Method and apparatus for toner cake delivery

Abstract

An imaging system for effecting electrostatic printing of an image, wherein the imaging system includes at least one contact electrostatic printing engine operable in a novel fashion upon a copy substrate, for imaging and development of a latent image representative of the image, and subsequent transfer of the developed image to the copy substrate. The developed image is created by separating and selectively transferring portions of a high solids content secondary toner cake layer in correspondence with the image and non-image regions of the latent image. A toner cake layer delivery apparatus draws from a supply of high solids content liquid developing material to form a primary toner cake layer on a receiving surface of a receiving member. The primary toner cake layer is subject to uniform charging to a first polarity followed by an induced charge of a second, opposing polarity to a selectable depth. The primary toner cake layer is brought into pressure contact at a process nip with an electrically-biased donor surface of movable coating member. Separation of the donor surface and the receiving surface causes the primary toner cake layer to be separated into inner and outer layers. The outer layer is transferred to the donor surface and the inner layer remains on the receiving surface. The inner layer may then be used as the secondary toner cake layer, which features a high solids content, a uniform thickness, and an accurately metered mass per unit area.