A PIEZOELECTRIC SENSOR FOR IN-SITU MONITORING OF XEROGRAPHIC DEVELOPERS

A novel approach to characterizing the mass deposition rate and determ ining the charge-to-mass ratio for a toner within a xerographic develo pment station is presented. This technique consists of suspending a bi ased piezoelectric transducer in the developer and simultaneously meas uring the frequency shift of the transducer and the toning current to the biased electrode. After the measurement step, the sign of the bias on the transducer is reversed, thereby removing the toner and readyin g the device for the next measurement. Results were obtained by using a 1-MHz, AT-cut quartz transducer and measuring its response to variat ions in toner size and charge-to-mass ratio for a two-component develo pment system.