Negative solid block toner

Claim 1

A negatively chargeable solid toner composition comprising resin particles, pigment particles and charge enhancing additive, the additive being selected from the group consisting of block polymers of the type AB, BAB, ABA, wherein B is a segment that is compatible with the resin particles, the monomer units of said A segment, when homopolymerized, having a polarity which is higher than the polarity of the monomer units of said B segment when homopolymerized, (a) A is one or two blocks which comprise about from 0.1 to 50% by weight of the copolymer, having a number average molecular weight of about from 200 to 10,000 and prepared from at least one monomer selected from compounds of the general formula CH 2 ═CCH 3 CO 2 R or CH 2 ═CHCO 2 R, wherein R is hydrogen, in which case adjacent carboxylic groups can be dehydrated to form anhydride units, or R is an inorganic or organic cation or R is an alkyl group of 1-20 carbon atoms where at least 2 pendant moieties in the block at the terminal end of R are of the general formula --SO 2 R 1 or --SO 2 NHR 1 , wherein R 1 is an aryl group or an alkyl group of 1-20 carbon atoms, and (b) B is one or two blocks which are the balance of said copolymer, having a number average molecular weight of about from 500 to 100,000 and prepared from monomers selected from styrene, substituted styrene, butadiene or compounds of the general formulas CH 2 ═CCH 3 CO 2 R' and CH 2 ═CHCO 2 R', wherein R' is alkyl of 1-20 carbon atoms.