Addressograph Multigraph Corporation

John D Blades

Jerome E Jackson

Shou L Hou

An ion modulator having a bias electrode is capable of producing copies in which the contrast and background are controllable. Such modulator functions in a process which utilizes an adjustable charge density applied to set up uniform fringing fields of the desired magnitude which block ions directed towards background (light) areas. Funneling fields are set up in image (dark) areas in opposition to the original fringing fields by simultaneous imaging and ion projection, decreasing the effect of such fringing fields and permitting ions to pass through the modulator in image areas.

Ion modulator having bias electrode for regulating control fields

A duplicating apparatus is equipped with a photoconductive modulator screen cylinder for making reproductions of a graphic original on a dielectric receiving medium utilizing aperture-controlled electrostatic printing techniques. Means is provided for creating a charge distribution system on the surface of the modulator corresponding to an image to be reproduced from the graphic original. The apparatus also comprises charging means for projecting gas ions against the modulator screen cylinder, electrode means for collecting the gas ions selectively transmitted by the modulator screen cylinder on the dielectric receiving medium and means for developing the dielectric receiving medium to create a visible image.

Duplicating apparatus employing modulator screen cylinder

The invention is an improved modulator, in the form of a screen, having the capability of selectively passing therethrough charged particles, such as gas ions, in accordance with a pattern that corresponds to the image and non-image areas of a graphic original. The apertured modulator is formed from a metal screen, such as a 200 mesh wire screen, having a wire cross section of 0.051 millimeter and is overcoated with a four-micron thickness of a photoconductor, such as selenium or an organic photoconductor, over which is next applied an equal thickness of an insulating layer, such as polystyrene. The three-layered modulator constructed in this manner is imparted a charge pattern corresponding to the graphic subject to be reproduced by the creation of a charge distribution system (CDS) on the insulating surface. The CDS created on the modulator in the environment of this invention is completely passive to electromagnetic radiation. The modulator is placed between an emission electrode and collection electrode to selectively pass therethrough gas ions to be received onto a dielectric surface in a charge pattern corresponding to the graphic subject from which the charge distribution system was created on the insulating layer. The technique and procedure whereby such a developable charge image is created on a dielectric material, such as a sheet of paper, involves disposing the modulator, bearing its charge distribution system, in the environment of an arrangement of electrodes which includes a corona emission electrode juxtaposed with the metal side of the modulator for creating gas ions in air which are directed into the apertures of the modulator and a collection electrode disposed on the side opposite facing and immediately juxtaposed with the insulating surface for directing the ions toward a sheet of dielectric paper in contact with the collecting electrode.

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Chagrin Falls, OH, United States of America

John D Blades