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 controller controls printing heads to print a page information mark with black ink to perform line flushing. The printing heads each have a plurality of inkjet nozzles for discharging ink being disposed in parallel in a width direction of web paper. Upon printing the mark, when an overlap region is present in which a mark printable region overlaps a line flushing region with ink other than the black ink, the controller performs control to decrease an ink discharge amount per unit area in the overlap region in the mark printable region to be smaller than that in the mark printable region except for the overlap region and the line flushing region. This causes a decreased total ink discharge amount in the overlap region.

A fluid level sensor is configured for identifying a fluid level in a small volume reservoir, such as a fluid reservoir in an ejector head. The reservoir includes a plurality of vertically arranged chambers. A plurality of piezoelectric transducers is distributed over the chambers in a one-to-one correspondence. At least one electrical conductor is electrically connected to each piezoelectric transducer in the plurality of piezoelectric transducers to enable each piezoelectric sensor to receive an electrical signal to a portion of a wall of the chamber to produce an acoustical wave in the chamber and to transmit an electrical signal from each piezoelectric transducer in response to a fluctuating pressure on each piezoelectric transducer produced by the acoustical wave in the chamber.

A liquid droplet ejecting method for ejecting a liquid from at least one ejection hole to form the liquid into liquid droplets, the method including: applying a vibration to the liquid in a liquid column resonance-generating liquid chamber, in which the ejection hole is formed, to form a standing wave through liquid column resonance, and ejecting the liquid from the ejection hole, which is formed in a region corresponding to an antinode of the standing wave, to form the liquid into liquid droplets.

A controller controls printing heads to print a page information mark with black ink to perform line flushing. The printing heads each have a plurality of inkjet nozzles for discharging ink being disposed in parallel in a width direction of web paper. Upon printing the mark, when an overlap region is present in which a mark printable region overlaps a line flushing region with ink other than the black ink, the controller performs control to decrease an ink discharge amount per unit area in the overlap region in the mark printable region to be smaller than that in the mark printable region except for the overlap region and the line flushing region. This causes a decreased total ink discharge amount in the overlap region.

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).

The present invention contains a printing apparatus and a method, e.g., for ejecting inks (i.e. pure liquids, mixtures, colloids, etc.) for a very broad range of physical properties (such as viscosity). Acoustic forces 3a may be generated by an emitter 1 and a reflector 2 to detach droplets 10 from a nozzle 6. The ink may be advanced through the nozzle 6 by a standard back pressure system 5. A reflectorless chamber 7 may enhance acoustic forces 8a and the droplets 10 may be ejected at a bottom 9 of said chamber 7, so that droplets 10 may be deposited on any substrate 11.

Methods of ejecting droplets containing a non-Newtonian fluid by an acoustic droplet ejector can include applying a tone burst of focused acoustic energy to a fluid reservoir containing a non-Newtonian fluid at sufficient amplitude to effect droplet ejection according to a tone burst pattern. The tone burst pattern may include three discrete tone burst segments, the first tone burst segment having greater duration than the second and third segments, and third segment having greater duration than the second segment. The exact durations and amplitudes of the tone burst segments can be tuned to influence the ejection properties.

An electronic circuit for driving an individual print element in a print head is disclosed. The print head comprises an array of print elements, each print element having a piezo-electric actuator that is capable of generating an acoustic wave in an ink chamber of the print element, resulting in the ejection of an ink drop out of a nozzle that is in fluid connection with the ink chamber. The electronic circuit comprises a number of analog drivers for amplifying an output current at a voltage level in-between two source voltage levels, wherein the drivers can be switched into a tristate condition at a voltage level that does not equal one of the source voltage levels.