Electrostatographic suspension developer and a process for its preparation comprising quaternary ionic copolymer for positive toner charge

Claim 1

An electrostatographic suspension developer containing a dispersed pigment and at least one ionic copolymer to produce a positive toner charge in an electrically insulating carrier liquid having a volume resistivity of at least 10 9 ohm.cm and a dielectric constant below 3, characterized in that the copolymer is formed from cationic monomers in which the cations of the monomers correspond to the following general formulae ##STR31## in which R 1 is a hydrogen atom or a CH 3 -group, R 2 is a C 1 -C 18 hydrocarbon radical, R 3 and R 4 may be the same or different and represent a C 1 -C 18 hydrocarbon radical or together form a 5- or 6-membered ring, R 5 is a hydrogen atom or a C 1 -C 18 hydrocarbon radical, X is one of the groups ##STR32## and Y represents the atoms required to complete a 5- or 6-membered heterocyclic ring, and the anions of the cationic compounds correspond to the following general formulae ##STR33## in which Z is one of the groups --SO 3 o or ##STR34## R 2 and R 3 each represent a C 1 -C 18 hydrocarbon radical R 6 is a C 6 -C 24 hydrocarbon radical, R 7 is one of the groups --COOR 6 or --SO 2 R 6 , R 8 and R 9 may be the same or different and represent one of the groups --CN, --CO 2 , --halogen, --COOR or --SO 2 R, R 10 has the same meaning as R 6 or is a --COOR 6 group, R 11 is one of the groups --CN or --COOR and R 12 , R 13 and R 14 may be the same or different and represent a hydrogen atom or the groups --CN, --R or --COOR, R is a C 1 -C 24 hydrocarbon radical.