Patent ID: 8041270

Claim:
An image developer using a one-component developer, comprising: a developing roller configured to visualize an electrostatic latent image formed on an image bearer with a pulverized toner; and a feed roller configured to feed the pulverized toner to the developing roller while contacting thereto, wherein the pulverized toner comprises: a parent toner; a wax; and an external additive comprising an additive having a number-average particle diameter of from 20 to 60 nm and adhering to the surface of the parent toner at an adherence strength of from 50 to 70%, and wherein the following relationships (1) to (3) are satisfied: 4.70<Log 10 R<5.70 (1) 8.00<Log 10 Z<10.70 (2) −6.25*Log 10 R+ 37.5<Log 10 Z<− 6.25*Log 10 R+ 45.6 (3) wherein R represents a resistivity of the developing roller and Z represents an impedance of the pulverized toner.