Abstract: The invention relates to a process and a device for developing a latent image formed on a magnetic surface, by means of a magnetic developing powder, in order to form a powder image.The device contains means (2) for causing the powder (4) to flow onto the magnetic surface (1) uninfluenced by a magnetic field other than that of the magnetic surface (1). These means can consist of magnetic means (3) for taking the powder (4) from a trough (5), means (6) for detaching the powder (4) from the magnetic means (3), and means (7) for bringing the powder (4) into the vicinity of the magnetic surface (1).This developing device can be used in a printing apparatus containing means for transferring a powder image onto a substrate.

Abstract: A reversed development electrophotographic reproduction process for developing a charge image on a photoconducting support using a single component magnetic developer provides copies with improved densities of the dark regions, better definition and less contamination of the background. This is accomplished by connecting each of the photoconductor surface, the magnetic means for transferring the magnetic development powder from a supply source to the charge image to thereby form the powder image, and the conducting support to which the powder image is transferred to at least one voltage generator via the terminal having the same polarity as that of the charge on the photoconductor surface. Thus, for a positively charged selenium alloy photoconducting surface, the photoconductor, magnetic means, and conducting support are each connected to the positive terminal of preferably a single voltage generator. Apparatus for carrying out the process is also provided.

Abstract: This invention provides a process of electrographic reproduction onto an arbitary support, whereby an image of a magnetic, monocomponent developing powder is transferred, under the influence of electrical means, onto a support covered with a thin layer of volatile dielectric liquid having a volume resistivity greater than 10.sup.3 ohm-cm.sup.2 /cm.

Abstract: The sharpness and contrast of reversed images obtained by pressure-fixation of electrostatically developed copies of negative transparencies is provided by dissipating the electrostatic latent image after the development step but before the pressure-fixing step. The process finds application in microfilm reader/reproduction devices.

Abstract: A dry development device for reproduction machines, wherein the device includes a rotating magnetic brush for distributing development powder on an image support. The image support is advanced on a planar surface which has an opening therein positioned beneath the magnetic brush. The opening has a plurality of wires stretched thereacross, which hold the image support against the brush, while allowing any development powder which might otherwise adhere to the back of the image support to fall into the opening. The wires are arranged in two groups of parallel, uniformly spaced wires with the wire groups converging and positioned symmetrically in a herringbone pattern. A scraper edge of the toner reservoir is presented against the magnetic brush at an angle substantially perpendicular to the surface of the brush.