ELECTROPHOTOGRAPHIC PRINTER

摘要

PROBLEM TO BE SOLVED: To constitute a system which suppresses toner density variation due to environmental changes without making the composition of toner and carriers complicated. SOLUTION: An output characteristic of a sensor which detects toner density variation of a magnetic two-component developer as magnetic permeability variation by a magnetic bridge varies by varying a supply voltage to the magnetic bridge circuit, which is used to detect water vapor pressure and vary the supply voltage so that the toner density variation due to environmental condition changes depending upon the water vapor pressure is compensated.