Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!sdd.hp.com!hplabs!hpcc05!hp-ptp!mikef
From: mikef@hp-ptp.HP.COM (Mike_Forman)
Newsgroups: comp.sys.hp
Subject: Re: Ink-jet cartridges
Message-ID: <1320053@hp-ptp.HP.COM>
Date: 31 Oct 90 18:15:39 GMT
References: <194.2729606b@stat.appstate.edu>
Organization: HP Pacific Technology Park - Sunnyvale, Ca.
Lines: 21

This is only an opinion, not a carefully researched answer, but...

The ThinkJet cartridges use air pressure (the ambient air) to help
feed the ink to the print head.  The collapsing rubber bladder 
accomplishes this.  Therefore, to refill the cartridge, you would
need to find a way to take the plastic apart, remove the bladder
without puncturing it, fill it with ink, and reinstall the bladder.
Then, if the plastic isn't too badly destroyed, and if the ink is
compatible with the printer, and if the jets aren't clogged, it
might work.  I can't imagine that there is a cost effective way
to accomplish this.

In addition, there is wear on the electrical contacts with time 
that would cause the cartridge to stop working, anyway.

Having used a ThinkJet for a few years, I can't figure out any
way to refill them.  Best bet is to find a supplies dealer that
will give you a volume discount.  Or, ask HP to donate some  :-)

Once again, the above comments are opinion only, and they do not
reflect the official HP position.