04853718 is referenced by 66 patents and cites 2 patents.

The ink in an ink jet is sensed by a capacitor, one plate of which is coupled to ground through the ink. The absence of ink will appear as a decreased amount of capacitance. In this case the charge of the capacitor will leak off faster, and a sample and hold circuit can sense this to output a signal indicating the absence of ink. The charging signal can either be generated on the chip, which is made from silicon, or can be supplied to the chip. The number of pins on the chip taken for this sensing function can be minimized by multplexing the states of signals supplied to the chip for other purposes to generate the necessary signals to control and operate this sensor.

Title
On chip conductive fluid sensing circuit
Application Number
7/232409
Publication Number
4853718
Application Date
August 15, 1988
Publication Date
August 1, 1989
Inventor
Steven A Buhler
Redondo Beach
CA, US
Abdul M ElHatem
Hawthorne
CA, US
Agent
Robert E Cunha
Assignee
Xerox Corporation
CT, US
IPC
G01D 15/16
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