Sublistatic Holding S.a.

Dieter Hendriks

Wolfgang Mehl

Robert Decombe

Developers consisting of virtually spherical particles made by spray drying an aqueous dispersion of a magnetic substance and a coating material consisting of polymers or waxes or of a mixture of polymers with a wax and/or a plasticizer, their constituents being preferably water-dispersible, and process for their preparation.

Magnetic developers and process for their preparation

Dry developer for the development of electrophotographic latent images, consisting of a single type of very fine particle containing an electrically conductive substance, a magnetic substance and a binder, characterized in that it has a high conductivity, greater than 10.sup.-2 Siemens cm, and in that this conductivity is independent of the value of the electrical field applied and its use in a process for development of electrophotographic latent images wherein it is applied from an insulating surface.

Magnetic toners and development process

The present invention relates to electrophotography, and in particular to the formation of a permanent image in one or more colors from latent electrostatic images which correspond to the color separations of an original and the developing of which is effected by means of a developer composed of polymer particles containing at least one dyestuff which can sublime or vaporize at between 100.degree. and 250.degree. C. The recording is effected under dry conditions by vaporization or sublimation of the dyestuffs present in the developers, without any fixing operation following the transfer of the dyestuffs onto the support which receives the recording.

Process for formation of permanent image

An electrophotographic developer is composed of particles comprising magnetic cores which are coated with an organic substance and at least one dyestuff which passes into the vapour state at a temperature in the range of from 100.degree. to 220.degree. C. at atmospheric pressure.

Electrophotographic developers containing sublaminate dyes

Developers containing a polymer and at least one sublimable or vaporizable dyestuff which, at atmospheric pressure, passes into the vapor state at between 100.degree. and 220.degree. C., and characterized in that they consist of particles containing a mixture of at least one polymer with a plasticizer or a wax, which release the vapors of said dyestuff if heated at the sublimation or vaporization temperature of said dyestuff, and process for their preparation.

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Geneva, Switzerland

Dieter Hendriks