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: The invention relates to new diazotype materials of which the sensitive layer contains, as a base generator, a compound comprising a basic part and an acid part, the acid part being a 2-carboxycarboxamide group and the basic part consisting of an alkali metal cation or alkaline earth metal cation or a tetraalkylammonium cation.These diazotype materials develop rapidly and possess an excellent resistance to ageing.

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: A tamperproof identification card such as a passport or credit card is provided. A diazo photosensitive composition is intimately mixed with a thermo-adhesive resin and is carefully deposited as a uniformly thin layer in one or more zones on a plastic support material. The zones of the photosensitive compositions are developed to reproduce identifying information such as a photograph, identification number, etc. A plastic protective film is then laminated to the support to protect the identifying information. Since the adhesive resin material is intimately mixed throughout the photosensitive composition, the protective plastic film cannot be removed without destroying the information.

Abstract: An opaque recording material has an opaque sensitive layer which can be transparentized by application of heat or a suitable solvent for the opacifying styrene resin pigment which is dispersed in a polyvinylidene chloride film-forming resin binder. In a particular application, useful for overhead transparencies or for making photographic negatives for reproduction, heat and solvent are both applied to the opaque layer in selected different areas to transparentize the opaque layer. The opaque layer may be deposited on a transparent clear or colored support such as transparent polyester.

Abstract: A film-forming oleophilic photopolymerizable composition is formed from a fluid epoxy resin having an epoxy equivalent of less than 350 and a photosensitive condensation product of a paradiazodiphenylamine fluoroborate and an organic condensation agent. The photopolymerizable compositions can be used as the photosensitive layer of negative lithographic plates, such as printing plates.Acidic aqueous solvent-developable negative lithographic plates are also provided in which the photosensitive layer is formed from a layer of the film-forming oleophilic photopolymerizable composition which is deposited on a hydrophilic support from an organic solvent solution.The lithographic printing plates of the present invention have high mechanical resistance, long shelf-life and can be used in large production runs to make a great number of copies.

Abstract: Montage films, duplicating films, color guide films, microfiche film, color transparencies and similar visual aids are prepared from photosensitive articles having a layer of a photosensitive composition coated on a transparent support, preferably a flexible plastic transparent support.The exposed articles are developable with water to form the visual aid. The photosensitive layer is formed from a composition which includes a photosensitive reaction product of a condensation product of a diazonium compound with an arylsulfonic acid, and an epoxy resin which is liquid at ambient temperatures. The diazonium compound is preferably a paradiazodiphenylamine and the preferred condensing agent is formaldehyde or paraformaldehyde.The photosensitive layer can be colored with a permanent dye of a color depending on the type and use of the visual aid.

Abstract: The invention relates to an improvement in diazocopy development machines. A development chamber is used in which ammonia vapors are generated. A converging system made up of converging walls which accelerate the hot ammonia vapors, without additional means, channels the vapors toward the copy support. Thus, a striking is made of the support with the vapors and the development speed can be significantly increased.