Toner monitor having magnetic field control

摘要

A toner monitor which measures the magnetic permeability of the developer mix uses a coil around the toner monitor so that when energized with a DC current, the coil acts as an electromagnet to align the developer mix in a consistent fashion at the monitor. The permeability of the mix is measured and the DC current to the coil is inhibited allows the measured sample to fall away or be moved away from the sensor by mixing augers or paddles. When current to the coil is once again restored, another sample is captured and aligned with the monitor. Information concerning the permeability of the developer mix is used to control replenishment of the toner.