Abstract: An orifice plate assembly for use in continuous ink jet printers includes a linear orifice plate having formed therein at least one linear array of orifices extending from a first end region to a second end region. The orifice plate has a main body portion which tapers gradually in thickness (t) along the length of the plate from the first end region to the second end region. The orifice plate is mounted so as to have an effective width (w) which tapers from the first to second end region. The relation t.div.w remains approximately constant along its length dimension.

Abstract: In a continuous ink jet printer, the ink pressure is adjusted by detecting the fractional charge imparted to satellite drops, and adjusting the ink pressure as a function of the detected charge.

Abstract: There is described an acoustic absorber for an ink jet printer using a waveguide to generate ink drops. The absorber comprises a sheet of elastomer disposed on the orifice plate between the orifice plate and the charge plate of the printer, and a diffuser disposed in contact with the elastomer and between the elastomer and the charge plate, the diffuser having an acoustic impedance of at least 3.times.10.sup.7 kg/m.sup.2 sec. The length and width of the elastomer sheet and the diffuser are such as to absorb the vibrations from the orifice plate and prevent reflections at the end of the waveguide.