Liquid developer for electrostatic photography

Abstract

A liquid developer for electrostatic photography is disclosed. The liquid developer comprises resin grains dispersed in a non-aqueous solvent having an electric resistance of at least 10.sup.9 .OMEGA. cm and a dielectric constant of not higher than 3.5, wherein the dispersed resin grains asre copolymer resin grains obtained by polymerizing a solution containing at least one kind of a mono-functional monomer (A) which is soluble in the non-aqueous solvent but becomes insoluble in the non-aqueous solvent by being polymerized, in the presence of a dispersion-stabilizing resin which is soluble in the non-aqueous solvent and is a comb-like copolymer comprising at least (1) a mono-functional macromonomer (M) having a weight average molecular weight of from 1.times.10.sup.3 to 2.times.10.sup.4 and (2) a monomer represented by the general formula (III) described below, the mono-functional macromonomer (M) comprising at least one polymer component corresponding to a repeating unit represented by the general formula (IIa) or (IIb) described below and at least one polymer component containing at least one polar group selected from --COOH, --PO.sub.3 H.sub.2, --SO.sub.3 H, --OH, ##STR1## wherein R.sub.1 represents --R.sub.2 or -OR.sub.2 (wherein R.sub.2 represents a hydrocarbon group)), --SH, a formyl group and an amino group, and the monofunctional macromonomer (M) having a polymerizable double bond group represented by the general formula (I) described below bonded to only one terminal of the main chain thereof; ##STR2## wherein X.sub.0 represents --COO--, --OCO--, --CH.sub.2 OCO--, --CH.sub.2 COO--, or --O--, --SO.sub.2 --, --CO--, ##STR3## wherein R.sub.11 represents a hydrogen atom or a hydrocarbon group), and a.sub.1 and a.sub.2, which may be the same or different, each represents a hydrogen atom, a halogen atom, a cyano group, a hydrocarbon group, --COO--Z.sub.1 or --COO--Z.sub.1 bonded via a hydrocarbon group (wherein Z.sub.1 represents a hydrogen atom or a hydrocarbon group); ##STR4## wherein X.sub.1 has the same meaning as X.sub.0 in the general formula (I); Q.sub.1 represents an aliphatic group having from 1 to 22 carbon atoms or an aromatic group having from 6 to 12 carbon atoms; b.sub.1 and b.sub.2, which may be the same or different, have the same meaning as a.sub.1 and a.sub.2 in the general formula (I); and V represents --CN, --CONH.sub.2, or ##STR5## (wherein Y represents a hydrogen atom, a halogen atom, an alkoxy group or --COOZ.sub.2 (wherein Z.sub.2 represents an alkyl group, an aralkyl group, or an aryl group)); ##STR6## wherein X.sub.2 has the same meaning as X.sub.0 in the general formula (I); Q.sub.2 has the same meaning as Q.sub.1 in the general formula (IIa); and d.sub.1 and d.sub.2, which may be the same or different, have the same meaning as a.sub.1 and a.sub.2 in the general formula (I), with the proviso that, in the component of the mono-functional macromonomer (M) represented by the general formula (II) and in the component of the monomer represented by the general formula (III), at least one of Q.sub.1 and Q.sub.2 represents an aliphatic group having from 10 to 22 carbon atoms.