Patent ID: 6104892
Filing Date: 2000-08-15
Classification: G03G

Abstract:
A developing device having:(a) a developer bearing member for bearing thereon a developer having toner and carrier and conveying the developer to a developing area;(b) an agitating member for agitating said developer, a rotation radius R (m) of said agitating member being 5.0.times.10.sup.-3 (m).ltoreq.R.ltoreq.8.0.times.10.sup.-3 (m); and(c) density detecting means for detecting a density of the toner in said developer, said density detecting means detecting any change in the density of the toner as a change in a magnetic permeability of said developer:wherein when a shortest distance between an outermost surface of said agitating member and a detecting surface of said density detecting means is defined as Dmin (m) and a half length of the detecting surface of said density detecting means in a plane perpendicular to a rotary axis of said agitating member is defined as r, 0 (m)<Dmin.ltoreq.1.0.times.10.sup.-3 (m) and 0.4.ltoreq.r/R.ltoreq.0.75.