Resin particles, method of producing resin particles, toner, toner storage unit, and image forming apparatus

Resin particles, each comprising:

• a binder resin,
• wherein the binder resin includes a biomass-derived resin, and polyethylene terephthalate or polybutylene terephthalate,
• an amount A of a biomass-derived component of the biomass-derived resin and
• an amount B of the polyethylene terephthalate or the polybutylene terephthalate satisfy A>B,
• each of the resin particles has a core-shell structure including a shell layer and a core layer,
• an average thickness of the shell layer is from 100 nm to 500 nm;
• wherein the shell layer comprises an amorphous polyester resin;
• and
• wherein the biomass-derived resin comprises the amorphous polyester resin, and an acid component of the amorphous polyester resin comprises plant-derived sebacic acid.