Toner, developer, image forming apparatus, and process cartridge

A toner comprising a polyester resin, the polyester resin including;

• a polyester resin component A insoluble in tetrahydrofuran;
• and
• a polyester resin component B soluble in tetrahydrofuran,
• wherein the toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., measured at a first temperature rising in differential scanning calorimetry (DSC), and satisfies the following formulae (1) and (2):
• T=1/{a/(TgA+273)+b/(TgB+273)}−273 (1)
• T−TgAB>30×a (2)
• wherein a and b represent weight ratios of the polyester resin component A and the polyester resin component B to a total weight of the polyester resin component A and the polyester resin component B, and satisfy the equation a+b=1;
• and TgA, TgB and TgAB represent second glass transition temperatures (Tg2nd), measured at a second temperature rising in differential scanning calorimetry, of the polyester resin component A, the polyester resin component B, and a mixture of the polyester resin component A and the polyester resin component B, respectively.