Metal salts of beta-diketones as charging adjuvants for electrostatic liquid developers

A process for preparing electrostatic liquid developer for electrostatic imaging comprising

• (A) dispersing at an elevated temperature in a vessel a thermoplastic resin and a dispersant nonpolar liquid having a Kauri-butanol value of less than 30, and optionally a colorant, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the dispersant nonpolar liquid degrades and the resin and/or colorant decomposes,
• (B) cooling the dispersion, either
• (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid;
• (2) with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid;
• or
• (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid;
• (C) separating the dispersion of toner particles having an average particle size of less than 30 .mu.m from the particulate media;
• (D) adding to the dispersion a nonpolar liquid soluble ionic or zwitterionic charge director compound;
• and
• (E) adding during any of steps (A), (B), (C) or (D) a metal salt of the general formula:
• ##STR5## where M is a metal cation;
• R and R.sup.1 which can be the same or different are alkyl of 1 to 18 carbon atoms, substituted alkyl of 1 to 18 carbon atoms, aryl of 6 to 30 carbon atoms, or substituted aryl of 6 to 30 carbon atoms;
• n is the valency of the metal;
• J is 0 to n-1;
• and
• X.sup.- is OH, Cl, F, sulphate, nitrate, chlorate, phosphate, acetate, alkyl carboxylate of 1 to 18 carbon atoms, or aryl carboxylate of 6 to 30 carbon atoms.