Abstract: Carrier beads for use in an electrostatographic developer mixture comprise a glass core or iron-containing metal core enveloped with a coating of a copolymer of N-vinylcarbazole, trialkoxyvinylsilane and/or triacetoxyvinylsilane and optionally one or both of the monomers of the group consisting of C.sub.1 -C.sub.4 alkyl (meth)acrylate and styrene.

Abstract: A recording material suited for the photographic production of a conductivity pattern, wherein said material contains a recording layer applied to the surface of a support the surface resistance of which is at least 100 times as small as that of the recording layer and wherein said recording layer contains in intimate admixture:I. at least one ultraviolet radiation-sensitive organic polyhalogen compound from which photolytically halogen-containing free radicals can be separated,Ii. a photoconductive polymer containing N-vinylcarbazole units andIii. as sensitizing agent increasing the conductivity of the recording layer during its photo-exposure an acylamino compound corresponding to the following general formula:R.sub.1 -- CO -- NH -- R.sub.2wherein:R.sub.1 represents an alkyl group or a cycloalkyl group, andR.sub.2 represents an aromatic group.

Abstract: A toner material for use in the development of electrostatic charge patterns is described which comprises carbon black as coloring material, polystyrene as thermoplastic resin binder and at least one diester of orthophthalic or metaphthalic acid that is solid at room temperature as plasticizer, wherein the polystyrene binder has a molecular weight comprised between about 30,000 and about 70,000, the proportion by weight of the carbon black to the binder is comprised between about 5:100 and about 20:100, and the proportion by weight of the said plasticizer(s) to the binder is comprised between about 2:100 and about 15:100. The toner material is of a very simple and inexpensive composition and nevertheless has optimum photographic and physical properties.