Toner, developer, and image forming apparatus

A developer comprising:

• a toner comprising a binder resin and a colorant,
• wherein the binder resin has two glass transition temperatures Tg1 and Tg2 in a differential scanning calorimetry at a heating speed of 5° C./min, the glass transition temperature Tg1 is −20° C. to 20° C., and the glass transition temperature Tg2 is 35° C. to 65° C.,
• wherein the binder resin comprises a polyester skeleton and a ring-containing skeleton molecule at ends thereof,
• wherein the binder resin is obtained by block copolymerization of:
• a polyester skeleton A which includes a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure;
• and
• a skeleton B which does not include a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure.

An image forming apparatus, comprising:

• an electrostatic latent image bearing member;
• an electrostatic latent image forming unit, which forms an electrostatic latent image on the electrostatic latent image bearing member;
• a developing unit, which develops the electrostatic latent image using a toner and forms a visible image;
• a transfer unit, which transfers the visible image to a recording medium;
• and
• a fixing unit, which fixes a transfer image transferred to the recording medium,
• wherein the toner comprises a binder resin and a colorant,
• wherein the binder resin has two glass transition temperatures Tg1 and Tg2 in a differential scanning calorimetry at a heating speed of 5° C./min, the glass transition temperature Tg1 is −20° C. to 20° C., and the glass transition temperature Tg2 is 35° C. to 65° C.,
• wherein the binder resin comprises a polyester skeleton and a ring-containing skeleton molecule at ends thereof, and
• wherein the binder resin is obtained by block copolymerization of:
• a polyester skeleton A which includes a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure;
• and
• a skeleton B which does not include a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure.