METHOD FOR ADJUSTING TONER DENSITY SENSOR, AND MAGNETIC MEMBER FOR ADJUSTING SENSITIVITY OF TONER DENSITY SENSOR

摘要

PROBLEM TO BE SOLVED: To sharply reduce the dispersion of toner density for every developing device, and to improve reliability of the developing device and productivity at the job site by making a magnetic member having a thickness thicker than the developer layer passing above the toner density sensor in the developing device abut on a head surface of the toner density sensor thereby adjusting the sensor. ;SOLUTION: The toner density sensor 3 senses the change of magnetic permeability by the change of the mixing ratio of carriers and the toner to the two component developer consisting of magnetic carriers and the organic fine powder toner and converts it into an electric signal. At the time of adjusting sensitivity for the toner density sensor 3, the sensitivity adjustment of the toner density sensor 3 is performed in the state of abutting a head surface 3a of the toner density sensor on a magnetic member 4. The magnetic member 4 adopted in this case is the member obtained by hardening the mixture of ferrite and rubber, whose thickness (t) is thicker than the developer layer passing above the toner density sensor 3 inside the developing device 1 being actually adopted. In such a manner, the dispersion of the toner density for every developing device 1 is reduced.;COPYRIGHT: (C)1998,JPO