METHOD OF SENSING TONER RESIDUAL

摘要

PURPOSE: A toner residue detecting apparatus is provided to detect the shortage of the toner quickly and accurately so as to maintain optimal printing condition and to control the system by detecting the residue amount of the toner. CONSTITUTION: The toner residue detecting apparatus includes a magnet sensor(110), and a photosensitive sensor(120). The magnet sensor is operated as a result of correlated operation with the toner. The photosensitive sensor is operated relative to the operation of the magnet sensor and generates an on output when the toner and the magnet are departing and off output when the two are approaching. The reference times with respect to an off time during the off interval from the photosensitive sensor is set and stored. The off time output from the photosensitive sensor is compared with the reference times and the residual toner amount is determined with respect to the excess of the off time compared with the reference times.