Low fusing temperature tone powder of crosslinked crystalline and amorphous polyesters

A process for preparing a polymer for a low fusing temperature toner powder comprising the steps of:

• (a) admixing;
• (1) about 25 to about 75 weight percent of a low molecular weight, crystalline polyester that has been esterified with pyromellitic dianhydride and has the formula:
• ##STR9## and has a glass transition temperature in the range of about -20.degree. to about 60.degree. C., a melting temperature in the range of about 60.degree. to about 120.degree. C., a number average molecular weight in the range of about 1,500 to about 5,000 and a weight average molecular weight in the range of about 3,000 to about 10,000, and containing about 2 carboxyl groups per molecule;
• (2) about 25 to about 75 weight percent of a low molecular weight, amorphous polyester that has been esterified with pyromellitic dianhydride and has the formula:
• ##STR10## and has a glass transition temperature in the range of about 50.degree. to about 90.degree. C., a number average molecular weight in the range of about 1,500 to about 5,000 and a weight average molecular weight in the range of about 3,000 to about 10,000, and containing about 2 carboxyl groups per molecule;
• (3) about 2 to about 10 weight percent of a low molecular weight epoxy novolac resin that has the formula:
• ##STR11## and has an epoxy functionality of about 4.8;
• and (4) about 0.5 to about 4 weight percent of a crosslinking catalyst;
• and
• (b) melt blending said mixture at a temperature in the range of about 90.degree. to about 180.degree. C.