GB1515938A - Xerographic toner carrier - Google Patents

Abstract

1515938 Donor construction for xerographic apparatus XEROX CORP 9 Dec 1975 [3 Feb 1975 (2)] 50416/75 Heading B2L A donor for the type of xerographic apparatus wherein a photoconductor is image-wise exposed at B, developed at C and the image transferred at D comprises an endless support member 24 adapted to pick up charged toner particles 28 and transport them to station C, said donor having a plurality of electrically conductive elements 32 separated and mutually isolated by dielectric material 34 and means for establishing a plurality of electrostatic microfields between elements 32; as shown, said means may comprise two brushes 50 and 52 of opposite polarity past which conductive tabs 38, 40 and 42, 44 respectively pass during rotation of drum 24a, whereby the potential of elements 32 alternates continuously; the larger potential applied to drum 10 at station C overcomes the electrical attraction of the particles 28 to drum 24, and they are thus coated on to the drum. Alternative forms of conductive elements may be provided by (1) winding the drum with 2 wires, either (a) helically or (b) longitudinally (2) providing a drum of a stack of circular conductive plates separated by dielectric or (3) making a drum of 2 helical conductive springs between common end plates and separated by a helical insulating member (see Figs. 3-22, not shown). In case 1(a) above, a helical insulating cord may be wound in between or seated on the wires so as to protrude thereabove, giving automatic spacing from drum 10; similarly the insulating member in (3) above may be raised to perform this function. Drum 24 may be resilient, e.g. an inflated drum, to allow for irregularities in drum 10.