Ion projection copier

Claim 1

A fluid jet-assisted ion projection copier characterized by comprising a charge receptor, means for projecting incremental images of dark and illuminated areas of an original to be copied, means for projecting ions upon said charge receptor in accordance with said projected incremental images of dark and illuminated areas of said original, said means for projecting ions including an ion generator and a source of transport fluid for driving ions out of said ion generator through an exit channel defined by a pair of walls, and modulation means adjacent said exit channel for controlling the passage of ions therethrough, said modulation means comprising: a. a first source of potential connected to one of said walls, b. a light collector through which said images of dark and illuminated areas are projected, c. optically switchable means located to receive light from said light collector and including first conductive means, second conductive means and photoconductive means sandwiched between said first and said second conductive means, and wherein said second conductive means forms the other of said walls, d. a second source of potential, substantially identical to said first source of potential, electrically connected to said second conductive means, e. a source of reference potential, different from said first and second potentials, connected to said first conductive means, whereby when portions of said optically switchable means are dark, corresponding portions of said other wall maintain said second potential and when portions of said optically switchable means are illuminated, corresponding portions of said other wall maintain said reference potential.