In an inkjet printer of the present invention, an air blowing outlet is formed around a slit through which ink droplets pass in a cap of a head cover, and air is blown toward a printing object from the blowing outlet. The air blowing outlet is formed independent of the slit, and the direction in which the air is blown is substantially parallel to the flight direction of ink droplets, and thus hardly any blown air meets the ink droplets that have passed through the slit and are flying toward the printing object. On the other hand, ink particles that have rebounded off the printing object are repelled by the air blown from the blowing outlet, and thus the amount of ink particles entering the head cover via the slit is suppressed.

In an inkjet printer of the present invention, an air blowing outlet is formed around a slit through which ink droplets pass in a cap of a head cover, and air is blown toward a printing object from the blowing outlet. The air blowing outlet is formed independent of the slit, and the direction in which the air is blown is substantially parallel to the flight direction of ink droplets, and thus hardly any blown air meets the ink droplets that have passed through the slit and are flying toward the printing object. On the other hand, ink particles that have rebounded off the printing object are repelled by the air blown from the blowing outlet, and thus the amount of ink particles entering the head cover via the slit is suppressed.

A device for forming and ejecting drops of an ink jet of a CIJ printing machine, this device including: a cavity for containing an ink and including an end provided with a nozzle (10) for ejecting ink drops, actuator means (21, 22, 32, 41, 42), in contact with the cavity, in which device the jet velocity modulation, from the nozzle (10), has a value Vj(f.sub.t) at the operating frequency of the cavity and the actuator, and this jet velocity modulation, at the temperature of 15 C. and at the temperature of 35 C., does not vary, in a frequency range of 5 kHz about the operating frequency f.sub.t, outside the range of between 0.25 Vj(f.sub.t) and 4 Vj(f.sub.t).

A device for forming and ejecting drops of an ink jet of a CIJ printing machine, this device including: a cavity for containing an ink and including an end provided with a nozzle (10) for ejecting ink drops, actuator means (21, 22, 32, 41, 42), in contact with the cavity, in which device the jet velocity modulation, from the nozzle (10), has a value Vj(f.sub.t) at the operating frequency of the cavity and the actuator, and this jet velocity modulation, at the temperature of 15 C. and at the temperature of 35 C., does not vary, in a frequency range of 5 kHz about the operating frequency f.sub.t, outside the range of between 0.25 Vj(f.sub.t) and 4 Vj(f.sub.t).

A continuous ink jet print head (10), including: an ink droplet generator (116) configured to emit an ink droplet (158) along an undeflected droplet flight path (30); a charge electrode (118) configured to impart a charge to the ink droplet; deflector plates (120A, 120B) adjacent the undeflected droplet flight path, downstream from the charge electrode, and configured to deflect the ink droplet to a deflected droplet flight path that lies within a range of deflected flight paths bounded by at least deflected droplet flight path and a most deflected droplet flight path; a gutter (122) configured to receive an ink droplet traveling along the undeflected droplet flight path; and an ink buildup sensor (102) configured to detect an accumulation of ink (140) relative to a droplet flight path disposed within the range of deflected flight paths.

A continuous ink jet print head (10), including: an ink droplet generator (116) configured to emit an ink droplet (158) along an undeflected droplet flight path (30); a charge electrode (118) configured to impart a charge to the ink droplet; deflector plates (120A, 120B) adjacent the undeflected droplet flight path, downstream from the charge electrode, and configured to deflect the ink droplet to a deflected droplet flight path that lies within a range of deflected flight paths bounded by at least deflected droplet flight path and a most deflected droplet flight path; a gutter (122) configured to receive an ink droplet traveling along the undeflected droplet flight path; and an ink buildup sensor (102) configured to detect an accumulation of ink (140) relative to a droplet flight path disposed within the range of deflected flight paths.

A removable single-block assembly for an ink circuit of a continuous inkjet printer, including a plate having a plurality of fluid inlets and a plurality of fluid outlets, this assembly further including a first pump called a pressure pump, a second pump called a recovery pump, and a filter, fluid connection means to allow fluids to flow: between said fluid inlets, the first or second pumps, and said fluid outlets, and means for mounting and dismounting the assembly on the ink circuit.

A removable single-block assembly for an ink circuit of a continuous inkjet printer, including a plate having a plurality of fluid inlets and a plurality of fluid outlets, this assembly further including a first pump called a pressure pump, a second pump called a recovery pump, and a filter, fluid connection means to allow fluids to flow: between said fluid inlets, the first or second pumps, and said fluid outlets, and means for mounting and dismounting the assembly on the ink circuit.

A filter module (38) for a continuous inkjet printer (10) comprising a filter housing (40) and a filter medium (42) fixed within the housing (40). The filter housing (40) further includes an inlet portal (44) through which ink flows into the housing under pressure and a first self-sealing valve assembly (54) disposed within the inlet portal. In addition, housing includes an outlet portal (46) through which ink flows out of the housing (40) under pressure and a second self-sealing valve assembly (56) disposed within the outlet portal (46). The first and second valve assemblies (54, 56) open when mechanically connected to an ink flow path (34) from an ink tank (18) to a print head (14), and the first and second valve assemblies (54, 56) seal closed when mechanically disconnected from the ink flow path (34).

A filter module (38) for a continuous inkjet printer (10) comprising a filter housing (40) and a filter medium (42) fixed within the housing (40). The filter housing (40) further includes an inlet portal (44) through which ink flows into the housing under pressure and a first self-sealing valve assembly (54) disposed within the inlet portal. In addition, housing includes an outlet portal (46) through which ink flows out of the housing (40) under pressure and a second self-sealing valve assembly (56) disposed within the outlet portal (46). The first and second valve assemblies (54, 56) open when mechanically connected to an ink flow path (34) from an ink tank (18) to a print head (14), and the first and second valve assemblies (54, 56) seal closed when mechanically disconnected from the ink flow path (34).