Device for the Simultaneous Measurement of the Available Toner Concentration and Toner Charge of Dry Electrophotographic Developer

Toner concentration and charge/mass of dry electrographic developers are important parameters in the electrophotographic process, relating to both image density and image quality. An apparatus has been developed which allows for the simultaneous determination of these two parameters in a precise and rapid manner. The analysis is essentially a dry gravimetric procedure in which toner concentration is determined by measuring the weight of toner removed by vacuum sieving a known weight of developer. The charge developed as a result of the sieving operation is monitored, and the charge/mass of the toner removed is calculated.