Developing device and image forming apparatus

摘要

The developing device includes: a developing container that stores a developer including a nonmagnetic toner and a magnetic carrier; a toner bearing member that bears the toner and conveys the toner to a developing portion; and a separating portion wherein a surface of the toner bearing member includes a plurality of recess structures in which a smallest opening width R is equal to or larger than r t10 and equal to or smaller than r c10 , and a depth D is equal to or larger than r t10 /2, where r t10 is a particle diameter in which an accumulated number distribution in a toner granularity distribution is 10%, and r c10 is a particle diameter in which an accumulated number distribution in a carrier granularity distribution is 10%; and a percentage of the recess structures per unit area in a toner bearing region of the toner bearing member is equal to or larger than 55%.