Abstract: An ejection apparatus for ejecting material from a liquid at a plurality of ejection locations (4) disposed in a row, has a plurality of channels (11) through each of which liquid flows in use to or from a respective ejection location at an open end of the channel. An ejection electrode (7) is disposed at each ejection location by means of which an electric field is created in use to cause the ejection of material from the liquid. An electrically conductive path (12) exists to each ejection electrode for supplying a voltage to the ejection electrode (7) in use. The channels (11) are isolated from one another and the electrically conductive paths (12) are separated from the channels over substantially the whole of their length.

Abstract: The invention relates to a method of ejecting material from a liquid within a chamber (5), comprising: controlling the application of first voltage pulses (A) to a first electrode (9) associated with the chamber and second voltage pulses (B) to a second electrode (19) associated with the chamber, such that when a voltage pulse (A) is applied to the first electrode (9) a voltage pulse (B), inverted with respect to the pulse (A) applied to the ejection electrode (9), is applied to the second electrode (19).

Abstract: There is disclosed an ejection apparatus for ejecting material from a fluid. An ejection cell (5) contains fluid from which the material is to be ejected and has an ejection upstand (6) which defines a location from which the material is ejected. One or more ejection electrodes (9) are disposed in the cell substantially surrounding the ejection upstand (6).

Abstract: A nozzle plate apparatus for an inkjet printer has a nozzle aperture (8) which includes a plurality of elements (9) sub-dividing the aperture into a plurality of smaller apertures.

Abstract: A method and apparatus is provided for the generation of agglomerations of particulate material in a liquid. Agglomerations are built up at a point under the effect of an electric field and ejected by electrostatic means. The size of the agglomeration is dependent upon the strength of the electric field, point geometry, the nature of the liquid and the nature of the particles. Agglomerations of particles in the range of from 1 to 500 microns are produced The invention is useful for non-impact printing and other applications where delivery of agglomerations of particles is useful such as in inhalable pharmaceuticals.

Abstract: An apparatus for ejecting material from a liquid has an ejection location 91) with an electrode (3). An electrical potential is applied to the ejection location electrode to form an electric field at the location together; liquid is supplied to the ejection location which contains the particulate material to be ejected from the ejection location. A secondary electrode (5, 8) is disposed adjacent to the ejection location and the voltage on the ejection location electrode is controllable so as to reduce the sensitivity of the head to influence by external electric fields.

Abstract: A deposition material for an electrostatic deposition apparatus such as an ink for an electrostatic ink jet printer, the material comprising a carrier liquid having insulative properties, a charging agent which is soluble in the carrier liquid, and a charge augmenting additive which is soluble in the carrier liquid. The charge augmenting additives are carrier soluble materials that assist in the dissociation of the charging agent. Generally it is found that they are materials which contain nitrogen groups, e.g. amine functionality.

Abstract: An ejection apparatus for ejecting material from a liquid has an ejection cell (2) for containing the liquid in use. The cell (2) has a protrusion (3) disposed so as to be contacted by liquid in the cell on more than one side and defining a predetermined location for a meniscus of the liquid at an opening in the cell. An ejection electrode (6) is disposed in the cell at a position inwardly of the cell with respect to the predetermined location of the meniscus.

Abstract: A process of producing a non-conductive ink formed from colorant particles and a non-conductive carrier liquid where the colorant particles are inherently of a low electrical resistivity. The process includes the steps of applying to the surface of the colorant particles a material with a high electrical resistivity to give the particle a higher surface resistivity and blending the treated colorant particle with the non-conductive carrier to form the non-conductive ink. The insulative material may be selected from polymers, waxes, organic pigments and dye stuffs and the colorant may be carbon black, magnetic iron oxide or metallic powder.

Abstract: A method of depositing material on a surface (136) is described in which a bulk medium (for example ink 122) in the form of a composition of dispersed insoluble material (for example ink particles) and a support medium is supplied to a cell (120). A movement of the insoluble material within the bulk medium is effected towards a transfer aperture (128) within the cell, thereby concentrating the insoluble material within the bulk medium. Thereafter the insoluble material is removed from the concentration within the bulk medium through the aperture (128) and deposited onto the surface (136).

Abstract: The invention concerns an apparatus for generation and ejection into air of discrete agglomerations of a particulate material with a proportion of liquid from a liquid having the particulate material therein. The apparatus defines an ejection location (128) and an electrical potential is applied to the ejection location to form an electric field at the location, and liquid (122) with the particulate material is supplied to the ejection location. An oscillating voltage (A) is applied to the ejection location, the magnitude of the voltage being below that required to cause ejection of particles from the ejection location, and an ejection voltage (B) is superimposed on the oscillating voltage additively with the oscillating voltage in order to cause the sum of the voltages at the ejection location to exceed the threshold required for ejection, when required.

Abstract: A solid ink jet ink composition which is suitable for hot melt applications having a carrier having an electrical resistivity of at least 10.sup.8 Ohm.cm, insoluble marking particles and a particle charging agent dispersed in it. The marking particle may be a pigment, an insoluble dyestuff, a polymer or mixture thereof. The particle charging agent may be a metal soap, a fatty acid, lecithin, an organic phosphorous compound, a succinimide, a sulphosuccinate, petroleum sulphonates, a soluble or partially soluble resin such as a modified rosin ester, an acrylic, a vinyl a hydrocarbon or a mixture thereof. The solid ink jet ink composition may further include a viscosity controller. The ink may be capable of being heated to 155.degree. C. and have at that temperature a viscosity of between 5 to 150 cps.

Abstract: An ink jet ink composition comprising a liquid having an electrical resistance of at least 10.sup.9 Ohm.cm, insoluble marking particles in a range of from 0.5% to 30% by weight and a particle charging agent in a range of from 0.05 to 5% by weight, where the marking particles are capable of being charged and concentrated into agglomerations of the particles and ejected from the ink in the presence of non-uniform electrostatic field of significant gradient in an ink jet printing apparatus.