Liquid developer for electrostatic photography

Claim 1

A liquid developer for electrostatic photography comprising a carrier medium having an electrical resistivity of not less than 10 9 Ω·cm and a dielectric constant of not more than 3.5 having dispersed therein at least a resin, wherein said resin is a copolymer resin obtained by copolymerizing (1) a solution containing at least one copolymer having an unsaturated bond obtained by copolymerizing at least one monomer (A) represented by formula (I) shown below and at least one monomer (B) represented by formula (II) shown below, and reacting the resulting copolymer with at least one monomer (C) represented by formula (III) shown below, (2) at least one monomer (D) which is soluble in the carrier medium but becomes insoluble upon polymerization, and (3) at least one monomer (E) represented by formula (IV) shown below to obtain a resin dispersion: ##STR15## wherein a 1 , a 2 , a 3 , b 1 , b 2 , b 3 , d 1 , d 2 , d 3 , e 1 , e 2 , and e 3 , which may be the same or different, each represents a hydrogen atom, a hydrocarbon group, --CO 2 J or --CH 2 CO 2 J, wherein J represents a hydrogen atom or a hydrocarbon group; X, Y, V and Z, which may be the same or different, each represents --O--, --S--, --CO--, --CO 2 --, --OCO--, --SO 2 --, --CH 2 OCO--, --CONH--, --SO 2 NH--, --NHCO--, --NHCONH--, ##STR16## wherein W represents a hydrocarbon group or --R 2 --T 1 ) m (R 3 --T 2 ) n U; L and F, which may be the same or different, each represents a hydrocarbon group or a chemical bond linking X and Q, or V and G, respectively, either directly or via a hetero atom; Q and G, which may be the same or different, each represents a group selected from --CO 2 H, ##STR17## --COCl, --OH, --NH 2 , --NHR 4 , wherein R 4 represents a hydrocarbon group, or --NCO, Q and G thus being capable of forming a chemical bond upon reaction; R 1 represents a hydrocarbon group having from 4 to 20 carbon atoms; U represents a hydrogen atom, an unsubstituted hydrocarbon group having up to 18 carbon atoms or a hydrocarbon group having up to 18 carbon atoms which may be substituted with a halogen atom, --OH, --CN, --NH 2 , --CO 2 H, --SO 3 H or --PO 3 H; T 1 and T 2 , which may be the same or different, each represents --O--, --S--, --CO--, --CO 2 --, --OCO--, --SO 2 --, ##STR18## --NHCO 2 -- or --NHCONH--, wherein U 1 , U 2 , U 3 , U 4 , and U 5 each has the same meaning as U; R 2 and R 3 , which may be the same or different, each represents a substituted or unsubstituted hydrocarbon group having up to 18 carbon atoms which may contain in its main chain a group ##STR19## wherein T 3 and T 4 , which may be the same or different, each has the same meaning as T 1 and T 2 ; R 5 represents a substituted or unsubstituted hydrocarbon group having up to 18 carbon atoms; U 6 has the same meaning as U; and p represents 0 or an integer of from 1 to 4; and m and n each represents 0 or an integer of from 1 to 4.