Toner compositions containing as a negative charge-controlling agent a mixture of ortho-benzoic sulfimide and para-anisic acid

摘要

A dry, negatively charged electrostatic toner compsn. comprises particles of a polyester resin of Tg 50-100 deg C and of average mol.wt. 20,000-100,000. A charge controlling agent of 0.1-10 wt.% based on resin of a 1:1 mixt. of o-benzoic sulphimide (I) and p-anisic acid (II) is included. Also claimed are a developer compsn. in which the toner component is as specified above and the carrier component comprises particles having cores (pref. metallic, more pref. ferromagnetic, most pref. Sr ferrite) coated with a polymer comprising polymethyl methacrylate or a copolymer of p-t-butylstyrene and a 1-4C alkyl methacrylate; and also a method of developing an electrostatic latent image using the disclosed developer.