COLOR SELECTION BY MIXING PRIMARY TONERS

摘要

A specified and designated, non-primary color print(imaging) is applied to a substrate (paper) by mixing atleast first and second differently colored toner particleshaving substantially uniform physical characteristics, andintroducing them in desired proportions into a fluidizedbed. The toner powders are uniformly mixed together inthe fluidized bed (as by using rotors in addition toapplying fluidizing air to the bed), and then asubstantially uniform electrostatic charge (e. g. about+6.5-+8 kV D.C., which can be applied by blades on therotor) is applied to the bed, and then theelectrostatically charged mixture of toner particles isapplied to the substrate, to image uniform non-primarycolor symbols on the substrate. The uniform physicalcharacteristics of the powders are size (the vast majorityof particles having a size between about 5 microns andabout 25 microns), a resistivity of greater than 10 12ohm-cm, and a flowability between a predefined minimum andmaximum. When utilizing the fluidized bed as according tothe invention, slight changes in chemical composition ofthe toners may be easily accommodated without change inthe resulting uniform imaging.