Toner compositions

1. A toner composition comprising toner particles, wherein the toner particles comprise:

a binder;

a colorant; and

optionally a wax;

wherein the binder comprises a crystalline polyester resin and an amorphous acidic polyester resin,

wherein the amorphous acidic polyester resin has an acid number of from 2.5 to 17 and is a copolyacrylic acid-copolyester resin,

the crystalline polyester resin has an acid number of from 1 to 20, and

the amorphous acidic polyester resin is prepared by reacting a polyacrylic acid homopolymer having a molecular weight of from 500 to 5000 grams/mole, with hydroxyl end groups of a branched polyester resin, wherein the branched polyester is prepared in the presence of a branching agent in an amount of from about 0.1 to about 5 mole % of the resin.

2. The toner composition according to claim 1 , wherein the amorphous acidic polyester resin is a polyester resin that comprises at least one terminal carboxylic acid group.

3. The toner composition according to claim 1 , wherein amorphous acidic polyester resin is a polyester resin that comprises from about 0 to about 1 mol % of an alkyl sulfonated moiety.

4. The toner composition according to claim 1 , wherein the crystalline polyester resin is present in an amount of about 5 to about 35 wt %, relative to a total weight of the binder.

5. The toner composition according to claim 1 , wherein the amorphous acidic polyester resin is present in an amount of about 65 to about 80 wt %, relative to a total weight of the binder.

6. The toner composition according to claim 1 , wherein the amorphous acidic polyester resin has an acid number of from 7 to 15.

7. A process for preparing toner compositions, comprising:

providing an amorphous polyester resin;

acidifying end groups of the amorphous polyester resin to produce a amorphous acidic polyester resin that has a terminal pendant acid group;

preparing toner particles including a colorant, a binder comprising the amorphous acidic polyester resin and a crystalline polyester resin, and optionally a wax; and

preparing a toner composition including the toner particles; wherein the amorphous acidic polyester resin has an acid number of from 2.5 to 17 and is a copolyacrylic acid-copolyester resin prepared by reacting a polyacrylic acid homopolymer having a molecular weight of from 500 to 5000 grams/mole, with hydroxyl end groups of a branched polyester resin, wherein the branched polyester is prepared in the presence of a branching agent in an amount of from about 0.1 to about 5 mole % of the resin, and

the crystalline polyester resin has an acid number of from 1 to 20.

8. The process according to claim 7 , wherein providing the amorphous polyester resin comprises preparing the branched polyester resin by polymerizing a glycol monomer.

9. The process according to claim 7 , wherein providing the amorphous polyester resin comprises preparing the branched polyester resin by polymerizing a glycol monomer in the presence of the branching agent.

10. The process according to claim 7 , wherein the branching agent is chosen from the group consisting of multivalent polyacids, acid anhydrides of multivalent polyacids, lower alkyl esters of multivalent polyacids; multivalent polyols, and mixtures thereof, and trimethylolpropane.

11. The process according to claim 10 wherein the branching agent is trimethylolpropane.

12. The process according to claim 7 , wherein the crystalline polyester resin is present in an amount of about 20 to about 35 wt %, relative to a total weight of the binder.

13. The process according to claim 7 , wherein the amorphous acidic polyester resin is present in an amount of about 65 to about 80 wt %, relative to a total weight of the binder.