Electrophotographic developer, developer cartridge, process cartridge, and image forming apparatus

An electrophotographic developer comprising:

• a toner that includes toner base particles and an external additive attached to a surface of the toner base particles, an amount of Al on the surface of the toner base particles being from about 0.002 atm % to about 0.02 atm %;
• and
• a carrier that includes magnetic particles and a coating resin layer that coats the magnetic particles, the coating resin layer including organic particles with a volume-average particle diameter of from about 80 nm to about 800 nm or inorganic particles having an organic layer on a surface of the inorganic particles with a volume-average particle diameter of from about 80 nm to about 800 nm, the carrier satisfying one of the following formulas, SP1 representing a solubility parameter of a resin of the coating resin layer, SP2 representing a solubility parameter of the organic particles, and SP3 representing a solubility parameter of the organic layer:
• about 10>|SP1−SP2|>about 4 (1);
• and
• about 10>|SP1−SP3|>about 4 (2).