Liquid negative developer compositions for electrostatic copying containing polymeric charge control agent

A non-amphoteric liquid negative developer composition of improved depletion properties for developing an electrostatic latent image on the surface of an image bearing member, said composition comprising:

• an organic liquid carrier having a resistivity greater than 10.sup.9 ohm-cm and a dielectric constant less than 3;
• thermoplastic resin particles dispersed with said carrier, said particles comprising an intimate admixture of:
• a vinyl polymeric latex, insoluble in said carrier, and including a major amount of monomer units selected from the group consisting of:
• ##STR7## where X is H or CH.sub.3 and Y is C.sub.n H.sub.2n+1, where 1.ltoreq.n.ltoreq.6;
• a pigment;
• a charge control agent, substantially insoluble in the carrier, which imparts a negative charge to the composition and is present in association with the vinyl polymeric latex, said charge control agent consisting essentially of a copolymer of 10-50 parts of butyl vinyl ether and 50-90 parts of a vinyl chloride, the amount of said copolymer included in said composition being substantially less than the amount of said latex;
• and
• a gel for stabilizing said dispersion comprising a vinyl polymer which swells in the presence of said carrier and includes a major amount of monomer units selected from the group consisting of:
• ##STR8## where X is H or CH.sub.3 and Z is C.sub.n H.sub.2n+1, where 8.ltoreq.n.ltoreq.20.

In a method of creating an image, the improvement comprising applying under electrostatic control to an electrostatic image bearing member so as to selectively deposit a coating thereon, a non-amphoteric liquid negative electrostatic developer comprising:

• an organic liquid carrier having a resistivity greater than 10.sup.9 ohm-cm and a dielectric constant less than 3;
• thermoplastic resin particles dispersed within said carrier, said particles comprising an intimate admixture of:
• a vinyl polymeric latex, insoluble in said carrier, and including a major amount of monomer units selected from the group consisting of:
• ##STR9## where X is H or CH.sub.3 and Y is C.sub.n H.sub.2n+1, where 1.ltoreq.n.ltoreq.6;
• a pigment;
• and
• a charge control agent, substantially insoluble in the carrier, which imparts a negative charge to the composition and is present in association with the vinyl polymeric latex, said charge control agent consisting essentially of a copolymer of 10-50 parts of a lower alkyl (C.sub.2 -C.sub.6) vinyl ether and 50-90 parts of a vinyl chloride, the amount of said copolymer included in said composition being substantially less than the amount of said latex.