Abstract: A system and method for applying electrically charged non-magnetic toner to an image device, and subsequently to a moving substrate, provides precise level control, proper control of the electrical charge of the toner, minimization of dusting problems, and maximum evenness of the toner layer. First and second fluidized toner beds have the toner in them charged using corona sources. The second bed maintains a level of toner above the level in the first bed, and a spillway-defining restraining dam is disposed between the beds so that the toner above the level desired in the second bed spills over the restraining dam into the first bed, allowing very precise control of the level of toner in the second bed. Toner transfer mechanisms (such as rotating conductive cylinders) transfer toner from the first bed to the second bed, and from the second bed to the image device. Scrapers scrape excess toner from the rotating cylinders so that it falls back into either the first or second bed.

Abstract: A specified and designated, non-primary color print (imaging) is applied to a substrate (paper) by mixing at least first and second differently colored toner particles having substantially uniform physical characteristics, and introducing them in desired proportions into a fluidized bed. The toner powders are uniformly mixed together in the fluidized bed (as by using rotors in addition to applying fluidizing air to the bed), and then a substantially uniform electrostatic charge (e.g. about +6.5-+8 kV D.C., which can be applied by blades on the rotor) is applied to the bed, and then the electrostatically charged mixture of toner particles is applied to the substrate, to image uniform non-primary color symbols on the substrate. The uniform physical characteristics of the powders are size (the vast majority of particles having a size between about 5 microns and about 25 microns), a resistivity of greater than 10.sup.12 ohm-cm, and a flowability between a predefined minimum and maximum.

Abstract: A toner composition for developing an electrostatic latent image comprising a base toner, which is a blend of a polymeric resin and a colorant, and one or more of a lubricating agent, a flowability agent, a charge-stabilizing agent, and a conductive agent, which has certain electrical characteristics. The base toner has a mean particle diameter (D.sub.50) of 7 to 18 microns, and a bulk resistivity of greater than 10.sup.12 ohm-cm. The toner composition is prepared by blending a polymeric resin with a colorant and then blending a dry powder lubricating agent, and optionally other additives, with the base toner. The toner composition is charged by being disposed in an electrostatic fluidized bed from which the toner particles are levitated by air and then subjected to field charging created by a high voltage corona generating device contained within the bed.

Abstract: A security document is produced from a paper substrate having invisible hydrophobic toner blended into the paper. The clear toner is produced by milling and classifying a polyester resin, mixing it with silica flowing agent, and then electrostatically imaging the toner onto the paper substrate, as a spot that can be overprinted, or preferably as indicia that is not visible to the naked eye or color copiers. An infra-red absorbing or UV responsive dye may be added to the toner so that it is visible under infra-red/ultraviolet light respectively, or without that dye it is not visible when eliminated by light of any wavelength. When applied to the paper the toner is snow white, but after infra-red heat fusing it blends into the paper and is substantially invisible.