in a elektrophotographischen entwicklungsstation entwicklerüberwachungsvorrichtung

摘要

PURPOSE:To reduce the effect of external conditions by detecting the deterioration condition of the developer itself. CONSTITUTION:A detecting vessel 11 is formed by a non-magnetic guide plate 11 and part of developing vessel bottom plate 2, and the sensitive element 12 formed by resin-molding 16 a flatly wound electric coil 15 together with terminals 17a, 17b is disposed in its inside. As a result of this, the magnetic brush 3a by developer 3 is formed by the revolution of a sleeve 6 and develops the latent images of a recording drum 22, after which part of the magnetic brush 3a is scraped off from the outside peripheral surface of the sleeve 6 by a guide plate 10 and is led into the detecting vessel 11 where it causes the inductance of the electric coil 15 to change in correspondence to its concentration, and while doing this it is discharged by the revolution of a roll magnet 13. Based on the inductance change of the electric coil 15, a metering valve 21 is rotation-controlled so that the toner 19 is replenished into the developer 3 so as to maintain the toner concentration within a fixed range.