Programmable toner concentration and temperature sensor interface method and apparatus

摘要

In accordance with the present invention a toner concentration and temperature sensing apparatus is provided for use with a developer container adapted to retain a quantity of developer material, the developer material including varying concentrations of magnetic carrier material and toner material. The toner sensing apparatus includes a micro controller device for controlling a sensing head to selectively generate a magnetic field within the developer container according to a first set of parameters stored in the micro controller. A preselected portion of the developer material is compressed by the magnetic field and a signal is generated across the sensing device and determining the resistance thereof. The signal across the sensing device varies as a function of the concentration of the toner. The micro controller converts the observed signal into a toner concentration value based on a second set of stored parameters. The developer temperature is obtained by measuring a voltage across a coil comprising the sensing device. The change in coil resistance is a linear function of developer temperature.