Ciba-geigy Corporation

Ciba-geigy Ag

Remy Jeanneret

Abul Iqbal

Alain C Rochat

Jin Mizuguchi

Christoph Frey

Gunther Zwahlen

Walter Lang

Georgios Zographos

Anton Kaiser

Compounds of formula (1) ##STR1## wherein A and B are identical or different alkyl, aralkyl or cycloalkyl groups or carbocyclic or heterocyclic aromatic radicals, R.sub.1 and R.sub.2 are hydrogen atoms or substituents which do not impart solubility in water, are particularly suitable as photoconductive substances.

Dithioketo pyrrolopyrroles

Electrophotographic recording material containing selected dithioke

An electrophotographic imaging process, wherein the electrically photosensitive particles for the image reproduction consist of a black pigment selected from the series of the anthraquinoid pigments which contain at least 2 anthraquinone radicals or at least 6 condensed rings, of the perylenetetracarboxylic diimides or of the metal complexes of the formula ##STR1## wherein A represents a nitrogen atom or the ##STR2## X represents a hydrogen or halogen atom or an alkyl group of 1 to 6 carbon atoms,

Electrophotographic imaging process using anthraquinoid black pigments

The invention relates to a dispersion of a water-soluble basic dyestuff in an organic solvent that is at least partially miscible with water or in a mixture of such a solvent with water.

Stable, concentrated dispersions of basic dyestuffs

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Allschwil, Switzerland

Remy Jeanneret