The invention describes a method and apparatus for characterising EHT tripping events and thus discriminating between false trip events and those that warrant the printer being shut down.

A printer (5) operable to print a message in strokes on a substrate (7) passing in a print direction (8) along a moving line (6), wherein the printer is operable (15) to receive an indication of an allowable increase in length in the print direction of a message due to an increase in length in the print direction of gaps between successive strokes printed by the printer, to receive (14) an indication (9) of a speed of movement in the print direction of a moving line, to determine from the indication of the speed of movement of the moving line whether an increase in length in the print direction of a message printed by the printer is greater than the allowable increase in length and, if so, to generate an alert,

A printer (5) operable to print a message in strokes on a substrate (7) passing in a print direction (8) along a moving line (6), wherein the printer is operable (15) to receive an indication of an allowable increase in length in the print direction of a message due to an increase in length in the print direction of gaps between successive strokes printed by the printer, to receive (14) an indication (9) of a speed of movement in the print direction of a moving line, to determine from the indication of the speed of movement of the moving line whether an increase in length in the print direction of a message printed by the printer is greater than the allowable increase in length and, if so, to generate an alert,

A print head of a continuous ink jet printer, including, in a cover: means for producing at least one ink jet; means for separating drops of jets intended for printing from those that do not serve for printing; a slot, enabling drops intended for printing to get out; a recovery gutter (7) for drops not intended for printing, the recovery gutter comprising an ink recovery volume (12); at least one detection conductor (20), arranged inside the head; means (16) for detecting a variation in impedance of at least one of the detection conductors when ink (21) is present in contact with the conductor or with a dielectric layer (22) in contact therewith.

Liquid composition, such as an ink composition, liquid at room temperature, the liquid composition being a liquid composition specifically for printing with a binary deflected continuous jet printing technique wherein the liquid composition forms upon printing drops which are not charged by an electric field, which each have a zero electric charge, which each form a dipole under the effect of an electric field, and then are then deflected by the electric field, characterised in that the liquid composition comprises a solvent comprising one or more organic solvent compound(s) and optionally water, the solvent having globally a dielectric constant less than 15; a binder; one or more dyes and/or pigments; and in that the liquid composition has an electrical conductivity at 20 C. less than or equal to 200 S/cm, preferably less than or equal to 150 S/cm, still preferably less than or equal to 100 S/cm.

Liquid composition, such as an ink composition, liquid at room temperature, the liquid composition being a liquid composition specifically for printing with a binary deflected continuous jet printing technique wherein the liquid composition forms upon printing drops which are not charged by an electric field, which each have a zero electric charge, which each form a dipole under the effect of an electric field, and then are then deflected by the electric field, characterised in that the liquid composition comprises a solvent comprising one or more organic solvent compound(s) and optionally water, the solvent having globally a dielectric constant less than 15; a binder; one or more dyes and/or pigments; and in that the liquid composition has an electrical conductivity at 20 C. less than or equal to 200 S/cm, preferably less than or equal to 150 S/cm, still preferably less than or equal to 100 S/cm.

The invention firstly relates to a print head of a continuous ink jet printer, comprising a first reservoir (12) and a second reservoir (22), arranged on either side of least one jet ejection nozzle (30, 30.sub.1-30.sub.n) to which they are connected, and a first actuator (16, 16.sub.1-16.sub.n) for applying a 1.sup.st pressure to the ink of the, or coming from the, 1.sup.st reservoir, and a second actuator (26, 26.sub.1-26.sub.n) for applying a 2.sup.nd pressure to the ink of the, or coming from the, 2.sup.nd reservoir, and a controller for controlling these first and second actuators, said controller being programmed to apply a variable difference between these 2 pressures.

Embodiments of the invention relate to ink compositions suitable for applications in the printing industry, for example continuous inkjet printing, including ultra-high speed continuous inkjet printing. The ink compositions use volatile C5 ketone (pentanone) solvents (e.g., 2-pentanone, 3-pentanone, or 3-methyl-2-butanone) as a major solvent or the only solvent, and also include a binder resin and a colorant, but preferably contain substantially no acetone, methanol, or methyl ethyl ketone, or other solvents listed on the Japan ISHL class II organic solvents list. Preferred ink compositions can contain up to 30% ethanol, n-propanol, or other solvents not listed on the Japan ISHL class II organic solvents list, but preferably contain substantially no ethanol.

Embodiments of the invention relate to ink compositions suitable for applications in the printing industry, for example continuous inkjet printing, including ultra-high speed continuous inkjet printing. The ink compositions use volatile C5 ketone (pentanone) solvents (e.g., 2-pentanone, 3-pentanone, or 3-methyl-2-butanone) as a major solvent or the only solvent, and also include a binder resin and a colorant, but preferably contain substantially no acetone, methanol, or methyl ethyl ketone, or other solvents listed on the Japan ISHL class II organic solvents list. Preferred ink compositions can contain up to 30% ethanol, n-propanol, or other solvents not listed on the Japan ISHL class II organic solvents list, but preferably contain substantially no ethanol.

The present disclosure provides an inkjet head device for inkjet printers, which includes a tubular base, a composite plate and an inkjet head assembly mounted on the composite plate; the composite plate includes a fiberglass plate and a plastic plate integrally connected to the fiberglass plate, the fiberglass plate is engaged with the open side of the base along an axial direction of the base, the plastic plate is located on a surface facing the base of the fiberglass plate. According to the inkjet head device for inkjet printers of the disclosure, the base plate is a composite plate formed by integrally connecting the fiberglass plate and the plastic plate, where the inkjet head assembly is mounted to form an integrated module, thus the disassembly, the assembly, or the maintenance are convenient.