DEVELOPING DEVICE, IMAGE-FORMING DEVICE, AND PROCESS CARTRIDGE

PROBLEM TO BE SOLVED: To provide a developing device which stably and accurately detects the concentration of a toner in a developer in the device itself, and to provide an image-forming device equipped with the developing device and a process cartridge. SOLUTION: In the developing device 4, a feed-conveying path 9 is provided above a stir-conveying path 10. Furthermoe, a feeding aperture part 91, which is an aperture part making the stir-conveying path 10 communicate with the feed-conveying path 9, is provided in a position in the vicinity of the end part, on the downstream side in a developer-conveying direction, in the stir-conveying path 10. A toner concentration sensor 201, which is a toner concentration-detecting part, is arranged, on the downstream side in the developer-conveying direction, in the stir-conveying path 10. COPYRIGHT: (C)2010,JPO&INPIT