초록 ▼

A system is disclosed that monitors the concentration of material in a fluid carrier which includes means for circulating the fluid carrier within a substantially closed loop system and means for measuring the concentration of material carried in the fluid. The measuring means includes means to dete

A system is disclosed that monitors the concentration of material in a fluid carrier which includes means for circulating the fluid carrier within a substantially closed loop system and means for measuring the concentration of material carried in the fluid. The measuring means includes means to detect rapid changes in transmissivity of the fluid carrier, which are indicative of the presence of entrained air bubbles in the fluid carrier, so that measurements of material concentrate under such conditions may be ignored or rejected. Further, to ensure that an accurate measurement of concentrated material depletion is being observed, more than one consecutive measurement is made and validated before concentrate is finally added to the fluid carrier in the system. In the preferred embodiment, the determination of whether air bubbles may be entrained in the fluid carrier is accomplished by determining a disparity between two consecutively measured samples to have been greater than a predetermined value. If such a disparity exists, the measurement sampling rate is increased until the disparity between consecutively measured samples is again less than the predetermined value, at which time sampling is again performed at slower sampling rate. If a disparity exists between several consecutive samples and the disparity in each case remains below the predetermined value, the samples so observed are determined as valid and representative of continuous depletion of the concentrate material in the fluid carrier. When several of these consecutive and validated sample values exceeds a predetermined threshold and there has been no interruption in such sampling due to a disparity between samples greater than the predetermined value, an enablement will be provided to permit concentrate material to be added to the fluid carrier. The system of this invention has particular application to the monitoring the level of toner concentrate in a fluid carrier of fluid toner development system in an electrographic printer/plotter system or machine.

대표청구항 ▼

In a system for monitoring and maintaining a predetermined concentration of a material carried in a fluid medium comprising means for measuring at a first sampling rate the transmissivity of said material carried in said fluid medium, means to determine the amount of any disparity between the measur

In a system for monitoring and maintaining a predetermined concentration of a material carried in a fluid medium comprising means for measuring at a first sampling rate the transmissivity of said material carried in said fluid medium, means to determine the amount of any disparity between the measured transmissivity of a presently measured sample and a previously measured sample, means to increase the first sampling rate to a second sampling rate when said disparity is greater than a predetermined amount, means to count a plurality of consecutively measured samples if said disparity therebetween is less than said predetermined amount and the measured transmissivity of each of said consecutively measured samples are below a predetermined concentration threshold, and means to add said material to said fluid medium when a predetermined number of said consecutively measured samples have been accumulated.