Liquid-projection method and device for high-resolution printing in a continuous ink-jet printer

A high-resolution printing device in a vibrationally excited continuous ink-jet printer comprising:

• a pressurized ink container provided with at least one nozzle for ejection of an ink let in a direction of an axis of propagation of said jet;
• means for vibrationally exciting the jet so as to obtain a point of break-up into ink drops in a vicinity of an electrostatic charging device connected to a supply circuit said electrostatic charging device providing electrostatic charging of the ink drops;
• a detector connected to a circuit for processing information that has been picked up by the detector, sad detector being placed in the vicinity of the ink drops after their electrostatic charging by the charging device;
• a gutter for the recovery of the drops not used for printing;
• wherein the charging device comprises a single electrode creating an electrical field that is asymmetrical with respect to the axis of the ink jet;
• and
• wherein the charging electrode takes the form of two half-planes intersecting each other in a direction parallel to the axis of the ink jet.

A high-resolution ink-jet printer comprising:

• a pressurized ink container (3) having a nozzle for ejection of an ink jet in a direction of an axis of propagation of said jet;
• an electrostatic charging device (7, 8) located down stream from said jet and spaced apart from said jet axis;
• a circuit (3, 4) vibrationally exciting the jet so as to break-up the jet into ink drops in a vicinity of the electrostatic charging device (7);
• said electrostatic charging device providing electrostatic charging of the ink drops in pairs of drops with a first drop of each pair being charged to a voltage V.sub.m higher than the Rayleigh voltage, and a second drop of said pair being charged to a voltage V.sub.c lower than the Rayleigh voltage;
• and said device (7, 8) comprises an electrode (7) creating an electrical field that is asymmetrical with respect to the axis of the ink jet for deflecting said charged ink drops;
• a detector (9) connected to a circuit (10) for processing information that has been picked up by the detector, said detector being located in the vicinity of the ink drops after their electrostatic charging by the charging device;
• and
• a gutter for the recovery of the drops not used for printing;
• and
• whereby said first drop throws off a charged satellite drop due to said charge V.sub.m of said first drop;
• and said asymmetrical field initially deflects said charged drops;
• and said second drop further deflects said satellite drop of said first drop in accordance with the charge on said second drop.