Detection of developer density

Abstract

Abstract PURPOSE:To prevent deterioration in the accuracy of detecting developer density owing to a stained light transmittable window for detecting toner density provided in the outside wall part of a developing device by cleaning periodically said window by a magnetic brush which rotates together with agitating vanes. CONSTITUTION:A light transmittable window 30 is provided in the position in a developing device 24 where the developer agitated by agitating vanes 27 is visible well. A photoelectric detector 33 is disposed on the outside flank thereof. Light is irradiated from a light source 31 of the detector 33 through the window 30 to the developer in the developing device during the operation of the developing device and the light reflected from the developer is detected by a photodetector 32 by which the toner density is detected. A magnet 34 is provided in a part at the top end of the vanes 27 and a magnetic brush 35 formed by said magnet rubs periodically the window 30 according to the rotation of the vanes 27. Since the window 30 is cleaned in such a way, the window is not stained by the toner and the toner density is detected with high accuracy.

Inventors

• 👤 Shigeru Nakayama
• 👤 茂 中山

Bibliographic Details