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 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 0.25Vj(f.sub.t) and 4Vj(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 0.25Vj(f.sub.t) and 4Vj(f.sub.t).

A makeup fluid is added to an ink liquid of an inkjet printer to reduce the viscosity of the ink liquid, the makeup fluid including a fluorescent color material in a solvent. An inkjet printer apparatus employing a makeup fluid is provided with a makeup fluid tank to which a light-emitting element and a light-receiving element are attached, and detects the presence or absence of the makeup fluid by irradiating ultraviolet light from the light-emitting element, causing visible light to be emitted from the fluorescent color material in the makeup fluid, and detecting the visible light with the light-receiving element.

A makeup fluid is added to an ink liquid of an inkjet printer to reduce the viscosity of the ink liquid, the makeup fluid including a fluorescent color material in a solvent. An inkjet printer apparatus employing a makeup fluid is provided with a makeup fluid tank to which a light-emitting element and a light-receiving element are attached, and detects the presence or absence of the makeup fluid by irradiating ultraviolet light from the light-emitting element, causing visible light to be emitted from the fluorescent color material in the makeup fluid, and detecting the visible light with the light-receiving element.

A fluid ejection device is provided with a valving element adapted to reciprocate in the containing chamber to thereby push the fluid out from the ejection port, and then block the ejection port with a tip part. The containing chamber is provided with a communication port for accepting the fluid pressure-fed from a supply section. In the case in which the valving element is located at a predetermined stopping position, a internal space of the containing chamber is divided by a boundary part, which is formed of a part of the valving element and a part of the containing chamber having contact with each other, into a first space including a part of the space between the ejection port and the communication port, and a second space in which the communication port opens.

A fluid ejection device is provided with a valving element adapted to reciprocate in the containing chamber to thereby push the fluid out from the ejection port, and then block the ejection port with a tip part. The containing chamber is provided with a communication port for accepting the fluid pressure-fed from a supply section. In the case in which the valving element is located at a predetermined stopping position, a internal space of the containing chamber is divided by a boundary part, which is formed of a part of the valving element and a part of the containing chamber having contact with each other, into a first space including a part of the space between the ejection port and the communication port, and a second space in which the communication port opens.

In an ink for an inkjet printer of an electrostatic charging control type, the ink including a resin, a pigment, a conductive agent, and a solvent, for the resin, one that contains carboxyl groups or hydroxyl groups is used. Thus, an ink print applied to a material including a large quantity of a plasticizer can be made stable over a prolonged period of time without subjecting the ink print to an ultraviolet irradiation or other special treatments.

In an ink for an inkjet printer of an electrostatic charging control type, the ink including a resin, a pigment, a conductive agent, and a solvent, for the resin, one that contains carboxyl groups or hydroxyl groups is used. Thus, an ink print applied to a material including a large quantity of a plasticizer can be made stable over a prolonged period of time without subjecting the ink print to an ultraviolet irradiation or other special treatments.

A continuous-type inkjet ink composition includes a polyvinyl butyral resin (Resin 1) and a rosin ester resin (Resin 2), and organic solvents, wherein the content of Resin 1 in the inkjet ink composition is 1.0 to 8.0 percent by mass, and the content ratio of Resin 1 and Resin 2 satisfies Resin 1:Resin 2=20:1 to 10:8 based on ratio by mass, and the total quantity of organic solvents regulated by industrial health and safety regulation is 5 percent by mass or less in the inkjet ink composition. The composition demonstrates excellent discharge stability and jetting property as well as excellent adhesion to various types of base printing materials including polyolefin films with no surface treatment.