for printing a desired pattern on a substrate by discharging continuous streams of liquid ink drops from nozzles towards the substrate, and selectively charging the liquid ink drops with multi-level charges deflecting them different amounts. Some of the liquid ink drops are thus directed to different locations on the substrate for printing the desired pattern thereon, while other liquid ink drops not to be printed are intercepted by a gutter before reaching the substrate. At least some of the liquid ink drops to be printed being either uncharged or charged with a multi-level charge of one polarity, while all the liquid ink drops not to be printed are charged with a charge of the opposite polarity. Each stream of ink drops discharged from a nozzle is illuminated with stroboscopic light at the same frequency as the drop formation, and the illuminated stream is optically sensed on the fly for determining various conditions, including ink velocity, X-axis offset and Y-axis offset.

Abstract: A method and apparatus for inkjet printing by means of a plurality of inkjet nozzles arranged in at least one row and having spaced, parallel nozzle axes for emitting liquid ink drops towards the substrate, and multi-level charging and deflecting plates controlled to deflect individual drops to selected locations on the substrate with respect to the respective nozzle axis according to the pattern to be printed. The multi-level charging and deflecting plates are controlled to cover, for each nozzle, a line section which includes two non-contiguous deposit zones to receive ink drops from the respective nozzle, separated by a non-deposit zone not to receive ink drops from the respective nozzle.

Abstract: A continuous jet module, apparatus, and method are described for printing with a high viscosity printing fluid having a viscosity of 10 to 100 centipoise. The module includes a housing having a printing fluid reservoir for feeding the high viscosity printing fluid to a plurality of channels. The reservoir has a first longitudinal direction and includes a plurality of openings in a second direction. Each channel is disposed in one of the corresponding openings, and each channel receives the high viscosity printing fluid from the reservoir through its corresponding opening and generates therefrom a continuous jet of high viscosity printing fluid.

Abstract: A method and apparatus for sensing improper operation of an ink jet printer having a plurality of nozzles each emitting, towards a substrate, a series of ink drops broken-off from a continuous ink jet filament, and selectively charging and deflecting said drops according to a pattern of marks to be printed by a respective nozzle on the substrate by: controlling the plurality of nozzles to print test marks on a test strip including a plurality of marks for each nozzle produced by a series of drops from the nozzle while at different charge levels: sensing the test marks for each nozzle; analyzing the test marks for all the nozzles for proper operation of the ink jet printer; and producing an output signal indicating errors in the operation of the printer.

Abstract: A continuous jet module for discharging a high viscosity printing fluid and apparatus which includes a plurality of the printing modules is provided. The module includes a housing having a printing fluid reservoir for storing and providing said high viscosity printing fluid and a plurality of channels. The reservoir has a first longitudinal direction and includes a plurality of openings in a second direction. Each channel is disposed in one of the corresponding openings and each channel receives the high viscosity printing fluid from the reservoir through its corresponding opening and generates therefrom a continuous jet of high viscosity printing fluid.