Appeal No. 1998-2471 Page 2
Application No. 08/222,913
BACKGROUND
The invention at issue in this appeal relates to ink-jet
cartridges for use in computer printers. Specifically, the
invention detects a low supply of ink in such a cartridge.
Several embodiments of the invention are disclosed and
claimed.
Claim 11, which is representative for our purposes,
follows:
11. An ink cartridge for an ink jet printer,
comprising:
a container for supplying ink outwardly of
said container,
wherein said container contains ink having
an electrical resistance and a specific gravity,
an ink exhaustion indicating liquid, not
miscible with said ink located in said container
next to said ink, and having a specific gravity
smaller than the specific gravity of said ink and an
electrical resistance greater than the electrical
resistance of said ink, and
electrodes for detecting the exhaustion of
ink in the container on a basis of a difference in
electrical resistance of said ink and said ink
exhaustion indicating liquid.
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