Imaging system

A finely divided particulate toner composition comprising a colorant and an amorphous, low-melting copolyester exhibiting a softening temperature of at least about 45.degree. C., fusing at temperatures ranging from about 100.degree. C. to about 130.degree. C. and exhibiting a resistivity of at least about 10.sup.15 ohm--cm., wherein the copolyester contains within the polymer chain at least about 30 mole percent of at least one divalent radical selected from the group consisting of:

• a. an arylene radical having no center of symmetry represented by the formula:
• ##STR11## wherein [AR] is an arylene radical containing from 6 to about 18 carbon atoms, R is selected from the group of radicals consisting of hydrogen, alkyl containing from 1 to about 4 carbon atoms, halo, sulfo and alkali metal salts thereof, nitro, cyano lower alkoxy, amino, thio lower alkoxy and --N(R')p wherein each R' can be independently hydrogen or lower alkyl and p is an integer of 2 or 3, each m is independently a number from 0 to 1 and n is a number from 0 to 3, and
• b. an alkylene radical having no center of symmetry represented by the structural formula:
• ##STR12## wherein R" is an alkyl radical containing from 1 to about 4 carbon atoms, each R"' is independently hydrogen or R", q is a number from 1 to about 10 and each r is independently a number from 0 to 1;
• and when the radical having no center of symmetry is at least about 30 mole percent of said arylene, the remaining comonomers of the copolyester consist essentially of at least two comonomers selected from the group consisting of aromatic, aliphatic and combinations thereof, and when the radical having no center of symmetry is at least about 30 mole percent of said alkylene, the remaining comonomers of the copolyester consist essentially of at least about 20 mole percent aromatic comonomer and at least one additional comonomer selected from the group consisting of aromatic, aliphatic and combinations thereof.

A finely divided particulate toner composition comprising a colorant and an amorphous, low-melting copolyester exhibiting a softening temperature of at least about 45.degree. C., fusing at temperatures ranging from about 100.degree. C. to about 130.degree. C. and exhibiting a resistivity of at least about 10.sup.15 ohm -- cm.), wherein the copolyester contains within the polymer chain at least one divalent radical selected from the group consisting of:

• a. an arylene radical having no center of symmetry and selected from the group consisting of arylene dicarboxy radicals, arylene dioxy radicals and mixtures thereof, and
• b. an alkylene radical having no center of symmetry and selected from the group consisting of alkylene dioxy radicals, alkylene dicarboxy radicals and mixtures thereof;
• at least two additional comonomers capable of reacting with the arylene radical of (a) or the alkylene radical of (b) to form the copolyester;
• and
• when the arylene radical is the divalent radical, the at least two additional comonomers are selected from the group consisting of aliphatic diols, aromatic diols, aliphatic diacids, aliphatic diesters, aromatic diacids, aromatic diesters, anhydrides of aromatic diacids, and mixtures thereof, and when the alkylene radical is the divalent radical, the copolyester comprises at least 20 mole percent of an aromatic comonomer selected from the group consisting of aromatic diacids, the anhydrides of the aromatic diacids, the acid chlorides of the aromatic diols and mixtures thereof and at least one additional comonomer selected from the group consisting of alkylene dioxy radicals, alkylene dicarboxy radicals, aromatic diacids, aromatic diesters, the anhydrides of the aromatic diacids, the acid chlorides of the aromatic diacids, aromatic diols, the salts of the aromatic diacids and mixtures thereof.